The human body is unique. And most people know about the structure of the human body only the information that was obtained during their school years. In this article we will tell you such information about human body, which amazes and surprises and about which you, most likely, have never heard or even suspected anything.
The human body has not yet been fully studied, but even what is already known for certain is simply amazing. And we are not talking about some supernatural possibilities, but about quite ordinary facts and figures.
So, everyone knows that the human body mainly consists of water. More precisely, by 60%. Yes, more than half of us are water - blood, lymph, intercellular fluid. With age, the percentage of water in the body decreases by 15-20% - this is one of the reasons for aging
1. A feeling of fatigue appears at loads of 35-65% of absolute capabilities.
2. The activity of the cardiovascular system is maximum at 18 hours, minimum at 3-4 hours.
3. The biological qualities of the offspring increase from the 1st to the 4th child, then decrease.
4. During normal breathing, a person inhales 500 cubic centimeters of air, when playing a wind instrument - 3500 cubic centimeters.
5. The surface of the lungs is about 100 square meters.
6. The right lung of a person holds more air than the left.
7. An adult takes approximately 23,000 breaths (and exhalations) per day.
8. The composition of blood plasma in the human body resembles the composition of the water of the prehistoric seas in which life originated.
9. In one contraction, the heart pumps 200 ml. blood.
10. Complete circulation of the blood of an adult is completed in 20-28 seconds, in a child - in 15 seconds, in a teenager - in 18 seconds. During the day, blood circulates through the body 1.5-2 thousand times.
11. There are 40 capillaries in 1 cubic millimeter of skin, 2500 capillaries in muscles, 4000 capillaries in cardiac muscle.
12. Three strength training sessions per week give the greatest effect.
13. Norm motor activity– 7-10 km (10,000-14,000 steps).
14. The strongest muscle in the human body is the tongue, not the heart. The heart is the most resilient muscle.
15. For young man norm of energy consumption is 3000 kcal. Of these, 1700 are for basic metabolism, 170 are for digestion, and 130 are for muscle work.
16. The total length of hair on the head grown by the average person during a lifetime is 725 kilometers.
17. Fingernails grow about 4 times faster than toenails.+
18. In one day, a person generates so much heat that it is enough to bring 33 liters of ice water to a boil.
9. It is estimated that a person consumes 2.5 tons of protein, 1.3 tons of fat, 17.5 tons of carbohydrates and 75 tons of water over a lifetime.
20. It is impossible to sneeze with your eyes open.
21. A person who smokes a pack of cigarettes a day drinks half a cup of tar a year.
22. Each human finger bends approximately 25 million times during a lifetime.
23. Women blink about 2 times more often than men.
24. In terms of hardness, tooth enamel can be compared to quartz. It is known that even the tip of a saber becomes dull when it hits the enamel.
25. On 1 square centimeter of skin there are 100 pain points, and in total there are about a million of them on the surface.
26. Scientifically, the navel is called “umbilicus”.
27. Man is the only representative of the animal world who is able to draw straight lines.
28. Men with blond hair grow a beard faster than men with dark hair.
29. When a person smiles, he uses 17 muscles.
30. Human DNA contains about 80,000 genes.
31. Men are classified as dwarfs if their height is less than 130 cm, and women – 120 cm.
32. The lifespan of leukocytes in the human body is 2-4 days, and erythrocytes – from 3 to 4 months.+
33. The names of the fingers of the hand in the French are: pous, index, major, anulaire, oriculaire.
34. The size of a person’s heart is equal to the size of his fist, and its weight in an adult will be 220-260 grams.
35. There are only 4 minerals in the human body: apatite, aragonite, calcite and cristobalite.
36. In one day, the human brain generates more electrical impulses than all the phones in the world combined.
37. “Snow blindness” - the effect of blinding a person from a strong direct beam.
38. Bacteria living in the human body total 2 kilograms.
39. 100 000 chemical reactions happens in a second in the human brain.
40. Babies are born without kneecaps. They are formed only at the age of 2-6 years.
41. The surface area of human lungs is approximately equal to the area of a tennis court.
42. At the moment of birth, there are already 14 billion cells in the child’s brain, and this number no longer increases, but even vice versa. After reaching the age of 25, this number decreases by 100 thousand per day. For example, in a minute spent reading the text, about 70 cells die. At the age of 40, the process of brain degradation accelerates sharply, and after the age of 50, neurons (nerve cells) dry out and the volume of the brain decreases.
43. In psychiatry, a syndrome accompanied by depersonalization, impaired perception of time and space, one’s own body and the environment, is officially called “Alice in Wonderland.”
44. The length of the human small intestine during life is 2.5 meters. After death, the muscles of the intestinal wall relax, and its length becomes 6 meters.
45. A person has about 2 million sweat glands on his body. The average adult loses 540 calories with every liter of sweat. Men produce 40% more sweat than women.
46. During the period of everything life cycle The female body reproduces 7 million eggs.
47. The human eye can distinguish 10 million different color shades.
48. About 40,000 bacteria “live” in the human mouth.
49. Papaphobia is the fear of the Pope (Roman). I'm not kidding.
50. The human spine consists of 33 or 34 vertebrae.
51. Sperm cells are the smallest in a man's body.
52. There are about 2000 taste buds on the human tongue.
53. In Mesopotamia there was a strict law for doctors. If the patient died, the doctor was executed. If the patient was blind, the doctor was also blinded.
54. There are about 300 bones in the body of a newborn, but only 206 remain in an adult.
55. In one year, a person’s heart beats 36,800,000 times.
56. Colorblindness is 10 times more common among men than among women.
57. About half of the human bones are in the feet and wrists.
58. During the Middle Ages, doctors, when in doubt about the diagnosis, diagnosed “syphilis”.
59. The total length of blood vessels in the human body is approximately 100,000 km.
60. The bone marrow of an adult, a loose mass that fills the internal cavities of some bones, weighs on average 2600 grams.
Over 70 years of life it gives 650 kg. red blood cells and a ton of white blood cells.
61. In a calm state, lying down, a person consumes 400-500 liters of oxygen per day, making 12-20 inhalations and exhalations per minute.
For comparison: the respiratory rate of a horse is 12 respiratory movements per minute, rats are 60, canaries are 108. In spring, the respiratory rate is on average one third higher than in autumn
62. The normal pulse in a calm state is 60-80 beats per minute, and in women the heart beats at 6-8 beats per minute. more often than in men. For severe physical activity the pulse can accelerate to 200 or more beats per minute.+
63. The total area of the cerebral cortex varies from 1468 to 1670 square centimeters.
64. Starting from the thirtieth year of life, 30-50 thousand nerve cells die every day in a person. The main dimensions of the brain decrease. With age, the brain not only loses weight, but also changes shape - it becomes flattened. In men, brain weight is maximum at 20-29 years old, in women - at 15-19.
65. The mass of the human brain is 1/46 of the total body mass, the mass of the elephant’s brain is only 1/560 of the body mass.
66. Even stern men shed 1-3 milliliters of tears every day. Tears are constantly produced by the lacrimal glands and moisturize the cornea of the eye, protecting it from exposure to air and dust.
67. Total weight muscle in a man is about 40% of body weight, and in a woman it is about 30%.
68. A hole with a diameter of 3-4 thousandths of a millimeter, pierced in a sheet of tin, behind which a light bulb is lit, is clearly visible to the normal eye.
69. The eye is capable of distinguishing 130-250 pure color tones and 5-10 million mixed shades.
70. Complete adaptation of the eye to darkness takes 60-80 minutes.
71. The finger is capable of feeling vibrations with an amplitude of two ten-thousandths of a millimeter.
72. The average surface area of human skin is about 2 square meters.
73. The skin contains 250 thousand cold receptors, 30 thousand heat receptors, a million pain endings, half a million touch receptors and three million sweat glands.
74. Average number of hairs on head:
for blondes - 140,000, for brunettes - 102,000
for brown-haired people - 109,000, for red-haired ones - 88,000.
Total number There are about 20 thousand hairs on the body, except the head.
75. Hair grows at a rate of 0.35-0.40 mm per day.
76. Fingernails grow at a rate of 0.086 millimeters per day, and toenails grow at a rate of 0.05 millimeters. Over the course of a year, about two grams of nails grow on the fingers.
77. There are about 25,000 cells in the inner ear that respond to sound. The range of frequencies perceived by hearing lies between 16 and 20,000 hertz. By the age of 35, the upper limit of hearing drops to 15,000 hertz.
78. The ear is most sensitive to the range of 2000-2300 hertz. The best ear for music (the ability to distinguish pitch) falls in the region of 80-600 hertz. Here our ear is able to distinguish, for example, two sounds with a frequency of 100 hertz and 100.1 hertz. In total, a person distinguishes between 3-4 thousand sounds of different heights.
79. We become aware of sound 35-175 milliseconds after it reaches the ear. It takes another 180-500 milliseconds for the ear to achieve the best sensitivity - to “tune in”.
80. The area of the olfactory zone of the nose is 5 sq. cm. There are about a million olfactory nerve endings located here.
81. When chewing food, the jaw muscles develop a force of up to 72 kilograms on the molars, and up to 20 kilograms on the incisors. Chewing bread requires an effort of 25 kg, and fried veal requires 15 kg.
82. The feeling of thirst appears with a loss of water equal to one percent of body weight. A loss of more than 5% can lead to fainting, and more than 10% can lead to death.
83. A sip of water - is it a lot or a little? Numerous measurements have shown that a man swallows an average of 21 milliliters of liquid in one gulp, and a woman swallows 14 milliliters.
84. Lucia Zarate (1864-1890) is considered the smallest woman in the world. At birth, the child's height was 17 centimeters. Lucia grew to 43 centimeters and weighed 2.2 kilograms.
85. Ventilation of the lungs (number of breaths multiplied by the volume of inhaled air) healthy person reaches 5-9 liters per minute.
86. A person can live without food for a week, but without water - only three days (during this period a person loses 10% of water, which leads to death
87. Nails on the toes grow more slowly than on the hands - due to less intense blood circulation, shoes, daily microtraumas
88. U different people different sensitivity to tastes - some do not feel sour, others salty. The fewer receptors “working”, the worse the sensitivity
89. Many women stubbornly struggle with excessive hair growth (hirsutism), but not everyone knows that this phenomenon has a reason: increased levels of male sex hormones.+
90. Blondes have the thinnest, but also the thickest hair. And the thickest and rarest are among redheads. Brown-haired and brunettes are the “golden mean”.
These are the facts about the human body. Indeed, man is a unique creature.
If you want to learn how to operate any mechanism, first of all you need to study its structure and operating principle. Let's say that you have learned to drive a car, but you don't know the engine at all. Then the slightest breakdown will put you in a difficult position. The human body is incomparably more complex and more perfect than any, even the most complex machine. Therefore, in order to learn how to manage it, you need to know how the human body works- the most complex and amazing “machine” in nature.
Cellular structure of the human body
The human body, as a rough estimate shows, consists of 35 trillion cells, each of them in turn has an extremely complex structure. The human body contains the most various cells, which differ from each other in structure and in the work they perform. Our muscle cells are elongated; they are able to contract and thus perform mechanical work, which imparts movement to our body. Blood cells - red and white blood cells - are adapted to carry oxygen in the body and to fight bacteria, etc. At the same time, all cells of animal and plant origin have a fundamentally similar structure, which allows us to consider the cell as the basic unit from which all living beings are built. Cells are the basis of organisms. In a living organism there is a continuous process of formation and renewal. At the same time, the process of destruction occurs. These two opposing processes are two sides body metabolism. The process of assimilation of substances that enter the body from the outside and the formation of living cell matter from them is called assimilation, and the process of decay of matter is dissimilation. These processes are a source of energy necessary for the functioning of the body.Functions of body cells
In the human body different kinds cells form organs and systems that perform various jobs. So, nervous system, consisting of a large number of cells, communicates the body with outside world and regulates the work of everyone internal organs. Musculoskeletal system performs the function of movement. Digestive system processes food and supplies the body with essential nutrients. Among the many organs of our body special place takes nervous system. Thanks to her people see the world, hear sounds, feel smells, temperature, pain, etc. All these sensations are perceived by the endings of the nerves embedded in your sense organs and transmitted to various parts of the cerebral cortex. This is led by . For example, you touch a hot object with your finger and immediately withdraw your hand. The painful sensation that you received was transmitted along nerve fibers to a certain part of the brain, and from there along other nerve pathways to the arms, causing them to contract. Such an involuntary withdrawal of the hand is an unconditional defensive reaction, or, unconditioned reflex. These reflexes exist in a person from the moment of his birth. Throughout life, a person acquires the so-called conditioned reflexes, which further determine his behavior, abilities and character.Types of temperaments in people
Even 2000 years ago, the famous ancient Greek doctor Hippocrates divided people into four types depending on their temperament.- Sanguines- active, cheerful and inquisitive people who adapt well to new living conditions.
- Phlegmatic people- slow, very calm people who know how to work hard and fruitfully.
- Cholerics- people with uncontrollable temperament. They are able to overcome significant difficulties, but if they fail at something, their efforts are quickly exhausted.
- Melancholic people- people with a weak type of nervous system. They are prone to doubt and are inactive.
Temperament types: 1 - Sanguine; 2 - Melancholic; 3 - Phlegmatic; 4 - Choleric In life, it is rare to meet people with expressed one of the listed types of temperament; much more often they have a number of traits mixed types. Depending on the temperament and other abilities of a person, his character is formed. And although the innate type of nervous system determines the properties of a person’s character, its systematic, purposeful activity can lead to changes in those properties that may be undesirable. To a greater extent this applies to young age, when the human body is very plastic and pliable. A person’s health, his ability to study and work, and the body’s resistance to various diseases greatly depend on the state of the nervous system. If, as a result of an incorrect daily routine, the alternation of work and rest is disrupted, then overwork of the nervous system can lead to a number of serious diseases. Human heart
The human body is designed in such a way that the nervous system controls the body's activities, A the heart is its main engine. Over 70 years of life human heart weighing about 300g. pumps through vessels around 220 million liters of blood. Humans are also related to the work of the heart. How does this wonderful engine work, the performance of which cannot be compared with any mechanism, even the most advanced one? What is it? The heart is located in chest somewhat asymmetrical: the smaller part is on the right, the larger part is on the left. Its walls consist of three muscle layers, intertwined in various directions. This structure ensures high strength of the heart muscle, allowing it to perform enormous work. Inside, the heart cavity is divided by a longitudinal septum into the right and left ventricles; The transverse septum separates the ventricles from the atria. The transverse septum has openings equipped with valves, thanks to which the blood pushed out of the ventricles is distilled in the desired direction.Human blood
Blood from the heart it spreads throughout the human body through the system of blood vessels - first through large, and then through increasingly thinner arterial tubes. Next, the blood enters the smallest vessels - capillaries, providing the cells of organs and tissues with oxygen and nutrients.
The total length of the capillaries is enormous. If you pull them into one thread, it will be enough to wrap the globe twice around the equator. From the capillaries, the blood returns through the veins to the heart. So blood circulation occurs in the human body. What is the role of blood in blood circulation? First of all, blood carries oxygen and nutrients, necessary for the functioning of the body. The liquid part of the blood makes up 60% and only 40% is made up of its cells, which can be divided according to their role in the body into three main types: red blood cells, white blood cells and platelets.
- Red blood cells, or, as they are called, red blood cells, contain a special substance - hemoglobin, which absorbs oxygen from the air and distributes it throughout the body.
- - white blood cells - play a protective role, “fighting” various microorganisms that enter the body from the outside.
- Platelets have the property of coagulating blood into a clot that prevents bleeding. Without them, the slightest bleeding could be fatal for a person.
Human lungs
Enrichment of blood with oxygen occurs in lungs, that are main organ in the human respiratory system. Atmospheric air enters the lungs through the respiratory tract system. These are the nasal passages, where the air is warmed and moistened, then there are the larynx, trachea and bronchi, which branch repeatedly into smaller and smaller branches. This is how air enters the alveoli - tiny bubbles, the walls of which are penetrated by a huge number of capillaries. It is here that oxygen from the air enters the blood through the thin walls of the alveoli and capillaries.. A person must take care to maintain health and not put his organs at risk dangerous diseases, for example such as .Digestion process
In addition to oxygen, the body needs nutrients that are formed from food products as a result digestion process. The great Russian physiologist I.P. Pavlov described this process very figuratively:The raw material entering the plant passes through a long series of institutions in which it is subjected to a certain mechanical and mainly chemical treatment, and through countless side gates is transferred to the body stores. In addition to the main line of establishments along which the raw material moves, there are a number of lateral chemical factories which prepare known reagents for the appropriate treatment of the raw material.The main ones of these “factories” are liver and pancreas. The importance of food for the human body is enormous. From food we get proteins - the basis of living matter, fats and carbohydrates, which serve us as energy material. In addition to these substances, the body needs water, mineral salts and vitamins, which are also found in foods. From the above, it becomes clear how important it is for the life of the body properly organize nutritious meals. It is known that irregular nutrition and dry food can lead to serious illnesses. Proper organization is of particular importance
Incredible facts
We don’t remember the internal organs until they bother us, although thanks to them we eat, breathe and walk.
Let's get acquainted with unusual facts that may amaze you.
Human intestine
The largest organ is the small intestine. It is four times longer than the average adult.
The normal human intestine contains about 1 kg of bacteria.
The Japanese have unique microbes in their intestines that help much better convert seaweed used in making sushi than people of other nationalities.
Human heart
The human heart creates enough pressure to force blood out over a distance 9 m. It's no wonder that you feel your heartbeat well. This blood pump moves blood throughout the body quickly and efficiently thanks to the strong contractions of the heart.
The heart begins to beat from the fourth week after conception, and will not stop until the person’s death.
A newborn baby has one cup of blood circulating. The circulatory system of an adult holds more than 4.5 liters of blood, which the heart pumps into all tissues in one minute 75 times.
Although the heart weighs on average 300 g, it pumps 2,000 liters of blood through the blood vessels every day.
The heart has its own electrical impulses, which means it works even outside the body, provided there is a sufficient supply of oxygen.
At the moment, 5% of the total amount of blood is in your heart, 20% of the blood goes to the brain and central nervous system, 22% goes to the kidneys.
Stomach acidity
Stomach acidity is so strong that it can dissolve the razor. However, you should not take this information too seriously and deliberately swallow a razor or other metal objects.
Hydrochloric acid, which is contained in the stomach, not only dissolves your dinner well, but is also able to dissolve many types of metals.
Blood vessels
It is estimated that in the human body, blood vessels stretch for 96,000 km. For a visual representation, you can compare this distance with the distance around the globe, which is 40,000 km. That is, all the blood vessels of one person can be spread out in length around the Earth more than twice.
Human blood
Blood cells are constantly dying and being replaced by new ones. Leukocytes (white blood cells) live from a few hours to several weeks, and erythrocytes (red blood cells) live from 90 to 125 days.
Circulates throughout the body in blood vessels only half blood. The other half is in reserve "blood depots". These “depots” include the liver, spleen and skin. The subcutaneous vessels contain 10%, the spleen 16% and the liver up to 20% of the total blood.
About 46% of blood is contained in “blood depots”. If there is a need to replenish blood, it is released from the “depot” into the blood vessels in order to continue the normal activity of the entire body. This happens, for example, with increased muscle work or blood loss. After replenishment occurs, some of the blood is refilled in the skin, spleen and liver.
Recently it was discovered that predisposition to different diseases depends on the blood type. Doctors confirmed the research of geneticists.
People with first blood group are predisposed to gastrointestinal diseases.
People with second Those with blood group may suffer from rheumatic diseases, allergies, bronchial asthma, diabetes, and heart disease.
People with third blood group suffers from pneumonia more often than others. They are susceptible to developing infections. Women often experience purulent mastitis, sepsis after childbirth, joint diseases and osteochondrosis.
People with fourth blood group suffer from colds, flu and other infections.
Not only predispositions associated with blood type are inherited, but also the diseases themselves. These could be intestinal infections, tonsillitis, pharyngitis or chronic tonsillitis.
Japanese researchers found that the first blood group affects even on character person.
Stomach protection
You get a new "tablecloth" for your stomach every three to four days. These mucus-like cells form on the walls of the stomach and are soon dissolved due to strong digestive acids. People who have an ulcer know how painful it can be without such a lining in the stomach.
Lung area
The area of a person's lungs is tennis court.
In order for the blood to be saturated with oxygen, the lungs consist of thousands of tiny branches of the bronchi. They, in turn, are filled with microscopic capillaries containing oxygen and carbon dioxide.
The large lung area facilitates metabolism, and you always get required amount oxygen.
woman's heart
A woman's heart beats faster than a man's. The only reason for this is that the mass of the female body is, as a rule, less than the mass of the male.
However, that's not all. Men's and women's hearts can actually work completely different especially when injured from a heart attack and other illnesses. The treatment that is suitable for a man's heart does not always help a woman's.
Walls of a female heart in the left chamber prevail in characteristics with the same male walls in elasticity and thinness. The more elastic the walls in the heart chamber, the lower the likelihood of hypertension.
Another feature of the female heart is a greater likelihood of stress and mental illness than in men.
In medical science, the reasons for the emergence of diagnostic tests are not yet clear. features cardiac diseases in women. For example, it is not known why electrocardiographic testing is less reliable in women than in men.
Doctors have long been accustomed to believing that cardiovascular diseases mainly occur in men. However, recently statistics indicate that women experience such diseases in a more severe form. The fatal outcome in such cases is 55% for women and 45% for men.
Liver functions
Scientists count more than 500 various liver functions. We are used to remembering the liver only after alcohol intoxication. But the liver is one of the hardest working and largest organs.
Here is a list of just a few of the main purposes of the liver: production of bile, decomposition of red blood cells, synthesis of protein in plasma, detoxification.
The average volume of blood passing through the liver is 1,500-2,000 l per day .
The liver is also temperature balance in the human body, which keeps the temperature within 37 °C.
In an intrauterine child at 8-10 weeks, the liver has weight half the whole fruit.
Occur regularly in the liver thousands of chemical reactions. It is called a filter or a chemical plant, since the liver cleanses our body of toxins and waste, and also produces substances necessary for life. From 18 to 20 hours, the liver most actively removes harmful substances.
Without the liver, we would get very severe poisoning even from milk or water.
It is difficult to meet a person who has a healthy liver by the age of 35-40 due to stress, the environment, poor nutrition, and various medications.
If a person expresses negativity, then the liver suffers. If we carry this negativity within us, then its cells suffer even more. Therefore, many doctors assure that you need to have self-control, not hold evil within yourself, learn to forgive and control your emotions.
Facts about the aorta
The aorta has a diameter of almost garden hose. Considering that an adult heart is almost the size of a fist, the size of the aorta is quite impressive.
In fact, the arteries must be quite large, because they are the main supplier of oxygenated blood to the rest of the organs.
Human lungs
Our left lung is smaller than our right. Nature created this so that there was a place for the heart to fit. Both lungs are similar in shape to each other.
Passes through your lungs every day 10,000 l air.
On average, an adult makes a day 23,000 inhalations and exhalations.
If you abuse alcohol, the proteins that protect the function of lung tissue will be destroyed. This process is called "alcohol lung."
A person living in a city for 60 years needs to cope with 0.1 g of metals, 200 g of harmful chemicals and 16 g of dust.
95% of people who died of lung cancer smoked 40-20 cigarettes a day.
Substances that have anticancer effects are called isothiocyanates. Eating vegetables containing isothiocyanates (broccoli, Chinese cabbage) at least once a week you reduce the risk of lung cancer by more than 30%.
The number of people suffering from bronchopulmonary diseases doubles every decade. Urban residents have a higher risk of developing such diseases than rural residents.
Human Vitality
If most of a person's internal organs are taken away, then he will survive. The human body may seem fragile, but it will live even if the stomach, spleen, 75% of the liver, 80% of the intestines, one kidney, one lung and genitals are removed.
Interesting fact! 25-year-old worker Phineas Gage was on earthworks in the USA and he had an accident. When a stick of dynamite exploded, a heavy metal rod 109 cm long and 3 cm in diameter flew out. It pierced Phineas’s cheek, knocking out a tooth, and then flew out through the skull and brain.
The surprising thing is that Gage did not die on the spot. Then he lost a tooth and an eye. Soon he fully recovered, retaining their mental abilities, the gift of speech and complete control over the body.
Facts about the adrenal glands
The adrenal glands (paired endocrine glands) change in size throughout our lives. The adrenal glands, located above the kidneys, are responsible for production of stress hormones(cortisol and adrenaline). In the seventh month, these glands are approximately the same size as the fetus's kidneys.
At birth, the adrenal glands become smaller and will continue to do so for all my life. When a person reaches old age, the glands are so small that they can hardly be seen.
Both adrenal glands consist of a medulla and a cortex.
They regulate the concentration of several substances in the blood and metabolic processes.
Adrenaline, which is secreted by the adrenal glands, signals danger to the human body. This causes your breathing to speed up, your blood flow to increase, and your heart to beat faster. Adrenaline is released into the blood in order to prepare for danger or run away from it.
Every educated person should know what does the human body consist of. At least in general outline. After all, everyone has their own appeal, since this is information about us.
Human tissue
Cells that are identical in structure and function form tissues. There are four types of tissues in our body.
Epithelial tissue
Epithelial tissue (integumentary tissue) forms the skin and mucous membranes of internal organs.
Its main function is to protect the body and individual organs from external influences and actively participate in the metabolic process.
Epithelial tissue cells in the intestines, for example, absorb nutrients.
Connective tissue
Connective tissue consists of blood, lymph, bones and fat. Some cells of this type of tissue carry nutrients throughout our body, others (osteocytes) serve as support for the body, and others form the basis of the human defense system.
Muscle
Name muscle tissue speaks for itself. The word “muscle” comes from the Latin “musculis”, which in turn comes from the word “mus”, which means mouse.
And indeed, when contracting, our muscles seem to run under the skin. Long cells (up to 12 cm) contain the thinnest filaments that can contract - these are myofibrils and myofilaments.
Nervous tissue
Nervous tissue consists of very special cells called neurons.
They contain a body, where the nucleus is located, and processes (axons and dendrites). The length of the axon, a long process, can reach 1.5 meters.
A weak electrical discharge passes through it from cell to cell. It's called a nerve impulse.
Did you know that the smallest cell in the human body is the red blood cell? Its diameter is about 7 microns (1 micrometer is 0.0001 centimeters).
And the largest cell is the egg. Its diameter is about 0.1 mm. It can be seen even with the naked eye.
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