THERMOREGULATION is a physiological process that maintains a constant temperature in the body of warm-blooded animals and humans. The constancy of temperature is the result of self-regulation of the body, necessary for normal life. Body temperature depends on heat production and heat loss.

Heat production, i.e., the production of heat in the body, depends on the intensity of metabolism. Heat transfer from the surface of the body external environment carried out in several ways. Vascular heat transfer consists in changing the filling of skin vessels with blood and the rate of its flow due to the expansion or narrowing of the lumen of the vessel. An increase in blood supply enhances heat transfer, and a decrease reduces it. When the temperature environment falls, the blood vessels at the surface of the skin constrict, thereby reducing heat loss through the skin (A). If body temperature is elevated (for example, during illness), the vessels dilate to increase heat transfer (B).

Heat transfer is also carried out due to radiation and evaporation of water with sweat (when sweat evaporates, excess heat is released from the surface of the skin, which ensures normal body temperature). Part of the heat is released with exhaled air, as well as with urine and feces.

Thermoregulation is carried out reflexively. Fluctuations in ambient temperature are perceived by thermoreceptors. IN in large numbers thermoreceptors are located in the skin, in the oral mucosa, upper respiratory tract. Thermoreceptors were found in internal organs, veins, and also in some formations of the central nervous system. Skin thermoreceptors are very sensitive to fluctuations in ambient temperature. They are excited when the temperature of the medium rises by 0.007 ° C and decreases by 0.012 ° C.

Nerve impulses that arise in thermoreceptors travel along afferent nerve fibers to the spinal cord. Along the conducting paths, they reach the visual tubercles, and from them they go to the hypothalamic region and to the cerebral cortex. As a result, there are sensations of heat or cold. In the spinal cord there are centers of some thermoregulatory reflexes. The hypothalamus is the main reflex center for thermoregulation. The anterior hypothalamus controls the mechanisms of physical thermoregulation, i.e. they are the center of heat transfer. The posterior hypothalamus controls chemical thermoregulation and is the center of heat generation. An important role in the regulation of body temperature belongs to the cerebral cortex. The efferent nerves of the thermoregulation center are mainly sympathetic fibers.

The hormonal mechanism, in particular the hormones of the thyroid gland and adrenal glands, is also involved in the regulation of heat transfer. Thyroid hormone thyroxine, increasing the metabolism in the body, increases heat generation. The entry of thyroxine into the blood increases when the body is cooled. The adrenal hormone adrenaline enhances oxidative processes, thereby increasing heat generation. In addition, under the action of adrenaline, vasoconstriction occurs, in particular the vessels of the skin, due to this, heat transfer decreases.

Age features thermoregulation. In children of the first year of life, imperfect mechanisms are observed. As a result, when the ambient temperature drops below 15 ° C, hypothermia of the child's body occurs. In the first year of life, there is a decrease in heat transfer through thermal conductivity and heat radiation and an increase in heat production. However, until the age of 2, children remain thermolabile (body temperature rises after eating, at high ambient temperatures). In children from 3 to 10 years old, the mechanisms of thermoregulation improve, but their instability continues to persist. In prepubertal age and during puberty (puberty), when there is an increased growth of the body and a restructuring of the neurohumoral regulation of functions, the instability of thermoregulatory mechanisms increases. In old age, there is a decrease in the formation of heat in the body compared with mature age.

The temperature of individual parts of the human body is different. The lowest skin temperature is observed on the hands and feet, the highest in the armpit. In a healthy person, the temperature in this area is 36-37 ° C. During the day, there are slight rises and falls in human body temperature in accordance with the daily biorhythm: the minimum temperature is observed at 24:00 at night, the maximum at 16-19: The temperature of muscle tissue at rest and operation can fluctuate within 7 ° C. Temperature internal organs depends on the intensity of metabolic processes. The most intensive metabolic processes occur in the liver, the temperature in the liver tissues is 38 38.5 ° C. The temperature in the rectum is 3737.5 ° C. However, it can fluctuate within 45 ° C, depending on the presence of feces in it, blood supply its mucosa and other reasons.

Chemical thermoregulation. Heat exchange in the body is closely related to energy. When organic matter is oxidized, energy is released. Part of the energy goes to the synthesis of ATP. This potential energy can be used by the organism in its further activity. All tissues are the source of heat in the body. Blood, flowing through tissues, heats up. Physical thermoregulation. This process is carried out due to the transfer of heat to the external environment by convection (heat conduction), radiation (heat radiation) and water evaporation.

Convection is the direct release of heat to objects or particles of the environment adjacent to the skin. Heat transfer is more intense more difference temperature between the surface of the body and the surrounding air. Radiation - the release of heat from the body occurs by infrared radiation from the surface of the body. Due to this, the body loses the bulk of the heat.

Evaporation of water from the surface of the body occurs when sweat is released. Even in the complete absence of visible sweating, invisible sweating evaporates through the skin per day up to 0.5 liters of water. Evaporation of 1 liter of sweat in a person weighing 75 kg can lower body temperature by 10 ° C. In a state of relative rest, an adult releases 15% of heat into the external environment through heat conduction, about 66% through heat radiation and 19% due to water evaporation. On average, a person loses about 0.8 liters of sweat per day, and with it 500 kcal of heat. When breathing, a person also releases about 0.5 liters of water daily. At low ambient temperatures (15° C and below), about 90% of the daily heat transfer occurs due to heat conduction and heat radiation. At an air temperature of 1822 ° C, heat transfer due to thermal conductivity and heat radiation decreases, but heat loss by the body increases by evaporating moisture from the skin surface. Clothing that is less permeable to water vapor prevents effective sweating and can cause overheating of the human body.

Violation of thermoregulation Hyperthermia Overheating, accumulation of excess heat in the body of humans and animals with an increase in body temperature caused by external factors, hindering heat transfer to the external environment or increasing the flow of heat from the outside. Hypothermia, hypothermia is a state of the body in which the body temperature drops below what is required to maintain normal metabolism and function. In hypothermia, the body's metabolic rate decreases, resulting in a decrease in oxygen demand.

Chill-like hyperkinesis Sudden onset of chills (cold shivering), accompanied by a sensation of internal trembling, increased pilomotor reaction ("goosebumps"), internal tension; in some cases, it is combined with an increase in temperature. Chill-like hyperkinesis is often included in the picture of a vegetative crisis. Syndrome of "chilling" The syndrome of "chilling" is characterized by an almost constant feeling of "coldness in the body" or in various parts of the body - back, head. The patient complains that he is cold, goosebumps run through his body. With the “chill” syndrome, there are rather gross emotional and personality disorders (mental disorders), manifested by a senestopathic-hypochondriac syndrome with phobias. Patients do not tolerate and are afraid of drafts, sudden changes in weather, low temperatures.

"Soil Plant Nutrition" - You can also use vermiculite and perlite. Participates in the process of respiration. Potassium K. Soil nutrition of plants. It is part of the chlorophyll necessary for photosynthesis. Calcium ca. Oxidation of organic substances. Sunlight. Phosphorus P. Molybdenum Mo. Confusion. The vital activity of organisms. Water and mineral salts.

“Movement of substances in a plant” - THE SHEPHERD CUT THE BARK AT THE BIRCH” by N. Brown. root pressure. Cover fabric. The structure of the stem. Closed stoma. Sheet. So clear is the day! root zones. Vein functions. suction zone. Find out: the path of movement of water and minerals through different organs of the plant; the biological significance of the transport of substances; compliance of the structure of these plant organs with the functions performed.

"Photosynthesis and respiration of plants" - Depicted an experiment proving the need for carbon dioxide for photosynthesis. The movement of solutions of organic substances is indicated in blue. The figure shows an experiment demonstrating root pressure. Nutrition 10. All living organisms eat organic matter. What do all living organisms eat?

"Living conditions of plants" - The role of light in plant life. Plants common in dry places. An important role in the life of plants is played by the movement of air - the wind. The role of air and wind in plant life. An experiment showing the need for air for the respiration of the roots. The height of the sun above the horizon and the ratio of plants to light. Aquatic plants and plants of excessively humid places.

In total there are 17 presentations in the topic

slide 1

Thermoregulation of the body. hardening

slide 2

thermoregulation

This is the ability of animal organisms to maintain body temperature within certain limits, even if the temperature of the external environment is very different. This process is one aspect of homeostasis. If the body cannot maintain the temperature within the limits normal for this type of organism, and the temperature rises significantly above the upper limit of the norm, this condition is called hyperthermia. If the temperature drops significantly below the lower limit of normal, this condition is called hypothermia.

slide 3

Regulation is carried out by the neuro-humoral way

THERMOREGULATION = HEAT PRODUCTION HEAT DISCHARGE 1

slide 4

The role of the skin in thermoregulation

Thermal receptors 30 thousand receptors the diameter of blood vessels, skin redness, heat transfer, body temperature, sweating.

Cold receptors 250 thousand receptors the diameter of blood vessels, heat transfer, heat generation sweating.

slide 5

OVERHEATING

Overheating is a painful condition resulting from prolonged exposure to high ambient temperatures.

slide 6

HARDENING

Hardening - training and improvement of heat-regulating mechanisms, strengthening the body's ability to quickly adapt to temperature fluctuations and other changing climatic factors.

PRINCIPLES OF HARDENING: Individuality (selection of procedures under the supervision of a doctor) Graduality (gradual increase in dosage) Systematicity (repeated exposure to a factor)

Types of hardening: general (for all) special (people of a certain profession for working in extreme conditions: astronauts, divers, polar explorers)

slide 1

slide 2

Kind of activity
The dependence of body temperature on the type of activity
sleep chopping wood reading
The amount of energy released
Body temperature
Few
Many
Few
Normal
Increased
Reduced

slide 3

The role of the skin in thermoregulation of the body

slide 4

Thermoregulation is
balancing the processes of formation and release of heat in the body

slide 5

Heat generation (chemical thermoregulation)
Heat transfer (physical thermoregulation)
meal
cold shiver
muscle work
Heat conduction - the transfer of heat between bodies when they come into contact
Heat radiation - the release of heat in the form of infrared radiation
Convection - the transfer of heat from the body to the environment through the air
Evaporation of moisture from the mucous membranes in the respiratory tract

slide 6

Thermoregulatory center - hypothalamus (midbrain)

Slide 7

Plan I. Type of damage II. Symptoms III. Causes of damage IV. First aid measures

Slide 8

Sunstroke is a condition that occurs due to severe overheating of the head by direct sunlight, under the influence of which the cerebral blood vessels dilate and there is a rush of blood to the head. The first signs of sunstroke are redness of the face and severe headaches. Then there is nausea, dizziness, darkening in the eyes and vomiting. To provide first aid, the victim must be moved to a shady cool place. The patient should take a horizontal position with legs raised up. After that, you should unfasten your clothes and open the windows if help is provided in the room. The supply of fresh air is an integral part of measures to improve the condition of patients with sunstroke. To cool the skin, you can attach a piece of cloth moistened with cold water. Give the patient the optimal amount of liquid, it is better to give mineral or ordinary drinking water. When consciousness is clouded, inhalation of ammonia has a good effect. You can bring a cotton swab moistened with ammonia to the patient's nose or wipe his temples with it.

Slide 9

Violation of thermoregulation
Type of damage Symptoms Causes of damage First aid measures
Sunstroke Flushing of the face, severe headaches, nausea, dizziness, blackouts and vomiting. Overheating of the head in direct sunlight. Move to a shady cool place. Raise your legs up, unfasten your clothes and open the windows, attach a piece of cloth moistened with cold water. Bring a cotton swab moistened with ammonia and wipe the temples.

Slide 10

1. The thermoregulatory functions of the skin include: A) trembling; B) expansion and narrowing of blood vessels; B) secretion of fat; D) lifting hair on end; D) tan; E) the formation of vitamin D

slide 11

Correct answer:
A, B, G

slide 12

Choose three correct answers from six
2. When the ambient temperature drops: A) metabolism increases; B) the intensity of metabolism decreases; B) sweating increases; D) the intensity of sweating is weakened; D) skin capillaries expand; E) skin capillaries constrict

slide 13

Correct answer:
A, G, E

Slide 14

COMPARATIVE CHARACTERISTICS OF A REAL EVENT AND THE EXPERIMENT
Signs for comparison real event in the castle of the Duke of Moreau An experiment (experiment) conducted in the 19th century
What conditions were the people in? Cold room hall and stone floor 1
2 Less than a day One subject was 24 hours and the other was 8 days
What are the results of the event and experiment? 3 Changes in the health status of the subjects were not observed