Introduction

I chose a fairly complex topic, as it combines many sciences, the study of which is very important in the world: biology, ecology, chemistry, etc. My topic is significant in the course of school chemistry and biology. Man is a very complex living organism, but his study seemed to me quite interesting. I believe that every person should know what it consists of.

Target: to study in more detail the chemical elements that make up a person and their interaction in the body.

To achieve this goal, the following tasks:

• 1) To study the elemental composition of living organisms;
• 2) Select the main groups of chemical elements: micro and macro elements;
• 3) Determine which chemical elements are responsible for growth, muscle function, nervous system, etc.;
• 4) Conduct laboratory experiments confirming the presence of carbon, nitrogen and iron in the human body.

Methods and techniques: analysis of scientific literature, comparative analysis, synthesis, classification and generalization of the selected material; method of observation, experiment (physical and chemical).

Chemical elements in the human body

All living organisms on Earth, including humans, are in close contact with the environment. Food and drinking water contribute to the intake of almost all chemical elements into the body. They are daily introduced into the body and excreted from it. Analyzes have shown that the amount of individual chemical elements and their ratio in a healthy body of different people are approximately the same.

Many scientists believe that not only all chemical elements are present in a living organism, but each of them performs a certain biological function. The role of about 30 chemical elements, without which the human body cannot exist normally, has been reliably established. These elements are called vital. The human body consists of 60% water, 34% organic and 6% inorganic substances.

The body of a person weighing 70 kg consists of:

Carbon-12.6 kg Chlorine-200 grams

Oxygen-45.5 kg Phosphorus-0.7 kg

Hydrogen-7 kg Sulfur-175 grams

Nitrogen-2.1 kg Iron-5 grams

Calcium-1.4 kg Fluorine-100 grams

Sodium-150 grams Silicon-3 grams

Potassium - 100 grams Iodine - 0.1 grams

Magnesium-200 grams Arsenic-0.0005 grams

4 whales of life

Carbon, oxygen, nitrogen and hydrogen are the four chemical elements that chemists call the "whales of chemistry" and which at the same time are the basic elements of life. From the molecules of these four elements, not only living proteins are built, but all nature around us and in us.

Taken alone, carbon is dead rock. Nitrogen, like oxygen, is a free gas. Nitrogen has nothing to do with it. Hydrogen combined with oxygen forms water, and together they create the universe.

In its simplest compounds, it is water on Earth, clouds in the atmosphere, and air. In more complex compounds, these are carbohydrates, salts, acids, alkalis, alcohols, sugars, fats and proteins. Getting even more complicated, they reach the highest stage of development - they create life.

Carbon - the basis of life.

All organic substances from which living organisms are built differ from inorganic substances in that they are based on the chemical element carbon. The composition of organic substances includes other elements: hydrogen, oxygen, nitrogen, sulfur and phosphorus. But they all cluster around carbon, which is the main centerpiece.

Academician Fersman called it the basis of life, because life is impossible without carbon. There is no other chemical element with such peculiar properties as carbon.

However, this does not mean at all that carbon makes up the bulk of living matter. In any organism, there is only 10% carbon, 80% water, and the remaining ten percent are other chemical elements that make up the body.

A characteristic feature of carbon in organic compounds is its limitless ability to bind various elements in various combinations into atomic groups.

The human and animal body consists of organic and inorganic substances, which is determined by the form in which they consume and assimilate liquids and food.

Organic and inorganic substances have common and different properties. Inorganic substances dissolve in water and are absorbed by plants. In plants, inorganic substances change their state and pass into organic matter. This is the same chemical element, but its bonds change after it enters the plant cell from the liquid, i.e. into the structure of plant matter. Organic substances that enter the body of humans and animals with plant food are identical to the chemical elements of living matter. Assimilated by the body from plant foods, chemical elements retain the natural properties of living matter, i.e. organic state.

A living organism can absorb substances from the air, liquids, plant and animal food. With air and water, a living organism receives mainly inorganic substances, which can be part of the cells of a living organism, if they were not removed from it in a timely manner. Inorganic substances are absent in pure rain water, in distilled water and in freshly prepared juices of berries, fruits and vegetables. When storing juices of berries, fruits and vegetables, chemical elements lose their organic state and turn into inorganic substances. Only a plant has the ability to keep chemical elements in an organic state for a long time, namely until full maturation.

inorganic compounds.

1. Water, its properties and significance for biological processes.

Water is a universal solvent. It has a high heat capacity and at the same time high thermal conductivity for liquids. These properties make water an ideal liquid for maintaining the body's thermal equilibrium.

Due to the polarity of its molecules, water acts as a structure stabilizer.

Water is a source of oxygen and hydrogen, it is the main medium where biochemical and chemical reactions take place, the most important reagent and product of biochemical reactions.

Water is characterized by complete transparency in the visible part of the spectrum, which is important for the process of photosynthesis, transpiration.

Water practically does not compress, which is very important for shaping organs, creating turgor and ensuring a certain position of organs and parts of the body in space.

Water makes it possible to carry out osmotic reactions in living cells.

Water is the main means of transporting substances in the body (blood circulation, ascending and descending currents of solutions through the plant body, etc.).

Minerals.

In the composition of living organisms, modern methods of chemical analysis have revealed 80 elements of the periodic system. According to their quantitative composition, they are divided into three main groups.

Macronutrients make up the bulk of organic and inorganic compounds, their concentration ranges from 60% to 0.001% of body weight (oxygen, hydrogen, carbon, nitrogen, sulfur, magnesium, potassium, sodium, iron, etc.).

Trace elements are predominantly heavy metal ions. Contained in organisms in an amount of 0.001% - 0.000001% (manganese, boron, copper, molybdenum, zinc, iodine, bromine).

The concentration of ultramicroelements does not exceed 0.000001%. Their physiological role in organisms has not yet been fully elucidated. This group includes uranium, radium, gold, mercury, cesium, selenium and many other rare elements.

The bulk of the tissues of living organisms that inhabit the Earth are organogenic elements: oxygen, carbon, hydrogen and nitrogen, from which organic compounds are mainly built - proteins, fats, carbohydrates.

The role and function of individual elements.

Nitrogen in autotrophic plants is the initial product of nitrogen and protein metabolism. Nitrogen atoms are part of many other non-protein, but the most important compounds: pigments (chlorophyll, hemoglobin), nucleic acids, vitamins.

Phosphorus is part of many vital compounds. Phosphorus is a constituent of AMP, ADP, ATP, nucleotides, phosphorylated saccharides, and some enzymes. Many organisms contain phosphorus in mineral form (soluble cell sap phosphates, bone tissue phosphates).

After the death of organisms, phosphorus compounds are mineralized. Thanks to root secretions, the activity of soil bacteria dissolves phosphates, which makes it possible for plant and then animal organisms to assimilate phosphorus.

Sulfur is involved in the construction of sulfur-containing amino acids (cystine, cysteine), is part of vitamin B1 and some enzymes. Sulfur and its compounds are especially important for chemosynthetic bacteria. Sulfur compounds are formed in the liver as products of disinfection of toxic substances.

Potassium is found in cells only in the form of ions. Due to potassium, the cytoplasm has certain colloidal properties; potassium activates the enzymes of protein synthesis, determines the normal rhythm of cardiac activity, participates in the generation of bioelectric potentials, in the processes of photosynthesis.

Sodium (contained in ionic form) is a significant part of the mineral substances of the blood and therefore plays an important role in the regulation of water metabolism in the body. Sodium ions contribute to the polarization of the cell membrane; the normal rhythm of cardiac activity depends on the presence in the nutrient medium in the required amount of sodium, potassium, and calcium salts.

Calcium in the ionic state is a potassium antagonist. It is part of the membrane structures, in the form of salts of pectin glues together plant cells. In plant cells, it is often found as simple, needle-shaped, or intergrown calcium oxalate crystals.

Magnesium is found in cells in a certain ratio with calcium. It is part of the chlorophyll molecule, activates energy metabolism and DNA synthesis.

Iron is an integral part of the hemoglobin molecule. It is involved in the biosynthesis of chlorophyll, therefore, with a lack of iron in the soil, plants develop chlorosis. The main role of iron is participation in the processes of respiration, photosynthesis by transferring electrons as part of oxidative enzymes - catalase, ferredoxin. A certain supply of iron in the body of animals and humans is stored in the jelly-containing protein ferritin contained in the liver and spleen.

Copper is found in animals and plants, where it plays an important role. Copper is part of some enzymes (oxidases). The value of copper for the processes of hematopoiesis, the synthesis of hemoglobin and cytochromes has been established.

Every day, 2 mg of copper enters the human body with food. In plants, copper is part of many enzymes that are involved in the dark reactions of photosynthesis and other biosynthesis. Animals suffering from copper deficiency have anemia, loss of appetite, and heart disease.

Manganese is a microelement, with an insufficient amount of which chlorosis occurs in plants. Manganese also plays an important role in the processes of nitrate reduction in plants.

Zinc is part of some enzymes that activate the breakdown of carbonic acid.

Boron affects growth processes, especially in plant organisms. In the absence of this microelement in the soil, conductive tissues, flowers and ovary die off in plants.

Recently, microelements have been widely used in crop production (pre-sowing treatment of seeds), in animal husbandry (microelement additives to feed).

Other inorganic components of the cell are most often in the form of salts dissociated into ions in solution, or in an undissolved state (phosphorus salts of bone tissue, calcareous or silicon shells of sponges, corals, diatoms, etc.).

2. Basic vital compounds: proteins, carbohydrates, fats, vitamins.

Carbohydrates (saccharides). The molecules of these substances are built from only three elements - carbon, oxygen and hydrogen. Carbons are the main source of energy for living organisms. In addition, they provide organisms with compounds that are later used to synthesize other compounds.

The most famous and common carbohydrates are mono- and disaccharides dissolved in water. They crystallize and taste sweet.

Monosaccharides (monoses) are compounds that cannot be hydrolyzed. Saccharides can polymerize to form higher molecular weight compounds - di-, tri-, and polysaccharides.

Oligosaccharides. The molecules of these compounds are built from 2 - 4 molecules of monosaccharides. These compounds can also crystallize, are readily soluble in water, are sweet in taste, and have a constant molecular weight. An example of oligosaccharides can be disaccharides sucrose, maltose, lactose, stachyose tetrasaccharide, etc.

Polysaccharides (polyoses) are water-insoluble compounds (form a colloidal solution) that do not have a sweet taste. Like the previous group of carbohydrates, they can be hydrolyzed (arabans, xylans, starch, glycogen). The main function of these compounds is binding, gluing connective tissue cells, protecting cells from adverse factors.

Lipids are a group of compounds found in all living cells and are insoluble in water. The structural units of lipid molecules can be either simple hydrocarbon chains or residues of complex cyclic molecules.

Depending on the chemical nature, lipids are divided into fats and lipoids.

Fats (triglycerides, neutral fats) are the main group of lipids. They are esters of the trihydric alcohol glycerol and fatty acids or a mixture of free fatty acids and triglycerides.

Found in living cells and free fatty acids: palmitic, stearic, ricinic.

Lipoids are fat-like substances. They are of great importance, because due to their structure they form clearly oriented molecular layers, and the ordered arrangement of hydrophilic and hydrophobic ends of molecules is of paramount importance for the formation of membrane structures with selective permeability.

Vitamins have a high physiological activity, a complex and diverse chemical structure. They are essential for normal growth and development of the body. Vitamins regulate the oxidation of carbohydrates, organic acids, amino acids, some of which are part of NAD, NADP.

The biosynthesis of vitamins is characteristic mainly of green plants. In animal organisms, only vitamins D and E are synthesized independently. Vitamins are divided into two groups: water-soluble (C, B1, B2, folic acid, B5, B12, B6, PP) and fat-soluble (A, D, E, K).

http://schools.keldysh.ru/

As you know, all substances can be divided into two large categories - mineral and organic. Many examples of inorganic or mineral substances can be cited: salt, soda, potassium. But what types of connections fall into the second category? Organic substances are present in any living organism.

Squirrels

The most important example of organic substances are proteins. They include nitrogen, hydrogen and oxygen. In addition to them, sometimes sulfur atoms can also be found in some proteins.

Proteins are among the most important organic compounds and they are the most commonly found in nature. Unlike other compounds, proteins have certain characteristic features. Their main property is a huge molecular weight. For example, the molecular weight of an alcohol atom is 46, benzene is 78, and hemoglobin is 152,000. Compared to the molecules of other substances, proteins are real giants containing thousands of atoms. Sometimes biologists call them macromolecules.

Proteins are the most complex of all organic structures. They belong to the class of polymers. If you look at a polymer molecule under a microscope, you can see that it is a chain consisting of simpler structures. They are called monomers and are repeated many times in polymers.

In addition to proteins, there are a large number of polymers - rubber, cellulose, as well as ordinary starch. Also, a lot of polymers were created by human hands - nylon, lavsan, polyethylene.

Protein formation

How are proteins formed? They are an example of organic substances whose composition in living organisms is determined by the genetic code. In their synthesis, in the overwhelming majority of cases, various combinations are used.

Also, new amino acids can be formed already when the protein begins to function in the cell. At the same time, only alpha-amino acids are found in it. The primary structure of the described substance is determined by the sequence of residues of amino acid compounds. And in most cases, the polypeptide chain, during the formation of a protein, twists into a helix, the turns of which are located closely to each other. As a result of the formation of hydrogen compounds, it has a fairly strong structure.

Fats

Fats are another example of organic matter. A person knows many types of fats: butter, beef and fish fat, vegetable oils. In large quantities, fats are formed in the seeds of plants. If a peeled sunflower seed is placed on a sheet of paper and pressed down, an oily stain will remain on the sheet.

Carbohydrates

No less important in wildlife are carbohydrates. They are found in all plant organs. Carbohydrates include sugar, starch, and fiber. They are rich in potato tubers, banana fruits. It is very easy to detect starch in potatoes. When reacted with iodine, this carbohydrate turns blue. You can verify this by dropping a little iodine on a potato slice.

Sugars are also easy to spot - they all taste sweet. Many carbohydrates of this class are found in the fruits of grapes, watermelons, melons, apple trees. They are examples of organic substances that are also produced under artificial conditions. For example, sugar is extracted from sugar cane.

How are carbohydrates formed in nature? The simplest example is the process of photosynthesis. Carbohydrates are organic substances that contain a chain of several carbon atoms. They also contain several hydroxyl groups. During photosynthesis, inorganic sugars are formed from carbon monoxide and sulfur.

Cellulose

Fiber is another example of organic matter. Most of it is found in cotton seeds, as well as plant stems and their leaves. Fiber consists of linear polymers, its molecular weight ranges from 500 thousand to 2 million.

In its pure form, it is a substance that has no smell, taste and color. It is used in the manufacture of photographic film, cellophane, explosives. In the human body, fiber is not absorbed, but it is a necessary part of the diet, as it stimulates the work of the stomach and intestines.

Substances organic and inorganic

You can give many examples of the formation of organic and second always come from minerals - inanimate which are formed in the depths of the earth. They are also part of various rocks.

Under natural conditions, inorganic substances are formed in the process of destruction of minerals or organic substances. On the other hand, organic substances are constantly formed from minerals. For example, plants absorb water with compounds dissolved in it, which subsequently move from one category to another. Living organisms use mainly organic matter for food.

Causes of Diversity

Often schoolchildren or students need to answer the question of what are the reasons for the diversity of organic substances. The main factor is that carbon atoms are interconnected using two types of bonds - simple and multiple. They can also form chains. Another reason is the variety of different chemical elements that are included in organic matter. In addition, diversity is also due to allotropy - the phenomenon of the existence of the same element in various compounds.

How are inorganic substances formed? Natural and synthetic organic substances and their examples are studied both in high school and in specialized higher educational institutions. The formation of inorganic substances is not as complex a process as the formation of proteins or carbohydrates. For example, people have been extracting soda from soda lakes since time immemorial. In 1791, the chemist Nicolas Leblanc suggested synthesizing it in the laboratory using chalk, salt, and sulfuric acid. Once upon a time, soda, which is familiar to everyone today, was a rather expensive product. To carry out the experiment, it was necessary to ignite common salt together with acid, and then ignite the resulting sulfate together with limestone and charcoal.

Another is potassium permanganate, or potassium permanganate. This substance is obtained in industrial conditions. The formation process consists in the electrolysis of a potassium hydroxide solution and a manganese anode. In this case, the anode gradually dissolves with the formation of a violet solution - this is the well-known potassium permanganate.

some chemistry

Of the 92 chemical elements currently known to science, 81 elements have been found in the human body. Among them are 4 main ones: C (carbon), H (hydrogen), O (oxygen), N (nitrogen), as well as 8 macro- and 69 microelements.

Macronutrients

Macronutrients are substances whose content exceeds 0.005% of body weight. it Ca (calcium), Cl (chlorine), F (fluorine). K (potassium), Mg (magnesium), Na (sodium), P (phosphorus) and S (sulfur). They are part of the main tissues - bones, blood, muscles. In total, the main and macronutrients make up 99% of the human body weight.

trace elements

trace elements- these are substances, the content of which does not exceed 0.005% for each individual element, and their concentration in tissues does not exceed 0.000001%. Trace elements are also very important for normal life.

A special subgroup of trace elements are ultramicroelements contained in the body in extremely small quantities, these are gold, uranium, mercury, etc.

70-80% of the human body consists of water, the rest is organic and mineral substances.

organic matter

organic matter can be formed (or synthesized artificially) from mineral. The main component of all organic substances is carbon(the study of the structure, chemical properties, methods of obtaining and practical use of various carbon compounds is the subject of organic chemistry). Carbon is the only chemical element capable of forming a huge number of different compounds (the number of these compounds exceeds 10 million!). It is present in the composition of proteins, fats and carbohydrates, which determine the nutritional value of our food; found in all animal organisms and plants.

In addition to carbon, organic compounds often contain oxygen, nitrogen, sometimes - phosphorus, sulfur and other elements, but many of these compounds have inorganic properties. There is no sharp line between organic and inorganic substances. Main signs of organic compounds possess hydrocarbons - various compounds of carbon and hydrogen and their derivatives. Molecules of any organic substances contain hydrocarbon fragments.

A special science is engaged in the study of various types of organic compounds found in living organisms, their structure and properties - biochemistry.

Depending on their structure, organic compounds are divided into simple ones - amino acids, sugars and fatty acids, more complex ones - pigments, as well as vitamins and coenzymes (non-protein components of enzymes), and the most complex ones - squirrels and nucleic acids.

The properties of organic substances are determined not only by the structure of their molecules, but also by the number and nature of their interactions with neighboring molecules, as well as by their mutual spatial arrangement. These factors are most clearly manifested in the difference in the properties of substances in different states of aggregation.

The process of transformation of substances, accompanied by a change in their composition and (or) structure, is called chemical reaction. The essence of this process is the breaking of chemical bonds in the starting substances and the formation of new bonds in the reaction products. The reaction is considered complete if the material composition of the reaction mixture no longer changes.

Reactions of organic compounds (organic reactions) obey the general laws of the course of chemical reactions. However, their course is often more complex than in the case of the interaction of inorganic compounds. Therefore, in organic chemistry, much attention is paid to the study of reaction mechanisms.

Minerals

minerals in the human body is less than organic, but they are also vital. Such substances include iron, iodine, copper, zinc, cobalt, chromium, molybdenum, nickel, vanadium, selenium, silicon, lithium and others. Despite the small need in quantitative terms, they qualitatively affect the activity and speed of all biochemical processes. Without them, normal digestion of food and the synthesis of hormones are impossible. With a deficiency of these substances in the human body, specific disorders occur, leading to characteristic diseases. Microelements are especially important for children during the period of intensive growth of bones, muscles and internal organs. With age, a person's need for minerals decreases somewhat.

The chemical composition of the cell

mineral salts

water.
good solvent

hydrophilic(from Greek. hydro- water and fileo

hydrophobic(from Greek. hydro- water and phobos

elasticity

Water. Water- universal solvent hydrophilic. 2- hydrophobic. .3- heat capacity. 4- Water is characterized 5- 6- Water provides movement of substances 7- In plants, water determines turgor support functions 8- Water is an integral part lubricating fluids slime

mineral salts. action potential ,

Physical and chemical properties of water as the main medium in the human body.

Of the inorganic substances that make up the cell, water is the most important. Its amount is from 60 to 95% of the total cell mass. Water plays an essential role in the life of cells and living organisms in general. In addition to being part of their composition, for many organisms it is also a habitat. The role of water in the cell is determined by its unique chemical and physical properties, mainly related to the small size of the molecules, the polarity of its molecules and their ability to form hydrogen bonds with each other.

Lipids. Functions of lipids in the human body.

Lipids are a large group of substances of biological origin, highly soluble in organic solvents such as methanol, acetone, chloroform and benzene. At the same time, these substances are insoluble or slightly soluble in water. Weak solubility is associated with an insufficient content of atoms with a polarizable electron shell, such as O, N, S or P, in lipid molecules.

The system of humoral regulation of physiological functions. Principles of gum..

Humoral physiological regulation uses body fluids (blood, lymph, cerebrospinal fluid, etc.) to transmit information. Signals are transmitted through chemicals: hormones, mediators, biologically active substances (BAS), electrolytes, etc.

Features of humoral regulation: does not have an exact addressee - with the current of biological fluids, substances can be delivered to any cells of the body; the speed of information delivery is low - it is determined by the flow rate of biological fluids - 0.5-5 m / s; duration of action.

The transmission of humoral regulation is carried out by the flow of blood, lymph, by diffusion, nervous - comes from nerve fibers. The humoral signal propagates more slowly (with the capillary blood flow at a speed of 0.05 mm/s) than the nerve signal (the nerve transmission speed is 130 m/s). The humoral signal does not have such an exact addressee (it works on the principle of “everyone, everyone, everyone”) as the nerve signal (for example, a nerve impulse is transmitted to the contracting muscles of the finger). But this difference is not significant, since cells have different sensitivity to chemicals. Therefore, chemicals act on strictly defined cells, that is, on those that are able to perceive this information. Cells that have this high sensitivity to any humoral factor are called target cells.
Among the humoral factors, substances with a narrow
spectrum of action, that is directed by action on a limited number of target cells (for example, oxytocin), and wider (for example, adrenaline), for which there is a significant number of target cells.
Humoral regulation is used to provide reactions that do not require high speed and accuracy of execution.
Humoral regulation, like nervous regulation, is always carried out
a closed loop of regulation, in which all elements are interconnected by channels.
As for the element of the circuit of the device that monitors (SP), it is absent in the circuit of humoral regulation as an independent structure. The function of this link is performed, as a rule, by the endocrine
cell.
Humoral substances that enter the blood or lymph diffuse into the intercellular fluid and are quickly destroyed. In this regard, their action can only extend to closely located organ cells, that is, their influence is local in nature. In contrast to local action, the distant effect of humoral substances extends to target cells at a distance.

HORMONES OF THE HYPOTHALAMUS

hormone effect

Corticoliberin - Stimulates the formation of corticotropin and lipotropin

Gonadoliberin - Stimulates the formation of lutropin and follitropin

Prolactoliberin - Promotes the release of prolactin

Prolactostatin - Inhibits the release of prolactin

Somatoliberin Stimulates the secretion of growth hormone

Somatostatin - Inhibits the secretion of growth hormone and thyrotropin

Thyroliberin - Stimulates the secretion of thyrotropin and prolactin

Melanoliberin - Stimulates the secretion of melanocyte-stimulating hormone

Melanostatin - Inhibits the secretion of melanocyte-stimulating hormone

HORMONES OF ADENOHYPOPHYSIS

STH (somatotropin, growth hormone) - Stimulates body growth, protein synthesis in cells, glucose formation and lipid breakdown

Prolactin - Regulates lactation in mammals, instinct for nursing offspring, differentiation of various tissues

TSH (thyrotropin) - Regulates the biosynthesis and secretion of thyroid hormones

Corticotropin - regulates the secretion of adrenal hormones

FSH (follitropin) and LH (luteinizing hormone) - LH regulates the synthesis of female and male sex hormones, stimulates the growth and maturation of follicles, ovulation, the formation and functioning of the corpus luteum in the ovaries FSH has a sensitizing effect on follicles and Leydig cells to the action of LH, stimulates spermatogenesis

THYROID HORMONES The secretion of thyroid hormones is controlled by two "superior" endocrine glands. The region of the brain that connects the nervous and endocrine systems together is called the hypothalamus. The hypothalamus receives information about the level of thyroid hormones and secretes substances that affect the pituitary gland. Pituitary also located in the brain in the area of ​​​​a special recess - the Turkish saddle. It secretes several dozens of hormones that are complex in structure and action, but only one of them acts on the thyroid gland - thyroid-stimulating hormone or TTG. The level of thyroid hormones in the blood and signals from the hypothalamus stimulate or inhibit the release of TSH. For example, if the amount of thyroxine in the blood is small, then both the pituitary gland and the hypothalamus will know about it. The pituitary gland will immediately release TSH, which will activate the release of hormones from the thyroid gland.

Humoral regulation is the coordination of the physiological functions of the human body through blood, lymph, and tissue fluid. Humoral regulation is carried out by biologically active substances - hormones that regulate body functions at the subcellular, cellular, tissue, organ and system levels and mediators that transmit nerve impulses. Hormones are produced by endocrine glands (endocrine), as well as external secretion glands (tissue - the walls of the stomach, intestines, and others). Hormones affect the metabolism and activity of various organs, entering them through the blood. Hormones have the following properties: High biological activity; Specificity - impact on certain organs, tissues, cells; Rapidly destroyed in tissues; The size of the molecules is small, penetration through the walls of capillaries into tissues is easy.

Adrenals - paired endocrine glands of vertebrates animals and human. The zona glomeruli produce hormones called mineralcorticoids. These include :Aldosterone (basic minecortex) Corticosterone (insignificant and relatively inactive glucocorticoid hormone). Mineralcorticoids increase reabsorption Na + and excretion of K + in the kidneys. In the beam zone, glucocorticoids, which include: Cortisol. Glucocorticoids have an important effect on almost all metabolic processes. They stimulate education glucose from fat and amino acids(gluconeogenesis), oppress inflammatory, immune and allergic reactions, reduce growth connective tissue and increase the sensitivity sense organs and excitability of the nervous system. In the mesh zone are produced sex hormones (androgens, which are precursors estrogen). These sex hormones play a slightly different role than the hormones secreted by gonads. The cells of the adrenal medulla produce catecholamines - adrenalin and norepinephrine . These hormones increase blood pressure, strengthen the work of the heart, expand the lumen of the bronchi, increase the level of sugar in the blood. At rest, they constantly release small amounts of catecholamines. Under the influence of a stressful situation, the secretion of adrenaline and noradrenaline by the cells of the adrenal medulla increases sharply.

The resting membrane potential is a deficit of positive electric charges inside the cell, which occurs due to the leakage of positive potassium ions from it and the electrogenic action of the sodium-potassium pump.

Action potential (AP). All stimuli acting on the cell cause, first of all, a decrease in PP; when it reaches a critical value (threshold), an active propagating response occurs - AP. AP amplitude approximately = 110-120 mv. A characteristic feature of AP, which distinguishes it from other forms of cell response to stimulation, is that it obeys the "all or nothing" rule, i.e., it occurs only when the stimulus reaches a certain threshold value, and a further increase in the intensity of the stimulus no longer affects amplitude, nor on the duration of the AP. The action potential is one of the most important components of the excitation process. In nerve fibers, it provides conduction of excitation from sensitive endings ( receptors) to the body of the nerve cell and from it - to the synaptic endings located on various nerve, muscle or glandular cells. Carrying out PD along the nerve and muscle fibers is carried out by the so-called. local currents, or currents of action, arising between the excited (depolarized) and neighboring resting sections of the membrane.

Post-synaptic potentials (PSPs) occur in areas of the membrane of nerve or muscle cells directly adjacent to synaptic endings. They have an amplitude of the order of several mv and duration 10-15 msec. PSPs are subdivided into excitatory (EPSP) and inhibitory (TPSP).

Generator potentials arise in the membrane of sensitive nerve endings - receptors. Their amplitude is on the order of several mv and depends on the strength of the stimulation applied to the receptor. The ionic mechanism of generator potentials has not yet been sufficiently studied.

action potential

An action potential is a rapid change in the membrane potential that occurs when nerve, muscle, and some glandular cells are excited. Its occurrence is based on changes in the ionic permeability of the membrane. There are four successive periods in the development of an action potential: local response, depolarization, repolarization, and trace potentials.

Irritability is the ability of a living organism to respond to external influences by changing its physicochemical and physiological properties. Irritability is manifested in changes in the current values ​​of physiological parameters that exceed their shifts at rest. Irritability is a universal manifestation of the vital activity of all biosystems. These environmental changes that trigger an organism's response can include a wide repertoire of responses, from diffuse protoplasmic responses in protozoa to complex, highly specialized responses in humans. In the human body, irritability is often associated with the property of nervous, muscular and glandular tissues to carry out a response in the form of generating a nerve impulse, muscle contraction or secretion of substances (saliva, hormones, etc.). In living organisms devoid of a nervous system, irritability can manifest itself in movements. So, amoebas and other protozoa leave unfavorable solutions with a high salt concentration. And plants change the position of the shoots for maximum absorption of light (stretch to the light). Irritability is a fundamental property of living systems: its presence is a classic criterion by which living things are distinguished from non-living things. The minimum value of the stimulus sufficient for the manifestation of irritability is called the threshold of perception. The phenomena of irritability in plants and animals have much in common, although their manifestations in plants differ sharply from the usual forms of motor and nervous activity of animals.

Laws of irritation of excitable tissues: 1) law of force- excitability is inversely proportional to the threshold force: the greater the threshold force, the less excitability. However, for the occurrence of excitation, only the action of the force of irritation is not enough. It is necessary that this irritation last for some time; 2) law of time stimulus action. Under the action of the same force on different tissues, different durations of irritation will be required, which depends on the ability of a given tissue to manifest its specific activity, that is, excitability: the shortest time will be required for a tissue with high excitability and the longest time - with low excitability. Thus, excitability is inversely proportional to the time of action of the stimulus: the shorter the time of action of the stimulus, the greater the excitability. The excitability of the tissue is determined not only by the strength and duration of irritation, but also by the speed (speed) of the increase in the strength of irritation, which is determined by the third law - the law of the rate of increase in the strength of stimulation(the ratio of the strength of the stimulus to the time of its action): the greater the rate of increase in the strength of irritation, the less excitability. Each tissue has its own threshold rate of increase in the strength of stimulation.

The ability of a tissue to change its specific activity in response to irritation (excitability) is inversely related to the magnitude of the threshold force, the duration of the stimulus, and the speed (rate) of the increase in the strength of the irritation.

The critical level of depolarization is the value of the membrane potential, upon reaching which an action potential arises. The critical level of depolarization (CDL) is the level of the electrical potential of the membrane of an excitable cell, from which the local potential passes into the action potential.

A local response occurs to subthreshold stimuli; extends to 1-2 mm with attenuation; increases with increasing stimulus strength, i.e. obeys the law of "force"; summed up - increases with repeated frequent pre-threshold irritations 10 - 40 mV increases.

The chemical mechanism of synaptic transmission, in comparison with the electrical one, more effectively provides the main functions of the synapse: 1) one-way signal conduction; 2) signal amplification; 3) convergence of many signals on one postsynaptic cell, plasticity of signal transmission.

Chemical synapses transmit two types of signals - excitatory and inhibitory. In excitatory synapses, a neurotransmitter released from presynaptic nerve endings causes an excitatory postsynaptic potential in the postsynaptic membrane - local depolarization, and in inhibitory synapses - an inhibitory postsynaptic potential, as a rule, hyperpolarization. The decrease in membrane resistance that occurs during an inhibitory postsynaptic potential leads to a short circuit of the excitatory postsynaptic current, thereby weakening or blocking the transmission of excitation.

The chemical composition of the cell

Organisms are made up of cells. Cells of different organisms have similar chemical composition. About 90 elements are found in the cells of living organisms, and approximately 25 of them are found in almost all cells. According to the content in the cell, chemical elements are divided into three large groups: macroelements (99%), microelements (1%), ultramicroelements (less than 0.001%).

Macroelements include oxygen, carbon, hydrogen, phosphorus, potassium, sulfur, chlorine, calcium, magnesium, sodium, iron. Microelements include manganese, copper, zinc, iodine, fluorine. Ultramicroelements include silver, gold, bromine, selenium.

The lack of any element can lead to illness, and even death of the body, since each element plays a specific role. Macronutrients of the first group form the basis of biopolymers - proteins, carbohydrates, nucleic acids, and lipids, without which life is impossible. Sulfur is part of some proteins, phosphorus is part of nucleic acids, iron is part of hemoglobin, and magnesium is part of chlorophyll. Calcium plays an important role in metabolism. Part of the chemical elements contained in the cell is part of inorganic substances - mineral salts and water.

mineral salts are in the cell, as a rule, in the form of cations (K +, Na +, Ca 2+, Mg 2+) and anions (HPO 2-/4, H 2 PO -/4, CI -, HCO 3), the ratio of which determines the acidity of the medium, which is important for the life of cells.

Of the inorganic substances in wildlife, a huge role is played by water.
It makes up a significant mass of most cells. A lot of water is contained in the cells of the brain and human embryos: more than 80% of water; in adipose tissue cells - only 40%. By old age, the water content in the cells decreases. A person who has lost 20% of water dies. The unique properties of water determine its role in the body. It is involved in thermoregulation, which is due to the high heat capacity of water - the consumption of a large amount of energy when heated. Water - good solvent. Due to the polarity, its molecules interact with positively and negatively charged ions, thereby contributing to the dissolution of the substance. In relation to water, all substances of the cell are divided into hydrophilic and hydrophobic.

hydrophilic(from Greek. hydro- water and fileo- love) are called substances that dissolve in water. These include ionic compounds (eg salts) and some non-ionic compounds (eg sugars).

hydrophobic(from Greek. hydro- water and phobos- fear) are called substances that are insoluble in water. These include, for example, lipids.

Water plays an important role in the chemical reactions that take place in the cell in aqueous solutions. It dissolves metabolic products that are unnecessary to the body and thereby contributes to their removal from the body. The high water content in the cell gives it elasticity. Water facilitates the movement of various substances within the cell or from cell to cell.

Inorganic compounds in the human body.

Water. Of the inorganic substances that make up the cell, water is the most important. Its amount is from 60 to 95% of the total cell mass. Water plays an essential role in the life of cells and living organisms in general. In addition to being part of their composition, for many organisms it is also a habitat. The role of water in a cell is determined by its unique chemical and physical properties associated mainly with the small size of its molecules, with the polarity of its molecules and with their ability to form hydrogen bonds with each other. Water as a component of biological systems performs the following essential functions: 1- Water- universal solvent for polar substances, such as salts, sugars, alcohols, acids, etc. Substances that are highly soluble in water are called hydrophilic. 2- Water does not dissolve or mix with non-polar substances, since it cannot form hydrogen bonds with them. Substances that are insoluble in water are called hydrophobic. Hydrophobic molecules or their parts are repelled by water, and in its presence are attracted to each other. Such interactions play an important role in ensuring the stability of membranes, as well as many protein molecules, nucleic acids, and a number of subcellular structures. .3- Water has a high specific heat capacity. 4- Water is characterized high heat of vaporization, That is, the ability of molecules to carry away with them a significant amount of heat while cooling the body. 5- Water is exclusively high surface tension. 6- Water provides movement of substances in the cell and the body, the absorption of substances and the excretion of metabolic products. 7- In plants, water determines turgor cells, and in some animals performs support functions being a hydrostatic skeleton (round and annelids, echinoderms). 8- Water is an integral part lubricating fluids(synovial - in the joints of vertebrates, pleural - in the pleural cavity, pericardial - in the pericardial sac) and slime(facilitate the movement of substances through the intestines, create a humid environment on the mucous membranes of the respiratory tract). It is part of saliva, bile, tears, sperm, etc.

mineral salts. In the composition of living organisms, modern methods of chemical analysis have revealed 80 elements of the periodic system. According to their quantitative composition, they are divided into three main groups. Macronutrients make up the bulk of organic and inorganic compounds, their concentration ranges from 60% to 0.001% of body weight (oxygen, hydrogen, carbon, nitrogen, sulfur, magnesium, potassium, sodium, iron, etc.). Trace elements are predominantly heavy metal ions. Contained in organisms in an amount of 0.001% - 0.000001% (manganese, boron, copper, molybdenum, zinc, iodine, bromine). The concentration of ultramicroelements does not exceed 0.000001%. Their physiological role in organisms has not yet been fully elucidated. This group includes uranium, radium, gold, mercury, cesium, selenium and many other rare elements. Essential is not only the content, but also the ratio of ions in the cell. The difference between the number of cations and anions on the surface and inside the cell provides the occurrence action potential , what underlies the emergence of nervous and muscular excitation.

The bulk of the tissues of living organisms that inhabit the Earth are organogenic elements: oxygen, carbon, hydrogen and nitrogen, from which organic compounds are mainly built - proteins, fats, carbohydrates.