The human body's response to stress. Stress as a universal adaptation reaction Adaptive reaction to stress

• 1) Provides mobilization of the body's resources: in the stage of anxiety - excessive, in the stage of resistance - adequately to the current stimulus.
• 2) Stress - the reaction provides adaptation to the stimulus.
• 3) Stress can cause illness if the degree of tension in the body exceeds its functional reserves.

Emotional stress. It may be caused by:

• 1) social factors(for example, conflict situations);
• 2) lack of goal achievement;
• 3) the action of very strong factors.

Manifests in the form of a complex of mental and psychosomatic disorders. Often begins with mental agitation. This is manifested by a flash of rage or, conversely, euphoria.

The result of emotional stress is unmotivated actions and depression. Neuroses may occur as a result of emotional stress. Signs of neuroses are neurotic components:

1) mental; 2) psychosomatic; 3) vegetative.

Sustainability Everyone's response to emotional stress is different. It is ensured by the production of opioids and the activation of GABA. As a result, synaptic transmission and the state of neurons are modulated, and the nervous system returns to its original state.

Psychological stress at work.

It arises depending on:

• 1) on the nature of the profession; 2) depending on the personality type; 3) from relationships in the team;
• 4) from the state of the central nervous system in this moment; 5) from previous influences.

Manifests changes in impressionability in the form of daily ups and downs in mood.

Negative emotions are caused by seemingly unimportant factors (for example, starting work at 8 a.m. and therefore having to get up early and travel during rush hours). Psychological stress at work is complemented by disorganization at work, a decrease in productivity and quality of work, and complaints about work stressors appear.

Psychosomatic complaints appear(decreased well-being, various pains, etc.), psychological symptoms of stress appear: feelings of tension, anxiety, depression.

Individual sensitivity and resistance to stress at work depends on the presence of traits in the individual that are a predisposition to stress, on the person’s behavior.

Type A behavior characterized by:

• - desire for competition; - to achieve success; - aggressiveness;
• - haste; - recklessness; - impatience and excitement;
• - explosiveness of speech and tension of the facial muscles;
• - feeling of lack of time and high responsibility. There is increased cholesterol in the blood, accelerated blood clotting, high adrenaline in the blood.

This behavior coincides with the occurrence of coronary insufficiency.

Type B behavior.

Individuals with this behavior are the opposite of Type A.

This is a relaxed type. This behavior is good for health.

Intermediate type of behavior.

Work stressors (time pressure, tension) can transform type B into type A and a less pronounced type A into a more pronounced one.

To understand the role of the stress reaction in the body’s adaptation to the action of stressors and the occurrence of stress damage, let’s consider 5 main, largely interrelated effects of the stress reaction, due to which “urgent” adaptation to environmental factors is formed at the level of systems, organs, cells, and which can translate into damaging effects of stress reactions.

The first adaptive effect of the stress response consists of mobilizing the function of organs and tissues by activating the most ancient signaling mechanism of cell stimulation, namely increasing the concentration in the cytoplasm of the universal function mobilizer - calcium, as well as by activating key regulatory enzymes - protein kinases. During a stress reaction, an increase in the concentration of Ca 2 * in the cell and activation of intracellular processes is carried out due to two factors accompanying the stress reaction.

· Firstly, under the influence of a stress-induced increase in the level of parathyroid hormone (parathyroid hormone) in the blood, Ca 2 * is released from the bones and its content in the blood increases, which helps to increase the entry of this cation into the cells of the organs responsible for adaptation.

· Secondly, the increased “release” of catecholamines and other hormones ensures their increased interaction with the corresponding cell receptors, resulting in activation of the entry mechanism. Ca 2+ into the cell, increasing its intracellular concentration, potentiation of protein kinase activation and, as a consequence, activation of intracellular processes.

Let's look at this in more detail. An excitation impulse arriving at the cell causes depolarization of the cell membrane, which leads to the opening of voltage-dependent Ca 2+ channels, the entry of extracellular Ca 2+ into the cell, the release of Ca 2+ from the store, i.e., from the sarcoplasmic reticulum (SRR) and mitochondria, and increasing the concentration of this cation in the sarcoplasm. By connecting with its intracellular receptor calmodulin (KM), Ca 2+ activates KM-dependent protein kinase, which “triggers” intracellular processes leading to the mobilization of cell function. At the same time, Ca 2+ participates in the activation of the cell’s genetic apparatus. Hormones and mediators, acting on the corresponding receptors in the membrane, potentiate the activation of these processes through secondary messengers formed in the cell with the help of enzymes associated with the receptors. The effect on α-adrenergic receptors activates the enzyme phospholipase C associated with it, with its help the secondary messengers diacylglycerol (DAG) and inositol triphosphate (IF3) are formed from the membrane phospholipid phosphatidylinositol. DAG activates protein kinase C (PK-C), IFz stimulates the release of Ca 2+ from the SPR, which potentiates calcium-induced processes. The effect on β-adrenergic receptors, α-adrenergic receptors and vasopressin receptors (V) leads to the activation of adenylate cyclase and the formation of the second messenger cAMP; the latter activates cAMP-dependent protein kinase (cAMP-PK), which potentiates cellular processes, as well as the functioning of voltage-dependent Ca 2+ channels through which Ca 2+ enters the cell. Glucocorticoids, penetrating into the cell, interact with intracellular steroid hormone receptors and activate the genetic apparatus.

Protein kinases play a dual role.

Firstly, they activate processes responsible for the function of the cell: in secretory cells the release of the corresponding “secret” is stimulated, in muscle cells contraction is enhanced, etc. At the same time, they activate the processes of energy formation in mitochondria, as well as in the glycolytic ATP formation system. In this way, the function of the cell and organs as a whole is mobilized.

Secondly, protein kinases are involved in the activation of the genetic apparatus of the cell, i.e., processes occurring in the nucleus, causing the expression of genes for regulatory and structural proteins, which leads to the formation of the corresponding mRNAs, the synthesis of these proteins and the renewal and growth of cellular structures, responsible for adaptation. With repeated exposure to a stressor, this ensures the formation of a structural basis for sustainable adaptation to this stressor.

However, with an excessively strong and/or prolonged stress response, when the content of Ca 2+ and Na + in the cell increases excessively, the increasing excess of Ca 2+ can lead to cell damage. When applied to the heart, this situation causes a cardiotoxic effect: the so-called “calcium triad” of damage to cellular structures by excess calcium is realized, which consists of irreversible contractural damage to myofibrils, dysfunction of mitochondria overloaded with calcium and activation of myofibrillar proteases and mitochondrial phospholipases. All this can lead to dysfunction of cardiomyocytes and even to their death and the development of focal myocardial necrosis.

The second adaptive effect of the stress response is that “stress” hormones - catecholamines, vasopressin, etc. - directly or indirectly through the corresponding receptors activate lipases, phospholipases and increase the intensity of free radical oxidation of lipids (FRO). This is realized by increasing the calcium content in the cell and activating calmodulin-protein kinases dependent on it, as well as by increasing the activity of the DAG- and cAMP-dependent protein kinases PK-C and cAMP-PK. As a result, the content of free fatty acids, FRO products, and phospholipids in the cell increases. This lipotropic effect of the stress response changes the structural organization, phospholipid and fatty acid composition of the membrane lipid bilayer and thereby changes the lipid environment of membrane-bound functional proteins, i.e. enzymes, receptors. As a result of the migration of phospholipids and the formation of lysophospholipids, which have detergent properties, the viscosity decreases and the “fluidity” of the membrane increases.

During a stress reaction or the administration of catechol mines, activation of SRO in the heart, liver, skeletal muscles and other organs has been proven.

The adaptive significance of the lipotropic effect of the stress response is obviously great, since this effect can quickly optimize the activity of all membrane-bound proteins, and therefore the function of cells and the organ as a whole, and thus contribute to the urgent adaptation of the body to the action of environmental factors. However, with an excessively long and intense stress reaction, an increase in precisely this effect, i.e. excessive activation of phospholipases, lipases and SPO can lead to membrane damage and acquires a key role in converting the adaptive effect of the stress response into a damaging one.

Free fatty acids that accumulate as a result of excessive hydrolysis of triglycerides by lipases and the hydrolysis of phospholipids by phospholipases, as well as lysophospholipids formed as a result of the hydrolysis of phospholipids, become damaging factors. As a result, the structure of the membrane bilayer changes. At high concentrations, such compounds form micelles, which “break” the membrane and disrupt its integrity. As a result, the permeability of cell membranes for ions and especially for Ca 2+ increases.

SRO activation products also become damaging factors in the lipotropic effect during an intense or prolonged stress reaction. As SRO progresses, all large quantity unsaturated phospholipids are oxidized and in membranes the proportion of saturated phospholipids in the microenvironment of functional proteins increases. This leads to a decrease in membrane fluidity and the mobility of the peptide chains of these proteins. The phenomenon of “freezing” of these proteins into a more “hard” lipid matrix occurs and, as a result, the activity of the proteins decreases or is completely blocked.

Thus, excessive enhancement of the lipotropic effect of the stress response, i.e. its “lipid triad” (activation of lipases and phospholipases, activation of FRO and increase in the amount of free fatty acids), can lead to “damage to biomembranes, which plays a key role in the inactivation of ion channels, receptors and ion pumps. As a result, the adaptive lipotropic effect of the stress response may turn into a damaging effect.

The third adaptive effect of the stress response is in the mobilization of the body’s energy and structural resources, which is expressed in an increase in the concentration of glucose, fatty acids, nucleides, and amino acids in the blood; as well as in the mobilization of the function of the blood circulation of breathing. This effect leads to an increase in the availability of oxidation substrates, initial products of biosynthesis and oxygen for organs whose work is increased. In this case, glucagon is released during stress somewhat later than catecholamines and, as it were, duplicates and reinforces the effect of catecholamines. This is of particular importance in conditions where the effect of catecholamines is not fully realized due to desensitization of beta-adrenergic receptors caused by an excess of catecholamines. In this case, activation of adenylate cyclase occurs through glucagon receptors (Tkachuk, 1987t.). Another source of glucose is the activation of protein hydrolysis and an increase in the pool of free amino acids, which occurs under the influence of glucocorticoids and, to a certain extent, parathyroid hormone, as well as the activation of gluconeogenesis in the liver and skeletal muscles. At the same time, glucocortioids, acting on their receptors at the level of the cell nucleus, stimulate the synthesis of the key enzymes of gluconeogenesis, glucose-6-phosphatase, phosphoethanolpyruvate carboxykinase, etc. (G6likbvG 1988). The result of activation of gluconeogenesis is the transamination of amino acids and the formation of of glucose. It is important that both hormonal mechanisms of glucose mobilization during a stress response ensure the timely supply of glucose to such vital organs as the brain and heart. In the stress response associated with acute physical activity, the stress response that occurs under the influence of glucocorticoids in the skeletal muscles, activation of the glucose-adenine cycle, which ensures the formation of glucose from amino acids directly in muscle tissue.

In the mobilization of fat depots under stress main role play catecholamines and glucagon, which indirectly through the adenylate cyclase system activate lipases and lipoprotein lipases in adipose tissue, skeletal muscles, and the heart. Parathyroid hormone and vasopressin appear to play a role in the hydrolysis of blood triglycerides, the secretion of which increases during stress, as mentioned above. The pool of fatty acids thus created is used in the heart and skeletal muscles. In general, the mobilization of energy and structural resources is expressed quite strongly during a stress reaction and ensures “urgent” adaptation of the body to a stressful situation, i.e. is an adaptive factor. However, in conditions of a prolonged intense stress reaction, when the formation of “structural traces of adaptation” does not occur, in other words, there is no increase in the power of the energy supply system, intensive mobilization of resources ceases to be an adaptive factor and leads to progressive exhaustion of the body.

The fourth adaptive effect of the stress response can be designated as “directed transfer of energy and structural resources to the functional system that carries out a given adaptive reaction.” One of the important factors of this selective redistribution of resources is the well-known, local in its form, “working hyperemia” in the organs of the system responsible for adaptation, which is simultaneously accompanied by vasoconstriction of the “inactive” organs. Indeed, during a stress response caused by acute physical activity, the proportion of minute volume of blood flowing through skeletal muscles increases by 4-5 times, and in the digestive organs and kidneys, on the contrary, this figure decreases by 5-7 times compared to the resting state . It is known that stress causes an increase in coronary blood flow, which provides increased cardiac function. The main role in the implementation of this stress response effect belongs to catecholamines, vasolressin and angiotensin, as well as substance P. The key local factor of “working hyperemia” is nitric oxide (NO) produced by the vascular endothelium. "Working hyperemia" provides an increased flow of oxygen and substrates to a working organ through vasodilation in this organ

It is obvious that the redistribution of the body's resources under stress, aimed at primarily providing organs and tissues responsible for adaptation, regardless of its mechanism, is an important adaptive phenomenon. However, if the stress reaction is overly expressed, it can be accompanied by ischemic dysfunction and even damage to other organs that are not directly involved in this adaptive reaction. For example, ischemic ulcers of the gastrointestinal tract that occur in athletes under heavy, prolonged emotional and physical stress.

The fifth adaptive effect of the stress response is that with a single sufficiently strong stressor, following the well-known “catabolic phase” of the stress reaction discussed above (the third adaptive effect), a significantly longer “anabolic phase” is realized. It manifests itself as a generalized activation of the synthesis of nucleic acids and proteins in various organs. This activation ensures the restoration of structures damaged during the catabolic phase and is the basis for the formation of structural “traces” and the development of sustainable adaptation to various environmental factors. This adaptive effect is based on hormonal activation of the formation of secondary messengers IFZ and DAG, an increase in calcium levels in the cell, as well as the effect of glucocorticoids on the cell. In addition to mobilizing the function of the cell and its energy supply, this process has “exit” to the genetic apparatus of the cell, which leads to the activation of protein synthesis. In addition, it has been shown that during the unfolding of the stress reaction, the secretion of somatotropic hormone (growth hormone), insulin, and thyroxine, which are “inhibited” at the beginning of the reaction, is activated, which potentiate protein synthesis and can play a role in the development of the anabolic phase of the stress reaction and activation of cell growth structures that bore the greatest load during stress mobilization of cell function. However, it should be borne in mind that excessive activation of this adaptive effect appears to; may lead to unregulated cell growth.

In general, we can conclude that with a prolonged intense stress reaction, all the considered main adaptive effects are transformed into damaging ones and this is how they can become the basis of stress-related diseases.

The effectiveness of the adaptive response to stress and the likelihood of stress-induced damage and illness are largely determined, in addition to the intensity and duration of the stressor, by the state of the stress system: its basal (initial) activity and reactivity, i.e., the degree of activation under stress, which are genetically determined , but can change in the course of individual life.

Chronically increased basal activity of the stress system and/or its excessive activation during stress is accompanied by increased blood pressure, dysfunction of the digestive organs, and suppressed immunity. In this case, cardiovascular and other diseases may develop. Reduced basal activity of the stress system and/or its inadequate activation during stress are also unfavorable. They lead to a decrease in the body’s ability to adapt to the environment, solve life problems, and to the development of depressive and other pathological conditions.

In addition to physiological ones, psychological adaptive reactions are possible that help a person resist the stressor. A person reacts to a stressor with anxiety, tension and frustration. Adaptive forms of behavior are also a mechanism for adapting to stress, and they are focused either on performing a task (attack behavior, stress avoidance, compromising behavior) or on self-defense. In table Figure 9-1 presents options for behavioral responses to stress.

Anxiety- a psychological reaction expressed in a feeling of horror (fear) or anxiety that arose for unclear reasons. Various levels anxiety and the corresponding types of behavior are presented in table. 9-2.

Table 9-1. Options for behavioral responses to stress

Table 9-2. Anxiety levels

Understanding, which increases with mild anxiety, practically disappears at the level of panic, in which perception environment becomes distorted. A person's condition can fluctuate between several levels of anxiety. The level of anxiety that arises and its manifestation depend on the person’s age, understanding of the need for treatment, level of self-esteem and maturity of the mechanisms for dealing with stressors. People with high anxiety may transmit feelings of anxiety to others. For example, a very anxious patient may increase the anxiety of a family member, and vice versa. The manifestation of anxiety may be the result of a release of energy necessary to restore mental balance. These reactions can be expressed as adaptive or maladaptive behavior. The types of behavioral reactions that occur are influenced by mental, social and cultural factors, general personality development, past experiences, values ​​and economic status. Anxiety is very common among patients and their loved ones.

Aggressiveness- a reaction that gives a person the opportunity to feel less helpless and stronger, to relieve anxiety. Manifestations of aggression are possible when a person’s “I-concept” is threatened. People often get angry because of loss of health, lack of understanding of what is happening to them, and therefore become irritable and overly demanding.

Depression- a common reaction to information about a serious illness. Feelings of sadness or grief may manifest themselves in the following ways:

The desire to communicate with other people disappears;

Interest in active activities and surroundings disappears;

There is concern about the disease and the amount of necessary assistance (care);

Expresses a desire to die or anxious thoughts about death;

Behavior becomes predominantly dependent;

There are complaints of fatigue or insomnia;

Tearfulness occurs.

Any talk of suicide should be taken seriously and should be reported to your doctor immediately.

Secretive behavior (secrecy) often appears during illness. It helps the patient conserve mental and physical energy to cope with stressors and speed up recovery and recovery. Secretive patients usually do not cause problems and are often called good patients. They are undemanding and often have low self-esteem, so they can be “missed.”

Suspicion may appear due to a feeling of helplessness, lack of control over circumstances. Suspicious patients are distrustful (for some this may be a personality trait). They are often wary of personnel, routine manipulations and procedures. Conversations in a whisper within earshot of such a patient may raise suspicions that others are hiding something important.

Somatic behavior- a habitual reaction to stress, which can otherwise be called flight into illness. People express anxiety by complaining about a variety of symptoms (pain, shortness of breath, constipation, diarrhea, etc.). Vague complaints of low back pain, headache or fatigue are used by the patient to attract attention. Health care providers often become angry with patients with somatic behavior due to frequent and vague complaints. Nursing staff may make the mistake of not responding to complaints from such patients because they may well be unfeigned.

9.3. NURSING CARE IN ADAPTATION TO STRESS

Nursing staff working in medical institutions constantly face stress. The environment is often stressful for the patient as well. For example, a patient’s limb was amputated as a result of injury or surgery, or his face was disfigured due to a burn. To cope with such experiences, patients need professional help: you can let the patient express their concerns, help him formulate immediate and long-term goals for care. In this way, the nurse helps the patient participate in the organization of treatment and care.

Some people solve problems without thinking for a long time, others, on the contrary, do it very thoughtfully. Problem solving is a way of overcoming a stress response that will be more effective if you adhere to the following steps:

Definition of the problem (impact of the stressor);

Establishment of factors influencing the problem (stressor);

Exploring alternative goals and the consequences of achieving them;

Assessing the effectiveness of nursing care.

Some behavioral reactions that indicate the presence of stress in a person:

Continuous walking back and forth;

Decreased activity, even among people who are fond of entertainment (passivity, prolonged stay in one position, etc.);

Changes in daily activities (decreased appetite, constipation, diarrhea);

Changing the perception of reality and social relationships;

Changing attitude towards work.

In a medical facility, stressors can be isolation and the inability to communicate with loved ones on a daily basis, a large flow of information, excessive noise, changes in the usual way of life, etc. Sometimes the nurse’s manipulations, performed without explanation of reasons or goals, become a stressor. Therefore, the nurse, in an attempt to relieve the patient's anxiety, helps him cope with stress. When assessing the patient’s condition, one must be able to identify physiological, psychological, and sometimes spiritual indicators of stress.

Physiological indicators of stress include:

Increase or decrease in blood pressure;

Increased heart rate and breathing;

Sweaty palms or cold hands and feet;

drooping posture, fatigue;

Changes in appetite, nausea, vomiting, diarrhea, bloating;

Change in body weight;

Change in frequency of urination;

Pathological changes in the results of laboratory, instrumental and instrumental studies;

Psychological indicators of stress include:

Abuse of psychotropic drugs;

Changing habits related to eating, sleeping, and favorite activities;

Mental exhaustion, irritability;

Lack of motivation, emotional outbursts and frequent tearfulness;

Decreased performance and quality of work, forgetfulness, deterioration of attention to detail, absent-mindedness (“daydreaming”, “with your head in the clouds”), absenteeism;

Increased incidence of illness, apathy, susceptibility to accidents.

Signs of stress within the “I-concept”:

Refusal to meet with friends and acquaintances;

Reluctance to look in the mirror, touch or look at the affected part of the body;

Negative perception of references to impairment of function, deformity, or deformity;

Reluctance to use prostheses in the absence of a limb;

Refusal of efforts aimed at rehabilitation.

When conducting an initial assessment of the patient's condition, the nurse should identify signs of a violation of the self-concept by asking the patient the following questions:

How has illness (violence, divorce, etc.) affected your life?

How do you adapt to the changes that have come to your life?

How can you and your loved ones cope with the changes that have occurred?

Nursing analysis of anxiety is best categorized by levels of anxiety. Possible reasons worries:

Changes in socioeconomic status, role functioning, environment, or types of habitual interactions.

Goals of care depend on the behaviors exhibited by the anxious patient and should be accompanied by a reduction in inappropriate behavior. For example:

The patient will feel more relaxed and less anxious;

The patient will note that sleep has improved;

Pathological symptoms (increased heart rate, increased blood pressure, etc.) will disappear;

Regular bowel movements will improve;

The patient's muscles will be relaxed;

The nurse (together with the patient) draws up the optimal plan of care. When implementing it, social support from relatives and friends is important. Nursing care is aimed at achieving the following goals:

Reducing the frequency of stressful situations;

Elimination of physiological, psychological and spiritual reactions to stress (symptoms of stress);

Optimizing behavioral, emotional and spiritual responses to stress.

When planning nursing care in case of deformation of the “I-concept”, the patient, with the help of a nurse, must change the current situation: start sharing his thoughts and feelings towards himself, change his attitude

to one's own "I". It should be borne in mind that the goal may be long-term, sometimes many years. Much of the success of a nursing intervention will depend on the nurse's ability to establish trusting relationship with the patient and his relatives.

The nurse determines and formulates the goals of nursing care:

The patient will agree to discuss the changes that have occurred;

The patient will be able to discover positive qualities in himself, etc.

When a patient's self-esteem decreases, the nurse must earn his trust. Her art of communication, together with the efforts of relatives, a psychologist, and a rehabilitation specialist, will allow the patient to talk about himself, interact adequately with other people, force him to agree to treatment, rehabilitation procedures, or refuse bad habits that destroy the body (smoking, alcohol), etc.

When role behavior is disrupted, the nurse strives to ensure that the patient can discuss ways to cope. new role; influences his behavior, returning him to his previous role.

Nursing interventions designed to combat long-term stress aim to achieve the following goals:

Changing the patient's lifestyle;

Providing the patient with a strict daily routine, balanced nutrition, adequate physical activity;

Limitation or complete refusal of the patient from bad habits (alcohol, smoking);

Maintaining or developing self-esteem, suppressing unpleasant thoughts;

Training in methods of psychophysical self-regulation (overcoming pain, fatigue and loss of strength, fear, depression, timidity, shyness), consisting of special exercises to concentrate the psyche on a state of rest. This skill helps break the pattern of modern lifestyle - stressful situations - mental overload - illness;

Training family members, friends and colleagues in social support techniques (ability to listen, understand, advise).

Approach to use when working with a patient exhibiting denial:

Explore the causes of fear and anxiety underlying denial;

Avoid direct confrontation;

Assist the individual in carrying out planned nursing interventions;

Reassure the patient of his worth as a person, despite his dependent condition;

Encourage behavior that indicates acceptance of reality;

It is correct, but firmly, to outline the acceptable limits of denial, the violation of which interferes with treatment.

Approach to use when working with a patient exhibiting regression:

Investigate observed behavior;

Discuss the patient's goals;

Make appropriate changes to your care plan.

Approach to use when dealing with an aggressive patient:

Provide opportunities for the patient to express their feelings and discuss their reasons;

Leave the patient's hostility unanswered and do not make the person feel guilty;

Anticipate patient problems;

Maintain eye contact when communicating with the patient;

Approach the patient calmly, openly, without being aggressive;

Reduce the intensity of irritants in the environment;

Set limits (framework) of aggressiveness;

Use medications or physical restraints only if all other measures are ineffective and the patient is dangerous.

Approach to take when caring for a patient with depressive behavior:

Treat the patient seriously;

Let the patient know that you understand his feelings;

Help the patient express his feelings;

Recognize the patient's right to experience negative emotions;

Listen to the patient to release negative emotions.

Approach used when working with a secretive patient:

Spending time with this patient, at least silently, to increase his self-esteem;

Gently encourage the patient to talk, express their feelings, and connect with others.

Approach to use when dealing with a suspicious patient:

Allow the patient to talk about their concerns, but do not insist on it;

Keep promises made to the patient in order to gain his trust;

Avoid excessive zeal, which may aggravate suspicion;

Explain the course of procedures and routine manipulations;

Avoid whispering or discussing the patient in his presence

Approach used when working with a patient with somatic behavior:

Believe all symptoms and report them to your doctor;

Spend time with this patient;

Listen to the patient's health complaints.

Nursing interventions in relation to a person experiencing stress can be general, designed to reduce the impact of the stressor, and crisis, carried out in case of panic to manage stress. General interventions are aimed at maintaining the body's adaptive mechanisms, combating stressors and providing an optimal environment that allows a person to mobilize his strength.

/ Ekzamen_psikhiatria_1 / 79. Reactions to severe stress and adaptation disorders

Reactions to severe stress are currently (according to ICD-10) divided into the following:

Post-traumatic stress disorders;

Acute reaction to stress

A transient disorder of significant severity that develops in individuals without apparent mental disorder in response to exceptional physical and psychological stress and that usually resolves within hours or days. Stress may be a severe traumatic experience, including a threat to the safety or physical integrity of the individual or loved one (eg, natural disaster, accident, battle, criminal behavior, rape) or an unusually abrupt and threatening change in the social status and/or environment of the sufferer, e.g. the loss of many loved ones or a fire in the house. The risk of developing the disorder increases with physical exhaustion or the presence of organic factors (for example, in elderly patients).

Individual vulnerability and adaptive capacity play a role in the occurrence and severity of acute stress reactions; This is evidenced by the fact that not all people exposed to severe stress develop this disorder.

Symptoms show a typical mixed and fluctuating pattern and include an initial state of “dazedness” with some narrowing of the field of consciousness and decreased attention, inability to respond adequately to external stimuli, and disorientation. This state may be accompanied by either further withdrawal from the surrounding situation up to the point of dissociative stupor, or by agitation and hyperactivity (flight or fugue reaction).

Autonomic signs of panic anxiety (tachycardia, sweating, flushing) are often present. Symptoms usually develop within minutes of exposure to a stressful stimulus or event and disappear within two to three days (often hours). Partial or complete dissociative amnesia may be present.

Acute reactions to stress occur in patients immediately after traumatic exposure. They are short-lived, from several hours to 2-3 days. Autonomic disorders, as a rule, are of a mixed nature: there is an increase in heart rate and blood pressure and, along with this, pale skin and profuse sweat. Motor disturbances are manifested either by sudden agitation (throwing) or retardation. Among them, the affective-shock reactions described at the beginning of the 20th century are observed: hyperkinetic and hypokinetic. With the hyperkinetic variant, patients rush around non-stop and make chaotic, unfocused movements. They do not respond to questions, much less the persuasion of others, and their orientation in their surroundings is clearly disturbed. With the hypokinetic variant, patients are sharply inhibited, they do not react to their surroundings, do not answer questions, and are stunned. It is believed that in the origin of acute reactions to stress, not only a powerful negative impact plays a role, but also the personal characteristics of the victims - old age or adolescence, weakness of any somatic disease, such character traits as increased sensitivity and vulnerability.

In ICD-10 the concept post-traumatic stress disorder combines disorders that do not develop immediately after exposure to a psychotraumatic factor (delayed) and last for weeks, and in some cases for several months. These include: the periodic appearance of acute fear (panic attacks), severe sleep disturbances, obsessive memories of a traumatic event that the victim cannot get rid of, persistent avoidance of places and people associated with the traumatic factor. This also includes long-term persistence of a gloomy and melancholy mood (but not to the level of depression) or apathy and emotional insensitivity. Often people in this state avoid communication (run wild).

Post-traumatic stress disorder is a non-psychotic delayed response to traumatic stress that can cause mental health problems in almost anyone.

Historical research in the field of PTSD has developed independently of stress research. Despite some attempts to build theoretical bridges between “stress” and post-traumatic stress, the two areas still have little in common.

Some of the famous stress researchers, such as Lazarus, who are followers of G. Selye, largely ignore PTSD, like other disorders, as possible consequences stress, limiting the field of attention to studies of the characteristics of emotional stress.

Stress research is experimental in nature, using special experimental designs under controlled conditions. Research on PTSD, in contrast, is naturalistic, retrospective, and largely observational.

Criteria for post-traumatic stress disorder (according to ICD-10):

1. The patient must be exposed to a stressful event or situation (both short-term and long-term) of an exceptionally threatening or catastrophic nature, which can cause distress.

2. Persistent memories or “reliving” of the stressor in intrusive flashbacks, vivid memories and recurring dreams, or re-experiencing grief when exposed to situations reminiscent of or associated with the stressor.

3. The patient must demonstrate actual avoidance or a desire to avoid circumstances reminiscent of or associated with the stressor.

4. Either of the two:

4.1. Psychogenic amnesia, either partial or complete, regarding important periods of exposure to a stressor.

4.2. Persistent symptoms of increased psychological sensitivity or excitability (not observed before the stressor), represented by any two of the following:

4.2.1. difficulty falling or staying asleep;

4.2.2. irritability or angry outbursts;

4.2.3. difficulty concentrating;

4.2.4. increased level of wakefulness;

4.2.5. enhanced quadrigeminal reflex.

Criteria 2,3,4 occur within 6 months after a stressful situation or at the end of a period of stress.

Clinical symptoms of PTSD (according to B. Kolodzin)

1. Unmotivated vigilance.

2. “Explosive” reaction.

3. Dullness of emotions.

5. Impaired memory and concentration.

7. General anxiety.

8. Attacks of rage.

9. Abuse of narcotic and medicinal substances.

10. Unbidden memories.

11. Hallucinatory experiences.

13. Thoughts about suicide.

14. “Survivor Guilt.”

Speaking, in particular, about adaptation disorders, one cannot help but dwell in more detail on such concepts as depression and anxiety. After all, they are the ones that always accompany stress.

Previously dissociative disorders were described as hysterical psychoses. It is understood that in this case the experience of a traumatic situation is displaced from consciousness, but is transformed into other symptoms. The appearance of very pronounced psychotic symptoms and loss of sound in the experiences of the experience psychological impact negative and mark dissociation. This same group of experiences includes conditions previously described as hysterical paralysis, hysterical blindness, and deafness.

The secondary benefit for patients of the manifestations of dissociative disorders is emphasized, that is, they also arise through the mechanism of escape into illness, when psychotraumatic circumstances are unbearable and super-strong for the fragile nervous system. A common feature of dissociative disorders is their tendency to recur.

The following forms of dissociative disorders are distinguished:

1. Dissociative amnesia. The patient forgets about the traumatic situation, avoids places and people associated with it; reminders of the traumatic situation meet with fierce resistance.

2. Dissociative stupor, often accompanied by loss of pain sensitivity.

3. Puerilism. Patients respond to psychotrauma with childish behavior.

4. Pseudo-dementia. This disorder occurs against the background of mild stunning. Patients are confused, look around in bewilderment and display the behavior of the weak-minded and incomprehensible.

5. Ganser syndrome. This condition resembles the previous one, but includes passing speech, that is, patients do not answer the question (“What is your name?” - “Far from here”). It is impossible not to mention neurotic disorders associated with stress. They are always acquired, and not constantly observed from childhood to old age. In the origin of neuroses, purely psychological causes (overwork, emotional stress) are important, and not organic influences on the brain. Consciousness and self-awareness are not impaired in neuroses; the patient is aware that he is sick. Finally, with adequate treatment, neuroses are always reversible.

Adjustment disorder observed during the period of adaptation to a significant change social status(loss of loved ones or long-term separation from them, refugee status) or to a stressful life event (including a serious physical illness). In this case, a temporary connection between stress and the resulting disorder must be proven - no more than 3 months from the onset of the stressor.

At adjustment disorders in the clinical picture the following are observed:

feeling of inability to cope with the situation or adapt to it

some decrease in productivity in daily activities

tendency towards dramatic behavior

Based on their predominant characteristics, the following are distinguished: adjustment disorders:

short-term depressive reaction (no more than 1 month)

prolonged depressive reaction (no more than 2 years)

mixed anxious and depressive reaction, with a predominance of disturbance of other emotions

reaction with a predominance of behavioral disturbances.

Among other reactions to severe stress, nosogenic reactions are also noted (develop in connection with a severe somatic illness). There are also acute reactions to stress, which develop as reactions to an exceptionally strong, but short-lived (over hours, days) traumatic event that threatens the mental or physical integrity of the individual.

Affect is usually understood as a short-term strong emotional disturbance, which is accompanied not only by an emotional reaction, but also by the excitement of all mental activity.

Highlight physiological affect, for example, anger or joy, not accompanied by confusion, automatisms and amnesia. Asthenic affect- quickly depleted affect, accompanied by depressed mood, decreased mental activity, well-being and vitality.

Thenic affect characterized by increased well-being, mental activity, and a sense of personal strength.

Pathological affect- a short-term mental disorder that occurs in response to intense, sudden mental trauma and is expressed in the concentration of consciousness on traumatic experiences, followed by an affective discharge, followed by general relaxation, indifference and often deep sleep; characterized by partial or complete amnesia.

In some cases, pathological affect is preceded by a long-term psychotraumatic situation and the pathological affect itself arises as a reaction to some kind of “last straw”.

3. Standard nonspecific adaptive reactions: training, activation, stress. Their phases, mechanisms.

Nonspecific– occur in response to any stimulus.

Adaptive – provide adaptation to the action of stimuli. Therefore, the nature of the reaction, its severity and duration depend on the nature of the stimulus.

Types of adaptive reactions.

The nature of the response to the stimulus is determined.

1) Tensions sympathoadrenal and hypothalamic-pituitary systems, mobilizing the body's resources for adaptation.

2) Resistance, i.e., the stability of behavior, the control apparatus that maintains homeostasis, to the action of factors.

3) Reactivity– the ability to respond to a stimulus. Depends on the functional state of the reacting structures.

Characteristics of the training response.

1) Orientation stage– occurs 6 hours after exposure, lasts 24 hours.

Accompanied by a moderate increase in the secretion of glucocorticoids, excitation occurs in the central nervous system, followed by inhibition. The excitability of the hypothalamus decreases. The body stops responding to weak stimuli. For the next stage to occur, a higher stimulus strength is needed.

2) Stage of restructuring.

a) There is a decrease in the secretion of glucocorticoids and an increase in mineralocorticoids.

b) The body's defenses increase.

c) In the central nervous system the threshold of irritation increases, metabolism is reduced, there is a minimal consumption of plastic materials, they accumulate. This stage lasts a month or more.

d) Stage of training.

Occurs when the strength of the stimulus reaches new levels of the arousal threshold.

Resistance to irritants increases due to increased activity of protective forces. In the brain there are processes of anabolism, in the central nervous system there is protective inhibition.

The cessation of the action of weak stimuli leads to detraining.

Characteristics of the activation reaction.

Occurs when exposed to irritants of moderate strength. Has 2 stages:

1) Primary activation stage. In the central nervous system there is moderate arousal, moderate motor activity. Increased secretion of somatotropic, thyroid-stimulating and gonadotropic hormones. The processes of anabolism are increased. There is an increase in albumin in the brain, liver, spleen, testes, and blood serum.

Defenses are activated and resistance is increased.

2) Stage of persistent activation occurs with repeated exposure to medium-strength stimuli. Characterized by activation of neurons of the reticular formation. In the central nervous system, excitation predominates, a persistent increase in protective forces is noted, resistance is increased and persists for some time after the cessation of the action of the stimuli.

A stereotypical psychophysiological reaction to significant and strong influences, leading to the mobilization of the body's defenses.

Stress reaction develops due to:

1) the action of factors.

The stimulus becomes stressful:

A) due to interpretation or

b) if it has a sympathomimetic effect;

2) individual properties VND and CNS;

3) the amount of functional reserve physiological systems.

Characteristics of stress phases.

Changes in response to a stressor mental condition, emotional status, motor acts, autonomic reactions. Such changes are launched:

1) nervously through direct innervation of organs that respond to stimuli;

2) neuroendocrine by the sympathoadrenal system.

3) endocrine pathway - the main role in the anxiety phase is played by hormones of the adrenal cortex.

Phases of increased resistance.

The task of this phase is to maintain a new (increased) operating mode of physiological systems and the body.

Variants of the outcome of stress.

1) Eustress – good stress.

At the same time, the level of tension in the body does not exceed the boundaries of the functional reserve of the systems. As a result, adaptation to the current factor and the elimination of stress develops.

2) Distress – bad stress.

The tension required to adapt to the stimulus goes beyond the body's capabilities, and exhaustion occurs. It manifests itself in symptoms of stress or even illness.

Regulation and self-regulation of functions (systems of regulation of functions, levels and contours of regulation, their relationships, the concept of health and illness from the position of regulation and self-regulation).

Regulation and self-regulation of functions:

I) Operation of regulatory systems.

There are two methods and two systems for regulating functions:

1) Nervous regulation > unconditioned reflex (provides automated

management of the activities of bodies and

conditioned reflex - purposeful activity.

2) Humoral > carried out by primary and secondary messengers.

II) Levels and contours of regulation, their relationships.

There are several levels of regulation in the body:

a) local (tissue) – microregional;

The functioning of the levels of regulation is carried out through self-regulation circuits.

Contours of local level of regulation.

1) Myogenic circuit– includes a shift in tissue geometry and the occurrence of a response. For example: stretching of the smooth muscles of blood vessels - reducing their lumen; stretching of cardiac myocytes – increasing the force of their contraction.

Humoral circuit local level of regulation includes a change in the amount or appearance of new humoral substances in the intercellular spaces. This automatically leads to a change in tissue activity.

Local level of regulation and activity of other levels.

The severity of the functioning of the myogenic and humoral circuits at the local level ensures:

1) activation of receptors of the region (regions) and transmission of the afferent signal to the central nervous system;

2) stimulation of the central nervous system through the humoral route through the internal environment of the body. As a result, higher-level regulatory systems are activated.

Abbreviation > H+ > Blood > Central and peripheral chemoreceptors

Transport-metabolic

Concept of health and illness(from the standpoint of regulation and self-regulation).

According to I.P. Pavlov, the principle of self-regulation is the law of maintaining the stability of functions, and hence health. Disease is a violation of homeostasis. It is important for the doctor to establish the cause of the disorder, which may lie in a defect in the operation of various parts of the system for maintaining homeostasis: a signaling device, a control apparatus, a corrective device, and the structural and functional state of the tissue. Impaired health may be associated with impaired regulation and self-regulation of somatic, autonomic functions, their integration, purposeful activity and its provision.

Functions of the cerebellum. Symptoms of cerebellar damage in humans

The cerebellum takes part in the system of control and coordination of movements at three levels.

1. Vestibulocerebellum provides the movements necessary to maintain balance.

2 Spinocerebellum provides coordination mainly of the distal parts of the extremities (especially the hands and fingers).

3. Neocerebellum receives all connections from the motor cortex and adjacent areas of the premotor and somatosensory areas of the brain. It transmits signals back to the cerebrum, planning a sequence of actions together with the sensorimotor area and anticipating future actions tens of seconds in advance.

— In persons with vestibulocerebellar disorders, balance is more impaired when attempting rapid movements than during rest. This is especially true when trying to change the direction of body movement. This indicates that vestibulocerebtllum controls the balance between agonistic and antagonistic contractions of the muscles of the spine, hip and shoulder girdle during rapid changes in body positions.

— The intermediate zone of each of the cerebellar hemispheres receives two types of information. At the moment the movement begins, information comes from the motor cortex and the red nucleus, informing the cerebellum about sequences of the proposed movement plan. At the same time, information from the peripheral parts of the body (especially from the proprioceptors of the limbs) comes to the cerebellum, telling the cerebellum about the nature of real movement.

— Spinocerebellum ensures smooth, coordinated movements of agonists and antagonists, comparing movements planned by the cortex with movements actually performed. This is accomplished through the anterior spinocerebellar tract, which transmits “copies” of real motor signals to the cerebellum.

Almost all movements of our body are “pendulum-like”. For example, when moving a hand, there is execution inertia and there may be excess inertia before the movement is stopped. Due to inertia, all pendulum-like movements tend to exceed. If a person with a damaged cerebellum has a range of movements that exceeds the norm, then with the help of consciousness he recognizes this and tries to make a movement in the opposite direction. But the limb (due to inertia and disruption of the cerebellar correction mechanism) continues to oscillate back and forth until the arm returns to its original position. This phenomenon is action tremor, or intentional tremor. If the cerebellum is not damaged and is trained accordingly, then subconscious signals will accurately stop the movement at a given point and stop the tremor. This damping function will be performed by spinoceredellum.

The function of the spinocerebelum includes the control of very fast short movements called ballistic (for example, typing on a computer keyboard or saccadic movements of the eyeball). After removal of the cerebellum, movements begin and end slowly, and they are weaker, that is, the usual automaticity of ballistic movements is lost.

Planning a sequence of movements is carried out by the lateral zones of the cerebellar hemispheres together with the pemotor and sensory areas of the cerebral cortex with constant bilateral communication of the cerebral cortex with the basal ganglia. The “plan” for sequential movements arises in the sensory and premotor areas of the cortex, from where this plan is transmitted to the lateral parts of the cerebellar hemispheres. Then, through many bidirectional connections between the cerebellum and the cerebral cortex, the necessary motor signals provide the transition from one movement to the next. Importantly, the neurons of the deep dentate nuclei of the cerebellum develop patterns of impulse activity for subsequent movements at this moment, when the actual movements are just beginning. Important function neocerbellum is the timing of each subsequent movement. Removal of the lateral sections of the cerebellar hemispheres leads to the loss of the subconscious ability to calculate the time of occurrence of certain body movements.

Neocerebellum plays a role in predicting the time sequence not only for movements, but also for other body systems. In particular, a person, based on visual observations, can predict how quickly a particular moving object can approach some object.

The cerebellum and motor learning.

The degree of participation of the cerebellum in motor coordination and learning is revealed when attempting to perform new motor acts. As a rule, new movements are initially uncertain, imprecise, and require a lot of effort. After repeated repetitions, the movements become more precise and easily reproducible. The basis for such learning is the input through the olive nuclei. Each Purkinje cell receives from 250 thousand to 1 million mossy fibers as input and only one climbing fiber from the inferior olive, but this climbing fiber forms 2 - 3 thousand synapses on the Purkinje cell. Activation of the climbing fiber causes a large complex discharge (spike) in the Purkinje cell; this spike causes a long-term, persistent change in the spectrum of mossy fiber input activity in the same Purkinje cell. The activity of climbing fibers increases when new movements are learned. Selective damage to the olivary complex impairs the ability to regulate motor acts.

Features of digestion in the large intestine. The act of defecation.

Motor function of the large intestine.

200–500 ml of chyme enters the large intestine through the ileocecal valve. per day. The sphincter opens after 1 – 4 minutes and 15 ml. chyme enters the cecum, it stretches and the sphincter closes. This is a viscero-visceral reflex.

Colon movements:

2) peristaltic(weak, strong and very strong or propulsive). They begin in the cecum and move the contents to the sigmoid or rectum.

3) antiperistaltic contractions provide compaction feces.

1) Local– when mechanoreceptors are irritated by intestinal contents.

2) Extraintestinal influences– carried out from various receptors of the esophagus, stomach, oral cavity, conditioned reflex.

Motor skills are inhibited through the sympathetic system.

Parasympathetic – activates. The ANS acts on the MCC or directly on intestinal smooth muscle.

Defecation. Defecation reflexes.

1. Own recto-sphincteric reflex occurs when the wall of the rectum is stretched by feces. The afferent signal through the myenteric plexus activates peristaltic waves of the descending, sigmoid and rectum, forcing the movement of feces towards the anus. At the same time, the internal anal sphincter relaxes. If at this time conscious signals are received to relax the external anal sphincter, then the act of defecation begins.

Adaptive responses of plants to environmental stress

Adaptive syndrome in plants to the effects of stressors: temperature, light, moisture, soil, radiation. Classification of plants depending on the type of adaptation. Physiological, biochemical and environmental basis of nonspecific and specific reactions to stress.

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There are three main groups of factors that cause stress in plants: physical - insufficient or excessive humidity, illumination, temperature, radioactive radiation, mechanical stress; chemical - salts, gases, xenobiotics (herbicides, insecticides, fungicides, industrial waste and etc.); biological - damage by pathogens or pests, competition with other plants, influence of animals, flowering, ripening of fruits. a set of adaptive reactions of the body that are of a general protective nature and arise in response to unfavorable influences of significant strength and duration - stressors. A functional state that develops under the influence of stressors is called stress. The adaptation syndrome was proposed by the Canadian physiologist-endocrinologist Hans Selye (1936). In the development of A. s. Usually there are 3 stages. The 1st - stage of anxiety - lasts from several hours to 2 days and includes two phases - shock and anti-shock, in the latter of which the body’s defense reactions are mobilized. During the 2nd stage of A. s. - stage of resistance - the body’s resistance to various influences is increased. This stage either leads to stabilization of the condition and recovery, or is replaced by the last stage of A. s. - a stage of exhaustion, which can result in the death of the body.

In the first phase, significant deviations in physiological and biochemical processes are observed, both symptoms of damage and a protective reaction appear. The significance of defensive reactions is that they are aimed at eliminating (neutralizing) the damage that occurs. If the exposure is too great, the body dies while still in the alarm stage during the first hours. If this does not happen, the reaction enters the second phase. In the second phase, the body either adapts to new living conditions, or the damage intensifies. With the slow development of unfavorable conditions, the body adapts to them more easily. After the end of the adaptation phase, plants grow normally in unfavorable conditions in an adapted state with a generally reduced level of processes. During the phase of damage (exhaustion, death), hydrolytic processes are intensified, energy-producing and synthetic reactions are suppressed, and homeostasis is disrupted. When the stress intensity exceeds the threshold value for the organism, the plant dies. When the stress factor ceases and environmental conditions normalize, reparation processes are activated, i.e., restoration or elimination of damage. The adaptation process (adaptation in the broad sense) occurs constantly and “adjusts” the body to changes in the external environment within the limits of natural fluctuations in factors. These changes can be both nonspecific and specific. Nonspecific are the same type of reactions of the body to the action of different stressors or different organisms to the same stress factor. Specific responses include responses that differ qualitatively depending on the factor and genotype. The most important nonspecific response of cells to stressors is the synthesis of special proteins.

Stress is a general nonspecific adaptive reaction of the body to the action of any unfavorable factors. There are three main groups of factors that cause stress in plants: physical - insufficient or excessive humidity, illumination, temperature, radioactive radiation, mechanical stress; chemical - salts, gases, xenobiotics (herbicides, insecticides, fungicides, industrial waste, etc.); biological - damage by pathogens or pests, competition with other plants, influence of animals, flowering, ripening of fruits.

Adaptation (adaptation) of a plant to specific environmental conditions is ensured through physiological mechanisms (physiological adaptation), and in a population of organisms (species) - through the mechanisms of genetic variability, heredity and selection (genetic adaptation). Environmental factors can change naturally and randomly. Regularly changing environmental conditions (change of seasons) develop genetic adaptation in plants to these conditions. Adaptation is the process of adaptation of living organisms to certain environmental conditions. The following types of adaptation exist:

1. Adaptation to climatic and other abiotic factors (leaf loss, cold resistance of conifers).

2. Adaptation to obtaining food and water (long roots of plants in the desert).

4. Adaptation that ensures the search and attraction of a partner in animals and pollination in plants (smell, bright color in flowers).

5. Adaptation to migration in animals and seed dispersal in plants (wings on seeds for wind transfer, spines on seeds).

Various plant species ensure resistance and survival in unfavorable conditions in three main ways: through mechanisms that allow them to avoid adverse effects (dormancy, ephemerals, etc.); through special structural devices; thanks to physiological properties that allow them to overcome the harmful influence of the environment. Annual agricultural plants in temperate zones, completing their ontogenesis in relatively favorable conditions, overwinter in the form of resistant seeds (dormant state). Many perennial plants overwinter in the form of underground storage organs (bulbs or rhizomes), protected from freezing by a layer of soil and snow. Fruit trees and shrubs in temperate zones shed their leaves to protect themselves from the winter cold.

Protection from unfavorable environmental factors in plants is provided by structural adaptations, features of the anatomical structure (cuticle, crust, mechanical tissues, etc.), special protective organs (stinging hairs, spines), motor and physiological reactions, production of protective substances (resins, phytoncides) , toxins, protective proteins).

Structural adaptations include small leaves and even the absence of leaves, a waxy cuticle on the surface of the leaves, their dense drooping and submerged stomata, the presence of succulent leaves and stems that retain water reserves, erectoid or drooping leaves, etc. Plants have various physiological mechanisms that allow them to adapt to unfavorable conditions environment. This is the self-type of photosynthesis of succulent plants, which minimizes water loss and is extremely important for the survival of plants in the desert, etc. ways for plants to survive in the steppe

It is known that the vast majority of steppe plants are characterized by the development of strong pubescence on stems, leaves, and sometimes even flowers. Because of this, the steppe grass has a dull, grayish or bluish color, contrasting with the bright emerald green of meadow communities. Examples of widespread plant species with a bluish waxy coating include many representatives of the genus Euphorbia. A reduction in water consumption is also facilitated by a general reduction in the evaporating surface, which is achieved through the development of narrow leaf blades in many steppe grasses and sedges, which, moreover, in dry weather can fold along , reducing the evaporating surface. A similar property has been noted, in particular, in some types of feather grass. The reduction of the evaporating surface in many steppe plants is also achieved due to strongly dissected leaf blades. A similar phenomenon can be observed when comparing many closely related species of Apiaceae, as well as in wormwood from the Asteraceae family. A number of plants solve the problem of lack of moisture by developing deep root systems, which allow them to receive water from deeper soil horizons and thus maintain relative independence from sudden changes in moisture content that occur during the growing season. This group includes many steppe plants - alfalfa, some astragalus, kermeks, as well as a number of species from the Asteraceae family

The ability of a plant to tolerate the effects of unfavorable factors and produce offspring under such conditions is called resistance or stress tolerance. Adaptation (Latin adaptio - adaptation, adjusting) is a genetically determined process of the formation of protective systems that ensure increased stability and the course of ontogenesis in previously unfavorable conditions. Adaptation includes all processes (anatomical, morphological, physiological, behavioral, population, etc.) However, the key factor is the time given to the body to respond. The more time given to respond, the greater the choice of possible strategies.

In the event of a sudden impact of an extreme factor, the response must follow immediately. In accordance with this, three main adaptation strategies are distinguished: evolutionary, ontogenetic and urgent.

Evolutionary (phylogenetic) adaptations are adaptations that arise during the evolutionary process (phylogeny) based on genetic mutations, selection and are inherited.

An example is the anatomical and morphological features of plants living in arid hot deserts globe, as well as in saline areas (adapted to moisture deficiency). Biorhythms are the body's biological clock. Most biological rhythms in plants, animals and humans were developed during the evolution of life on Earth under the influence of various environmental factors, primarily cosmic radiation, electromagnetic fields, etc.

Phylogenetic adaptation is a process that lasts over the lives of several generations, and for this reason alone, according to Yu. Malov, it cannot be a property of one individual organism. Homeostasis of an organism as a basic property is the result of phylogenetic adaptation. The uniformity of representatives of the human species is manifested not in the strict similarity of the morphological and functional characteristics of individual individuals, but in their correspondence external conditions environment. The difference in the structure of organs and tissues is not yet a negation of the norm. It is important whether this structure and its functions correspond to variations in the external environment. If the structure corresponds to fluctuations in external factors, then it ensures the vitality of the organism and determines its health. The content of the concept of adaptation covers not only the ability of living systems to reflect, through change, environmental factors, but also the ability of these systems, in the process of interaction, to create within themselves mechanisms and models of active change and transformation of the environment in which they live.

genotypic adaptation - selection of hereditarily determined (change in genotype) increased adaptability to changed conditions (spontaneous mutagenesis), phenotypic adaptation - with this selection, variability is limited by the reaction norm determined by a stable genotype.

Ontogenetic, or phenotypic, adaptations ensure the survival of a given individual. They are associated with genetic mutations and are not inherited. The formation of such adaptations takes a relatively long time, so they are sometimes called long-term adaptations. A classic example of such adaptations is the transition of some C3 plants to the CAM type of photosynthesis, which helps save water, in response to salinity and severe water deficit.

Ontogenetic adaptation is the ability of an organism to adapt in its individual development to changing external conditions. The following subtypes are distinguished: genotypic adaptation - selection of hereditarily determined (change in genotype) increased adaptability to changed conditions (spontaneous mutagenesis) phenotypic adaptation - with this selection, variability is limited by the reaction norm determined by a stable genotype. Ontogenetic or phenotypic adaptations ensure the survival of a given individual. They are associated with genetic mutations and are not inherited. A classic example of such adaptations is the transition of some C3 plants to the CAM type of photosynthesis, which helps save water, in response to salinity and severe water deficiency. In plants, the source of adaptation can also be non-hereditary adaptive reactions - modifications. The ontogeny of an individual begins from the moment of its formation. This event in an individual can be the germination of a spore, the formation of a zygote, the beginning of fragmentation of the zygote, the emergence of an individual in one way or another during vegetative reproduction (sometimes the beginning of ontogenesis is attributed to the formation of initial cells, for example, oogonia). During ontogenesis, growth, differentiation and integration of parts of the developing organism occur. The ontogeny of an individual can end with its physical death or its reproduction (in particular, during reproduction by division). Each organism during individual development represents whole system Consequently, ontogenesis is an integral process that cannot be decomposed into simple component parts without loss of quality. The degree of possible variability during the implementation of a genotype is called the reaction norm and is expressed by the totality of possible phenotypes when different conditions environment. This determines the so-called ontogenetic adaptation, which ensures the survival and reproduction of organisms, sometimes even with significant changes in the external environment. Moisture and shade tolerance, heat resistance, cold resistance and other ecological characteristics of specific plant species were formed in the course of evolution as a result long acting appropriate conditions. Thus, heat-loving plants and short-day plants are characteristic of southern latitudes, while plants that are less demanding of heat and long-day plants are characteristic of northern latitudes.

Urgent adaptation, which is based on the formation and functioning of shock defense systems, occurs with rapid and intense changes in living conditions. These systems provide only short-term survival under the damaging influence of a factor and thereby create conditions for the formation of more reliable long-term adaptation mechanisms. Shock defense systems include, for example, the heat shock system, which is formed in response to a rapid increase in temperature, or the SOS system, the signal for which is triggered by DNA damage.

Urgent adaptation is the body’s immediate response to the influence of an external factor. Long-term adaptation is a gradually developing response of the body to the action of an external factor. The first, initial, provides imperfect adaptation. It begins from the moment of action of the stimulus and is carried out on the basis of existing functional mechanisms (for example, increased heat production during cooling).

During the adaptation process, the plant goes through two different stages:

1) fast initial response;

2) a significantly longer stage associated with the formation of new isoenzymes or stress proteins that ensure metabolism under changed conditions.

The rapid primary response of a plant to a damaging influence is called a stress response, and the phase that follows is called specialized adaptation. When the stressor ceases, the plant enters a recovery state.

According to the degree of adaptation of plants to conditions of extreme heat deficiency, three groups can be distinguished:

1) non-cold-resistant plants - they are severely damaged or killed at temperatures that have not yet reached the freezing point of water. Death is associated with inactivation of enzymes, disruption of the exchange of nucleic acids and proteins, membrane permeability and cessation of the flow of assimilates. These are rain plants tropical forests, algae of warm seas;

2) non-frost-resistant plants - tolerate low temperatures, but die as soon as ice begins to form in the tissues. With the onset of the cold season, the concentration of osmotically active substances in the cell sap and cytoplasm increases, which lowers the freezing point to - (5-7) ° C. The water in the cells can cool below freezing without immediately forming ice. The supercooled state is unstable and most often lasts several hours, which, however, allows plants to tolerate frost. These are some evergreen subtropical plants - laurels, lemons, etc.;

3) ice-resistant, or frost-resistant, plants - grow in areas with a seasonal climate, with cold winters. During severe frosts, the aboveground organs of trees and shrubs freeze, but nevertheless remain viable, since crystalline ice does not form in the cells. Plants are prepared to withstand frost gradually, undergoing preliminary hardening after the growth processes are completed. Hardening consists of the accumulation in cells of sugars (up to 20-30%), carbohydrate derivatives, some amino acids and other protective substances that bind water. At the same time, the frost resistance of cells increases, since bound water is more difficult to draw off by ice crystals formed in the extracellular spaces.

Thaws in the middle, and especially at the end of winter, cause a rapid decrease in plant resistance to frost. After winter dormancy ends, hardening is lost. Spring frosts that come suddenly can damage shoots that have begun to grow and especially flowers, even in frost-resistant plants.

Based on the degree of adaptation to high temperatures, we can distinguish the following groups plants:

1) non-heat-resistant plants are damaged already at +(30-40)°C (eukaryotic algae, aquatic flowering plants, terrestrial mesophytes);

2) heat-tolerant plants tolerate half-hour heating up to + (50-60) ° C (plants of dry habitats with strong insolation - steppes, deserts, savannas, dry subtropics, etc.).

Some plants are regularly affected by fires, when temperatures briefly rise to hundreds of degrees. Fires are especially common in savannas, dry hardleaf forests and shrublands such as chaparral. There is a group of pyrophytic plants that are resistant to fires. Savannah trees have a thick crust on their trunks, impregnated with fire-resistant substances that reliably protect internal tissues. The fruits and seeds of pyrophytes have thick, often lignified integuments that crack when scorched by fire.

Heat resistance (heat tolerance) - the ability of plants to tolerate high temperatures and overheating. This is a genetically determined trait. Based on heat resistance, there are three groups of plants.

Heat-resistant - thermophilic blue-green algae and bacteria from hot mineral springs, capable of withstanding temperature increases of up to 75-100°C. The heat resistance of thermophilic microorganisms is determined by a high level of metabolism, an increased content of RNA in cells, and the resistance of cytoplasmic proteins to thermal coagulation.

Heat-tolerant - plants of deserts and dry habitats (succulents, some cacti, representatives of the Crassulaceae family) that can withstand heating by sunlight up to 50-65°C. The heat resistance of succulents is largely determined by the increased viscosity of the cytoplasm and the content of bound water in the cells, and reduced metabolism.

Heat-resistant - mesophytic and aquatic plants. Mesophytes of open places tolerate short-term temperatures of 40-47°C, shaded places - about 40-42°C, aquatic plants can withstand temperature increases up to 38-42°C. Among agricultural plants, the most heat-tolerant are heat-loving plants of southern latitudes (sorghum, rice, cotton, castor beans, etc.).

Many mesophytes tolerate high air temperatures and avoid overheating due to intense transpiration, which reduces the temperature of the leaves. More heat-resistant mesophytes are characterized by increased cytoplasmic viscosity and enhanced synthesis of heat-resistant enzyme proteins.

Heat resistance largely depends on the duration of high temperatures and their absolute value. Most agricultural plants begin to suffer when temperatures rise to 35-40°C. At these and higher temperatures, the normal physiological functions of the plant are inhibited, and at a temperature of about 50°C, protoplasm coagulates and cells die.

Exceeding the optimal temperature level leads to partial or global denaturation of proteins. This causes the destruction of protein-lipid complexes of the plasmalemma and other cell membranes, leading to the loss of osmotic properties of the cell.

When exposed to high temperatures, the synthesis of stress proteins (heat shock proteins) is induced in plant cells. Plants in dry, bright habitats are more resistant to heat than shade-loving ones.

Heat resistance is largely determined by the phase of plant growth and development. High temperatures cause the greatest harm to plants in the early stages of their development, since young, actively growing tissues are less stable than old and “dormant” ones. Resistance to heat varies among different plant organs: underground organs are less resistant, shoots and buds are more resistant.

10 . Physiological-biochemical basics nonspecific And specific reactions on stress

Nonspecific are the same type of reactions of the body to the action of different stressors or different organisms to the same stress factor. Specific responses include responses that differ qualitatively depending on the factor and genotype.

The primary nonspecific processes occurring in plant cells under the influence of any stressors include the following:

1. Increased membrane permeability, depolarization of the membrane potential of the plasmalemma.

2. Entry of calcium ions into the cytoplasm from cell walls and intracellular compartments (vacuole, endoplasmic reticulum, mitochondria).

3. Shift the pH of the cytoplasm to the acidic side.

4. Activation of the assembly of actin microfilaments of the cytoskeleton, resulting in increased viscosity and light scattering of the cytoplasm.

5. Increased oxygen absorption, accelerated consumption of ATP, development of free radical processes.

6. Increasing the content of the amino acid proline, which can form aggregates that behave like hydrophilic colloids and contribute to the retention of water in the cell. Proline can bind to protein molecules, protecting them from denaturation.

7. Activation of the synthesis of stress proteins.

8. Increased activity of the proton pump in the plasmalemma and, possibly, in the tonoplast, preventing unfavorable shifts in ionic homeostasis.

9. Strengthening the synthesis of ethylene and abscisic acid, inhibition of division and growth, absorption activity of cells and other physiological processes occurring under normal conditions.

Cross or cross adaptations are adaptations in which the development of resistance to one factor increases resistance to a concomitant one.

In relation to light, all plants, including forest trees, are divided into the following ecological groups:

heliophytes (light-loving), requiring a lot of light and able to tolerate only slight shading (light-loving include almost all cacti and other succulents, many representatives of tropical origin, some subtropical shrubs) pine, wheat, larch (powerful cuticle, many stomata);

sciophytes (shade-loving) - on the contrary, content with insignificant lighting and can exist in the shade (shade-tolerant include various conifers, many ferns, some decorative foliage plants);

shade-tolerant (facultative heliophytes).

Heliophytes. Light plants. Inhabitants of open habitats: meadows, steppes, upper layers of forests, early spring plants, many cultivated plants.

small leaf sizes; Seasonal dimorphism occurs: in spring the leaves are small, in summer they are larger;

leaves are located at a large angle, sometimes almost vertically;

leaf blade shiny or densely pubescent;

form sparse stands.

Sciophytes. Can't stand strong light. Habitats: lower darkened tiers; inhabitants of the deep layers of reservoirs. First of all, these are plants growing under the forest canopy (oxalis, kostyn, snot).

Characterized by the following features:

leaves are large, tender;

dark green leaves;

The so-called leaf mosaic is characteristic (that is, a special arrangement of leaves in which the leaves do not obscure each other as much as possible).

Shade-tolerant. They occupy an intermediate position. They often grow well in normal lighting conditions, but can also tolerate dark conditions. According to their characteristics, they occupy an intermediate position.

The reasons for this difference must be sought, first of all, in the specific characteristics of chlorophyll, then in the different architectonics of the species (in the structure of shoots, the location and shape of leaves). By distributing the forest trees in accordance with their need for light, which is manifested in their competition when they grow together, and placing the most light-loving ones first, we will obtain approximately the following rows.

1) Larch, birch, aspen, alder

2) ash, oak, elm

3) spruce, linden, hornbeam, beech, fir.

It is a remarkable and biologically important fact that almost all trees in their youth can tolerate more shading than at a more mature age. It should further be noted that the ability to tolerate shading is to a certain extent dependent on soil fertility.

Plants are divided into:

1. long-day 16-20 hours. Day length - temperate zone, northern latitude,

2. short-day night is equal to day - equatorial latitudes,

3. neutral - American maple, dandelion, etc.

Shade-tolerant plants, plants (mainly woody, many herbaceous under the canopy of deciduous trees, greenhouses, etc.) that tolerate some shading, but develop well in direct sunlight. Physiologically T. r. characterized by a relatively low intensity of photosynthesis. Leaves of T. r. have a number of anatomical and morphological features: the columnar and spongy parenchyma are poorly differentiated, the cells contain a small number (10-40) of chloroplasts, the surface area of ​​which varies between 2-6 cm2 per 1 cm2 of leaf area. A number of plants under the forest canopy (for example, hoofweed, gooseberry, etc.) in early spring, before the leaves of the tree layer bloom, are physiologically light-loving, and in the summer, when the canopy is closed, they are shade-tolerant.

Shade-tolerant plants are shade-tolerant plants that grow primarily in shady habitats (unlike light-loving plants, heliophytes), but also grow well in open areas with more or less direct sunlight (unlike shade-loving plants, sciophytes). Shade-tolerant plants are considered in plant ecology as an intermediate group between heliophytes and sciophytes; they are defined as facultative heliophytes.

Features of the morphology and physiology of shade-tolerant plants

The mosaic arrangement of leaves helps to better capture diffused light. Sugar maple leaves

Shade-tolerant plants are characterized by a relatively low intensity of photosynthesis. Their leaves differ from the leaves of heliophytes in a number of important anatomical and morphological characteristics. In the leaves of shade-tolerant plants, columnar and spongy parenchyma are usually poorly differentiated; characterized by increased intercellular spaces. The epidermis is quite thin, single-layered; epidermal cells may contain chloroplasts (which is never found in heliophytes). The cuticle is usually thin. Stomata are usually located on both sides of the leaf with a slight predominance on the reverse side (in light-loving plants, as a rule, there are no stomata on the front side or are located predominantly on the reverse side). Compared to heliophytes, shade-tolerant plants have a significantly lower content of chloroplasts in leaf cells - on average from 10 to 40 per cell; the total surface of the leaf chloroplasts does not significantly exceed its area (2-6 times; whereas in heliophytes the excess is tens of times).

Some shade-tolerant plants are characterized by the formation of anthocyanin in cells when growing in bright sun, which gives a reddish or brownish color to the leaves and stems, which is uncharacteristic in natural habitat conditions. Others have paler leaves when grown in direct sunlight.

The appearance of shade-tolerant plants also differs from light-loving ones. Shade-tolerant plants typically have wider, thinner and softer leaves to capture more indirect sunlight. They are usually flat and smooth in shape (whereas in heliophytes, folding and tuberculation of leaves is often found). Characterized by a horizontal arrangement of foliage (in heliophytes, leaves are often located at an angle to the light) and a leaf mosaic. Forest herbs are usually elongated, tall, and have an elongated stem.

Many shade-tolerant plants have high plasticity of their anatomical structure depending on the light level (primarily this concerns the structure of the leaves). For example, in beech, lilac, and oak, leaves formed in the shade usually have significant anatomical differences from leaves grown in bright sunlight.

Shade-tolerant plants include some root vegetables (radish, turnip) and herbs (parsley, lemon balm, mint). The common cherry is relatively shade-tolerant (one of the few shade-tolerant fruit trees); Some berry bushes are shade-tolerant (currants, blackberries, some varieties of gooseberries) and herbaceous plants(garden strawberries, lingonberries).

Some shade-tolerant plants are valuable forage crops. The vetch grown for these purposes is also used as green manure.

15. Photophilous plants And their anatomical and physiological peculiarities

Light-loving plants, heliophytes, plants that grow in open areas and cannot tolerate prolonged shading; for normal growth they need intense solar or artificial radiation. Adult plants are more light-loving than young ones. K S. r. include both herbaceous (large plantain, water lily, etc.) and woody (larch, acacia, etc.) plants, early spring plants - steppes and semi-deserts, and cultivated plants - corn, sorghum, sugar cane, etc. have a number of anatomical, morphological and physiological features: relatively thick leaves with small-celled columnar and spongy parenchyma and a large number of stomata. Leaf cells contain from 50 to 300 small chloroplasts, the surface of which is tens of times greater than the surface of the leaf. Compared to shade-tolerant plants, the leaves of S. r. contain more chlorophyll per unit surface area and less per unit leaf mass. A characteristic physiological sign of S. r. - high intensity of photosynthesis (heliophytes).

Plants that cannot tolerate prolonged shading. These are plants of open habitats: steppe and meadow grasses, rock lichens, plants of alpine meadows, coastal and aquatic (with floating leaves), early spring herbaceous plants of deciduous forests.

Light-loving trees include: saxaul, honey locust, black locust, albizia, birch, larch, Atlas and Lebanese cedars, Scots pine, common ash, Japanese sophora, white mulberry, squat elm, Amur velvet, walnut, black and white poplars, aspen , common oak; for shrubs - angustifolia, amorpha, oleander, etc. Dissected leafy, golden, white variegated forms of tree species and shrubs are more demanding of light. Light-loving plants usually have smaller leaves than shade-tolerant plants. Their leaf blade is located vertically or at a large angle to the horizontal plane, so that during the day the leaves receive only sliding rays. This arrangement of leaves is typical for eucalyptus, mimosa, acacia, and many steppe herbaceous species. The surface of the leaf is shiny (laurel, magnolia), covered with a light waxy coating (cacti, milkweed, Crassulaceae) or densely pubescent, there is a thick cuticle. Internal structure The leaf is distinguished by its characteristics: the palisade parenchyma is well developed not only on the upper, but also on the underside of the leaf, the mesophyll cells are small, without large intercellular spaces, the stomata are small and numerous. light-loving plants are characterized by a high intensity of photosynthesis, slowing down growth processes, and are more sensitive to lack of light. Light requirements change with the age of the plant and depend on environmental conditions. The same species is more shade-tolerant when young. When a tree species moves (in cultivation) from warm regions to colder ones, its need for light increases, which is also influenced by the nutritional conditions of the plants. On fertile soil, plants can develop with less intense light; on poor soil, the need for light increases.

16. Shade-loving plants And their anatomical and physiological peculiarities

Plants that do not tolerate strong light. These include, for example, many forest herbs (oxalis, maynik, etc.). When cutting down forest, once exposed to light, they show signs of oppression and die. The highest intensity of photosynthesis is observed in such plants under moderate lighting.

Most agricultural plants begin to suffer when temperatures rise to 35-40°C. At these and higher temperatures, the normal physiological functions of the plant are inhibited, and at a temperature of about 50°C, protoplasm coagulates and cells die. Exceeding the optimal temperature level leads to partial or global denaturation of proteins. This causes the destruction of protein-lipid complexes of the plasmalemma and other cell membranes, leading to the loss of osmotic properties of the cell. As a result, disorganization of many cell functions and a decrease in the speed of various physiological processes are observed. Thus, at a temperature of 20°C, all cells undergo the process of mitotic division, at 38°C, mitosis is observed in every seventh cell, and an increase in temperature to 42°C reduces the number of dividing cells by 500 times (one dividing cell per 513 non-dividing cells). At maximum temperatures, flow rate organic matter respiration exceeds its synthesis, the plant becomes poor in carbohydrates, and then begins to starve. This is especially pronounced in plants of more temperate climates (wheat, potatoes, many garden crops).

Photosynthesis is more sensitive to high temperatures than respiration. At suboptimal temperatures, plants stop growth and photoassimilation, which is caused by disruption of enzyme activity, increased respiratory gas exchange, decreased energy efficiency, increased hydrolysis of polymers, in particular protein, and poisoning of protoplasm by decomposition products harmful to the plant (ammonia, etc.). In heat-resistant plants under these conditions, the content of organic acids that bind excess ammonia increases.

A way to protect against overheating can be enhanced transpiration provided by a powerful root system. As a result of transpiration, the temperature of plants sometimes decreases by 10-15°C. Withering plants, with closed stomata, die more easily from overheating than plants that are sufficiently supplied with water. Plants tolerate dry heat more easily than humid heat, since during heat and high air humidity, the regulation of leaf temperature due to transpiration is limited.

An increase in temperature is especially dangerous during strong insolation. To reduce the intensity of exposure to sunlight, plants place their leaves vertically, parallel to its rays (erectoid). In this case, chloroplasts actively move in the mesophyll cells of the leaf, as if escaping excess insolation. Plants have developed a system of morphological and physiological adaptations that protect them from thermal damage: light coloring of the surface, reflecting insolation; folding and curling leaves; pubescence or scales that protect underlying tissues from overheating; thin layers of cork tissue that protect the phloem and cambium; greater thickness of the cuticular layer; high content of carbohydrates and low content of water in the cytoplasm, etc. In field conditions, the combined effect of high temperatures and dehydration is especially destructive. With prolonged and deep wilting, not only photosynthesis is inhibited, but also respiration, which causes a disruption of all the basic physiological functions of the plant. High temperatures cause the greatest harm to plants in the early stages of their development, since young, actively growing tissues are less stable than old and “dormant” tissues. Resistance to heat varies among different plant organs: underground organs are less resistant, shoots and buds are more resistant. Plants respond very quickly to heat stress with inductive adaptation. During the formation of generative organs, the heat resistance of annual and biennial plants decreases. The harmful effects of elevated temperatures are one of the most important reasons for a significant reduction in early spring crop yields when sowing is delayed. For example, in wheat, in the tillering phase, differentiation of spikelets occurs in the growth cone. High soil and air temperatures lead to damage to the growth cone, speed up the process and shorten the time for passing stages IV-V, resulting in a decrease in the number of spikelets per ear, as well as the number of flowers per spikelet, which leads to a decrease in yield.

The development of plants, their growth and other physiological processes occur under certain temperature conditions. Moreover, each plant type has temperature minimums, optimums and maximums for each physiological process. Therefore, heat is an important environmental factor that determines the life of an individual plant, the distribution of plant species among earth's surface, formation of vegetation types.

For each type of plant, it is necessary to distinguish between two temperature boundaries: minimum and maximum, i.e., temperatures at which life processes in plants cease, and optimal temperature, most favorable for the life of plants. For various physiological processes (photosynthesis, respiration, growth) in the same plant species, the position of these boundaries is not the same. It is also different for phenological phases of tree species. For example, shoot growth in spruce and fir begins at temperatures from +7 to +10°, and flowering begins at higher temperatures, above +10°. Species such as alder, aspen, hazel, and willow bloom at lower temperatures, and their shoots grow much later at higher temperatures.

It is characteristic of all life processes of plants that optimal temperatures for them it is closer to the maximum than to the minimum. If pine growth occurs within the temperature range from +7 to +34°, then the optimal temperature is from + 25 to +28°.

The seeds of many plants, including trees, require prior exposure to low temperatures for timely and normal germination. The stratification of seeds of some woody plants is based on this principle: ash, linden, euonymus, hawthorn. Leaf and flower buds in woody plants also bloom faster after exposure to low temperatures.

Plants tolerate higher temperatures better if they contain little water (especially plant seeds and spores) or if they are dormant (desert plants).

Protection against overheating of plants is transpiration, which significantly lowers the body temperature of the plant. The accumulation of salts in plant cells also increases the resistance of their protoplasm to coagulation under the influence of high temperature. This is especially common in desert plants (saxaul, solyanka). In seedlings and annual seedlings of woody plants heat In addition to drying out, it sometimes causes the root neck to fall off.

The minimum temperature has a large amplitude for various types plants. Thus, some tropical plants are damaged by cold even at a temperature of +5°, and die below zero (for example, some orchids). The cause of death of plants from cold is mainly the loss of water by cells. Ice crystals formed in the intercellular spaces draw water from the cells, drying them out and destroying them. Therefore, plants and their parts that contain little water tolerate low temperatures better (for example, lichens, dry seeds and plant spores).

In many cases, it is not the low temperature itself that is harmful to the plant, which leads to freezing, but rapid thawing or alternating thawing with freezing. However, some plants, such as sphagnum mosses, although they contain a lot of water, can quickly freeze and thaw without harm to life.

Some tree species can tolerate very low winter temperatures (-40 - 45°) without harm (pine, larch, Siberian cedar, birch, aspen), while other species are damaged. However, the nature and degree of damage varies. In Norway spruce, annual needles and even dormant buds are partially or completely damaged. Dormant buds of oak, ash, and Norway maple die; in this case, the trees remain without leaves for a long time, until the end of June, until the dormant buds sprout and restore normal foliage of the crown. Sometimes dormant buds remain undamaged, but the cambium of the trunk and branches is very damaged by frost, which is especially dangerous, since after this the buds bloom in the spring, but soon the young shoots wither and the tree dies completely. This is observed in some poplars, young black alder trees, and apple trees.

When the outer parts of the trunk are overcooled during sharp drops in temperature in winter, sometimes a longitudinal rupture of the surface of the trunk occurs and frost cracks form, which weakens the tree and spoils the quality of the wood. Coniferous trees sometimes suffer from early spring heating, when thawed needles begin to evaporate water, but water does not yet flow from the frozen parts of the trunk and roots. This phenomenon is called sunburn, it leads to browning of younger, usually one-year-old needles.

Trees react differently to late spring frosts, which occur at the beginning of the growing season, when the temperature in the lower layers of the atmosphere (up to a height of 3 - 4 m) at night drops to -3 - 5°. Then, in young trees, the shoots that have just appeared after bud break are damaged to such an extent that sometimes they die completely; These species include spruce, fir, oak, and ash.

In relation to heat, woody plants growing naturally or bred in the USSR are classified as follows:

1. Completely cold-resistant, completely undamaged by low winter temperatures, withstanding frosts down to -45-50°, and some even lower, not damaged by late spring frosts. Such woody plants include Siberian and Dahurian larches, Scots pine, Siberian spruce, Siberian and dwarf cedars, common juniper, aspen, downy and warty birch, gray alder, mountain ash, goat willow, and sweet poplar.

2. Cold-resistant, withstanding severe winters, but damaged by very severe frosts (below - 40°). In some, needles are damaged, in others - dormant buds. Some species of this group are damaged by late spring frosts. These include Norway spruce, Siberian fir, black alder, small-leaved linden, elm, elm, Norway maple, black and white poplars.

3. Relatively thermophilic with a longer growing season, as a result of which their annual shoots do not always have time to become lignified and are partially or completely damaged by frost; all plants are severely damaged by very low winter temperatures; many of them are damaged by late spring frosts. These species include summer and winter oaks, common ash, large-leaved linden, hornbeam, birch bark, velvet tree, Manchurian walnut, euonymus, and Canadian poplar.

4. Heat-loving with an even longer growing season, their shoots often do not ripen and die from frost. In severe, prolonged frosts, the entire aerial part of such plants dies, and its renewal occurs from dormant buds at the neck of the root. These species include pyramidal poplar, walnut, real chestnut, mulberry, and white acacia.

5. Very heat-loving, which do not tolerate or do not tolerate prolonged frosts down to -10-15°. At this temperature, over the course of several days, they either completely die or are severely damaged; these include true cedar, cypress, eucalyptus, citrus fruits, cork oak, grandiflora magnolia, and silk acacia.

It is impossible to draw a sharp boundary between these groups; many woody plants occupy an intermediate position. An increase in cold resistance of the same species also depends on the growing conditions. However, all this does not exclude the need for comparative characteristics and classification of woody plants in relation to heat.

ADAPTATION

Adaptation- a systemic, stage-by-stage process of adaptation of the body to factors of unusual strength, duration or nature (stress factors).

The adaptation process is characterized by phase changes in life activity, ensuring an increase in the body’s resistance to the factor affecting it, and often to stimuli of a different nature (the phenomenon of cross adaptation). The idea of ​​the adaptation process was first formulated by Selye in 1935-1936. G. Selye distinguished the general and local form of the process.

The general (generalized, systemic) adaptation process is characterized by the involvement of all or most organs and physiological systems of the body in the response.

The local adaptation process is observed in individual tissues or organs during their alteration. However, local adaptation syndrome is also formed with greater or lesser participation of the whole organism.

If the current stress factor is characterized by high (destructive) intensity or excessive duration, then the development of the adaptation process can be combined with disruption of the body’s vital functions, the occurrence of various diseases, or even its death.

The body's adaptation to stress factors is characterized by the activation of specific and nonspecific reactions and processes.

Specific component the development of adaptation ensures that the body adapts to the action of a specific factor (for example, hypoxia, cold, physical activity, a significant excess or deficiency of a substance, etc.).

Non-specific component The adaptation mechanism consists of general, standard, nonspecific changes in the body that occur when exposed to any factor of unusual strength, nature or duration. These changes are described as stress.

Etiology of adaptation syndrome

Causes adaptation syndrome is divided into exogenous and endogenous. Most often, adaptation syndrome is caused by exogenous agents of various natures.

Exogenous factors:

♦ Physical: significant fluctuations in atmospheric pressure, temperature, significantly increased or decreased physical activity, gravitational overloads.

♦ Chemical: deficiency or increased oxygen content in the inhaled air, fasting, lack or excess of fluid entering the body, intoxication of the body with chemicals.

♦ Biological: infection of the body and intoxication with exogenous biologically active substances.

Endogenous causes:

♦ Insufficiency of functions of tissues, organs and their physiological systems.

♦ Deficiency or excess of endogenous biologically active substances (hormones, enzymes, cytokines, peptides, etc.).

Conditions, influencing the occurrence and development of adaptation syndrome:

The state of reactivity of the body. Both the possibility (or impossibility) of its occurrence and the peculiarities of the dynamics of this process largely depend on it.

Specific conditions under which pathogenic factors act on the body (for example, high air humidity and the presence of wind aggravate the pathogenic effect of low temperature; insufficient activity of liver microsomal enzymes leads to the accumulation of toxic metabolic products in the body).

Stages of adaptation syndromeEMERGENCY ADAPTATION STAGE

The first stage of adaptation syndrome is urgent (emergency) adaptation- consists in mobilizing pre-existing compensatory, protective and adaptive mechanisms in the body. This is manifested by a triad of regular changes.

Significant activation of the individual’s “research” behavioral activity aimed at obtaining maximum information about the emergency factor and the consequences of its action.

Hyperfunction of many body systems, but mainly those that directly (specifically) provide adaptation to a given factor. These systems (physiological and functional) are called dominant.

Mobilization of organs and physiological systems (cardiovascular, respiratory, blood, IBN, tissue metabolism, etc.), which respond to the influence of any emergency factor for a given organism. The combination of these reactions is designated as a nonspecific - stress component of the mechanism of adaptation syndrome.

The development of urgent adaptation is based on several interrelated mechanisms.

♦ Activation of the nervous and endocrine systems. Leads to an increase in the blood and other body fluids of hormones and neurotransmitters: adrenaline, norepinephrine, glucagon, gluco- and mineralocorticoids, thyroid hormones, etc. They stimulate catabolic processes in cells, the function of organs and tissues of the body.

♦ Increased content in tissues and cells of various local “mobilizers” of functions - Ca 2+, a number of cytokines, peptides, nucleotides and others. They activate protein kinases and the processes catalyzed by them (lipolysis, glycolysis, proteolysis, etc.).

♦ Changes in the physicochemical state of the cell membrane apparatus, as well as enzyme activity. This is achieved due to the intensification of SPOL, activation of phospholipases, lipases and proteases, which facilitates the implementation of transmembrane processes, changes the sensitivity and number of receptor structures.

♦ Significant and long-term increase in organ function, consumption of metabolic substrates and high-energy nucleotides, relative lack of blood supply to tissues. This may be accompanied by the development of dystrophic changes and even necrosis. As a result, at the stage of urgent adaptation, the development of diseases, painful conditions and pathological processes (for example, ulcerative changes in the gastrointestinal tract, arterial hypertension, immunopathological conditions, neuropsychiatric disorders, myocardial infarction, etc.), and even the death of the body is possible.

The biological meaning of reactions developing at the stage of urgent adaptation is to create the conditions necessary for

so that the body “holds out” until the stage of formation of its stable increased resistance to the action of an extreme factor.

The second stage of adaptation syndrome - increased stable resistance, or long-term adaptation of the body to the action of an emergency factor. It includes the following processes.

The formation of a state of resistance of the body both to a specific agent that caused adaptation, and often to other factors.

Increasing the power and reliability of the functions of organs and physiological systems that provide adaptation to a certain factor. In the endocrine glands, effector tissues and organs, an increase in the number or mass of structural elements is observed (i.e., their hypertrophy and hyperplasia). The complex of such changes is designated as a systemic structural trace of the adaptation process.

Elimination of signs of stress reactions and achieving a state of effective adaptation of the body to the extreme factor that caused the adaptation process. As a result, a reliable, stable system of adaptation of the body to changing environmental conditions is formed.

Additional energy and plastic support for cells of dominant systems. This is combined with a limited supply of oxygen and metabolic substrates to other body systems.

With repeated development of the adaptation process, hyperfunction and pathological hypertrophy of the cells of the dominant systems are possible. This leads to disruption of their plastic support, inhibition of the synthesis of nucleic acids and proteins in them, disorders of the renewal of structural elements of cells and their death.

EXHAUSTION STAGE

This stage is optional. When the stage of exhaustion (or wear and tear) develops, the processes underlying it can cause the development of diseases and even the death of the body. Such states are designated as adaptation diseases(more precisely, its violations) - maladjustment. An important and necessary component of the adaptation syndrome is stress. At the same time, in a large number of cases it can develop as an independent process.

STRESS

Stress is a generalized nonspecific response of the body to the influence of various factors of unusual nature, strength or duration.

Stress is characterized by staged nonspecific activation of protective processes and an increase in the general resistance of the body with a possible subsequent decrease in it and the development of pathological processes and reactions.

The causes of stress are the same factors that cause adaptation syndrome (see above).

FEATURES OF STRESS

The impact of any emergency factor causes two interrelated processes in the body:

♦ specific adaptation to this factor;

♦ activation of standard, nonspecific reactions that develop when exposed to any influence unusual for the body (stress itself).

Stress is an essential part of the process of urgent adaptation of the body to the effects of any emergency factor.

Stress precedes the development of the stage of stable resistance of the adaptation syndrome and contributes to the formation of this stage.

With the development of increased resistance of the body to an emergency factor, the disturbance of homeostasis is eliminated, and stress stops.

If for some reason the body’s increased resistance does not develop (and therefore, deviations in the body’s homeostasis parameters persist or even increase), then the state of stress also persists.

Stages of stress

In the process of stress development, the stages of anxiety, resistance and exhaustion are distinguished.

ANXIETY STAGE

The first stage of stress is a general reaction of anxiety.

In response to stress factors, the flow of afferent signals increases, changing the activity of the cortical and subcortical nerve centers regulating the body's vital functions.

In the nerve centers, a program of efferent signals is urgently formed, which is implemented with the participation of nervous and humoral regulatory mechanisms.

Due to this, at the stage of anxiety, the sympathoadrenal, hypothalamic-pituitary-adrenal systems are naturally activated (they play a key role in the development of stress), as well as the endocrine glands (thyroid, pancreas, etc.).

These mechanisms, being a nonspecific component of the urgent (emergency) adaptation stage of the general adaptation syndrome, ensure that the body escapes from the action of a damaging factor or from extreme conditions of existence; formation of increased resistance to altering influences; the necessary level of functioning of the body even with continued exposure to an emergency agent.

At the anxiety stage, the transport of energy, metabolic and plastic resources to the dominant organs increases. A significantly pronounced or prolonged stage of anxiety can cause the development of dystrophic changes, malnutrition and necrosis of individual organs and tissues.

STAGE OF INCREASED RESISTANCE

At the second stage of stress, the functioning of organs and their systems, metabolic rate, levels of hormones and metabolic substrates are normalized. The basis of these changes is hypertrophy or hyperplasia of the structural elements of tissues and organs that ensure the development of increased resistance of the body: endocrine glands, heart, liver, hematopoietic organs and others.

If the cause that caused stress continues to operate, and the above mechanisms become insufficient, the next stage of stress develops - exhaustion.

EXHAUSTION STAGE

This stage of stress is characterized by a disorder of the mechanisms of nervous and humoral regulation, the dominance of catabolic processes in tissues and organs, and disruption of their functioning. Ultimately, the overall resistance and adaptability of the body decreases, and its vital functions are disrupted.

These deviations are caused by a complex of nonspecific pathogenic changes in various organs and tissues of the body.

♦ Excessive activation of phospholipases, lipases and SPOL damages lipid-containing components of cell membranes and associated enzymes. As a result, transmembrane and intracellular processes are disrupted.

♦ High concentrations of catecholamines, glucocorticoids, ADH, STH cause excessive mobilization of glucose, lipids and protein compounds in various tissues. This leads to a deficiency of substances, the development of dystrophic processes and even cell necrosis.

Redistribution of blood flow in favor of the dominant systems. In other organs, hypoperfusion is noted, which is accompanied by the development of dystrophies, erosions and ulcers in them.

A decrease in the effectiveness of the IBN system and the formation of immunodeficiencies under excessively prolonged, severe, and repeated stress.

Types of stress

According to its biological significance, stress can be divided into adaptive and pathogenic.

Adaptive stress

If the activation of the functions of organs and their systems in a given individual under the influence of a stress agent prevents disturbances in homeostasis, then a state of increased resistance of the body can form. In such cases, stress has an adaptive value. When the same extreme factor acts on the body in its adapted state, as a rule, no disturbances in vital activity are observed. Moreover, repeated exposure to a stressor of moderate strength at certain intervals (necessary for the implementation of recovery processes) forms a stable, long-term increased resistance of the body to this and other influences.

The nonspecific adaptive property of repeated action of various stress factors of moderate strength (hypoxia, physical activity, cooling, overheating and others) is used to artificially increase the body's resistance to stress factors and prevent their damaging effects. For the same purpose, courses of so-called nonspecific treatment and prophylactic procedures are conducted: pyrotherapy, dousing with cool or hot water, various shower options, autohemotherapy, physical activity, periodic exposure to moderate hypobaric hypoxia (in pressure chambers), etc.

Pathogenic stress

Excessively prolonged or frequent repeated exposure to a strong stressor on the body that is unable to prevent

disruption of homeostasis can lead to significant disorders of life and the development of extreme (collapse, shock, coma) or even terminal conditions.

Anti-stress mechanisms

In most cases, the development of stress, even significantly pronounced, does not cause damage to organs or disruption of the body’s functioning. Moreover, often the stress itself is quickly eliminated. This means that when exposed to an emergency agent in the body, along with the activation of the stress development mechanism, factors begin to operate that limit its intensity and duration. Their combination is designated as stress-limiting factors, or anti-stress mechanisms of the body.

MECHANISMS OF IMPLEMENTATION OF ANTI-STRESS REACTIONS

Limitation of stress and its pathogenic effects in the body is realized with the participation of a complex of interrelated factors. They are activated at the level of both central regulatory mechanisms and peripheral (executive) organs.

In the brain anti-stress mechanisms are realized with the participation of GABAergic, dopaminergic, opioidergic, serotonergic neurons and, possibly, neurons of other chemical specifications.

In peripheral organs and tissues Pg, adenosine, acetylcholine, and antioxidant protection factors for tissues and organs have a stress-limiting effect. These and other substances prevent or significantly reduce the stress-induced intensification of free radical processes, the release and activation of lysosome hydrolases, and prevent stress-related organ ischemia, ulcerative lesions of the gastrointestinal tract, and degenerative changes in tissues.

Principles of stress correction

Pharmacological correction of stress is based on the principles of optimizing the functions of systems that initiate stress, as well as preventing, reducing or eliminating changes in tissues and organs under conditions of developing stress.

Optimizing the functions of stress-initiating systems body (sympathoadrenal, hypothalamic-pituitary-adrenal). When exposed to stress factors, the development of inadequate reactions is possible: excessive or insufficient. To a large extent, the severity of these reactions depends on their emotional perception.

♦ To prevent inadequate stress reactions, various classes of tranquilizers are used. The latter help eliminate the state of asthenia, irritability, tension, and fear.

♦ In order to normalize the state of stress-initiating systems, drugs are used that block their effects when they are excessively activated (adrenolytics, adrenoblockers, “antagonists” of corticosteroids) or potentiate them when these systems are insufficient (catecholamines, gluco- and mineralocorticoids).

Process correction, developing in tissues and organs under stress, is achieved in two ways.

♦ Activation of central and peripheral anti-stress mechanisms (use of GABA drugs, antioxidants, Pg, adenosine or stimulation of their formation in tissues).

Adjustment disorder- States of subjective distress and emotional disturbance, usually interfering with social functioning and productivity, and occurring during the period of adaptation to a significant life change or stressful life event (including the presence or possibility of a serious physical illness). Stressors can affect integrity social network the patient (loss of loved ones, separation anxiety), the wider system of social support and social values ​​(migration, refugee status). A stressor can affect an individual or also his microsocial environment. In 2013, the name was changed to “Acute Stress Reaction.”

Individual predisposition or vulnerability plays a more important role in the risk of occurrence and development of manifestations of adaptation disorders than in other disorders in F43, but nevertheless it is believed that the condition would not have arisen without the stress factor. Manifestations vary and include depressed mood, anxiety, restlessness (or a mixture of these); feeling unable to cope, plan, or stay in the present situation; as well as some degree of decreased productivity in daily activities. The individual may feel prone to dramatic behavior and aggressive outbursts, but these are rare. However, behavioral disorders (eg, aggressive or dissocial behavior) may also occur, especially in adolescents.

No symptom is so significant or predominant as to suggest a more specific diagnosis. Regressive phenomena in children, such as enuresis or baby talk or thumb sucking, are often part of the symptomatology. If these traits predominate, F43.23 should be used.

The onset is usually within a month after a stressful event or life change, and the duration of symptoms usually does not exceed 6 months (except F43.21 - prolonged depressive reaction due to adjustment disorder). If symptoms persist, the diagnosis should be modified according to the present clinical picture, and any ongoing stress may be coded using one of the ICD-10 Class XX “Z” codes.

Contacts with medical and mental health services due to normal grief reactions that are culturally appropriate for the individual and typically do not exceed 6 months should not be designated by this Class (F) codes, but should be qualified by Class XXI ICD-10 codes such as , Z-71.- (counseling) or Z73.3 (stressful condition not elsewhere classified). Grief reactions of any duration assessed as abnormal due to their form or content should be coded as F43.22, F43.23, F43.24 or F43.25, and those that remain intense and continue for more than 6 months - F43.21 (prolonged depressive reaction due to adaptation disorder).

Diagnostic guidelines

Diagnosis depends on careful assessment of the relationship between:

• form, content and severity of symptoms;
• anamnestic data and personality;
• stressful event, situation and life crisis.

The presence of the third factor must be clearly established and there must be strong, although perhaps suggestive, evidence that the disorder would not have arisen without it. If the stressor is relatively minor and if a temporal relationship (less than 3 months) cannot be established, the disorder should be classified elsewhere according to the presenting features.

Included:

• culture shock;
• grief reaction;
• hospitalism in children.

Other diseases category F43

• separation anxiety disorder in children (F93.0).

If the criteria for adaptation disorders are met, the clinical form or predominant signs must be specified using the fifth character.

• F43.20 Short-term depressive reaction due to adjustment disorder
  • Transient mild depressive state, not exceeding 1 month in duration.
• F43.21 Prolonged depressive reaction due to adaptation disorder
  • Mild depression in response to prolonged exposure to a stressful situation, but lasting no more than 2 years.
• F43.22 Mixed anxiety and depressive reaction due to adaptation disorder
  • Distinct anxiety and depressive symptoms, but not greater than those found in mixed anxiety and depressive disorder (F41.2) or other mixed anxiety disorder (F41.3).
• F43.23 Adaptation disorder with predominant disturbance of other emotions
  • Symptoms are usually several types of emotions such as anxiety, depression, restlessness, tension and anger. Symptoms of anxiety and depression may meet criteria for mixed anxiety and depressive disorder (F41.2) or other mixed anxiety disorder (F41.3), but they are not so prevalent that other more specific depressive or anxiety disorders can be diagnosed. This category should also be used in children when there is regressive behavior such as enuresis or thumb sucking.
• F43.24 Adaptation disorder with predominant behavior disorder
  • The underlying disorder is conduct disorder, which is an adolescent grief reaction leading to aggressive or dissocial behavior.
• F43.25 Mixed disorder of emotions and behavior due to adjustment disorder
  • Both emotional symptoms and behavioral disturbances are prominent characteristics.
• F43.28 Other specific predominant symptoms due to adjustment disorder