The human integumentary system is the organs that form the inner and outer protective shell of his body. The largest of the human organs has a surprisingly complex structure.
Human integument system: structure and functions
The skin is the outer layer of the body that protects it from moisture loss, infection and mechanical shock. Its surface area is on average 1.7 m 2 . The skin is not just the boundary between the external and internal environment, it is a full-fledged organ. Human life and health directly depend on its proper functioning.
Skin structure
The epidermis is the very first outer layer of the skin. Consists of stratified epithelium. The cells of the inner part of the epithelium are constantly dividing and multiplying, and the outer ones are keratinized and fall away. This process is continuous, leading to a complete renewal of the stratum corneum every week. The pigment melanin from the inner layer of the epidermis determines the color of the skin.
The epidermis borders on the dermis with a thin plate - the basement membrane. The external papillary layer forms visible protrusions and grooves on the skin. There are holes in the glands, from which sweat flows along the grooves and moisturizes the skin. It is with the help of the dermis that the human integumentary system forms an individual pattern on the palms and soles of the feet, which does not repeat and does not change over time.
For elastic, supple and dense skin meets the mesh layer, consisting of bundles of elastic, collagen and muscle fibers. The roots of the hair and glands (sebaceous and sweaty) are located in this layer of skin.
The subcutaneous base is loose connective tissue with fatty deposits. Their volumes depend on many factors:
- age;
- floor;
- body features;
- heredity;
- Lifestyle;
- diet
- physical exercise.
The subcutaneous base with fatty tissue does not conduct heat well, so very thin people freeze more often than full ones.
Secret glands
Sweat, mammary and sebaceous glands are derivatives of the skin. The integumentary system can contain up to 3 million sweat glands! Under normal conditions, they produce a little more than half a liter of sweat, with increased external temperature or active physical work - up to 3. Water makes up most of the sweat (98%), the remaining 2% - ammonia, urea, salts, uric acid, etc.
Sebaceous glands are distributed over almost the entire surface of the human body, except for the sole of the feet and palms. Their concentration is especially high in the region of the face and head. The ducts remove sebum, consisting of wax, fat and hydrocarbon, directly into the hair sacs.
Nails and hair
Nails are special epidermal cells formed into a hard plate that protects the ends of the fingers and toes. They grow slowly, and the speed does not change throughout life. The uniform pink color of the nail indicates its full nutrition and blood supply. When changing color, you should reconsider your daily menu, enrich it with vitamins and minerals.
Hair covers the most vulnerable parts of the human body with keratinized fibers of the epidermis cells. Hair consists of brain, cortical substance and shell. Pigments responsible for the shade of hair are embedded in the cortical layer. The hair follicles containing the roots are immersed deep in the dermis. All hair follicles are formed in the womb. New bulbs in the process of life are not formed. The process of hair growth is wave-like. The stage of active growth is replaced by peace, and vice versa. The average growth rate of human hair is 0.1-0.3 mm per day.
The main functions of the skin and its derivatives
This is where the receptors responsible for touch and other response functions are located.
- Protection is the first and main function for which the entire human integumentary system functions. Bodies are closed from any external influence by a reliable shield. Nerve endings on the skin warn of danger. It is they who make us sharply pull our hand after touching boiling water. Mechanoreceptors are sensitive to touch, pressure and vibration. Thermoreceptors protect us from hypothermia and frostbite. Nocireceptors are responsible for pain. Adipose tissue protects internal organs from severe mechanical damage. Melanin, formed in the basal layer of the skin under the influence of ultraviolet radiation, protects the deepest skin structures.
- Thermoregulation. The optimal body temperature is maintained by the skin in many ways: sweating, constriction and expansion of blood vessels, accumulation of the fat layer, goosebumps.
- Absorption. The integumentary system has the ability to absorb moisture. Various substances in the form of molecules enter the epidermis and enter the bloodstream through the blood vessels. Thanks to this opportunity, a person actively uses creams, gels, masks, balms.
- Selection. Often the body needs to urgently get rid of unwanted substances, in this the human integumentary system helps. The secretory organs are able to remove them from the body to the surface of the epidermis along with sweat. And sebum, separated by sebaceous glands, moisturizes, lubricates the skin and hair, supports its healthy appearance.
- The production of vitamin D. It is formed when exposed to sunlight on the skin, through the blood vessels it enters the bloodstream. Vitamin D is essential for the body to maintain the normal functioning of the skeletal system. It helps calcium to be absorbed in the body in the right amounts. Strong bones are the foundation of any healthy body.
Human integument system - age features
The most noticeable age feature of a person is a change in hair color to light. This is because, with age, the hair follicle produces less melanin. The hairline on the temples is the first to whiten, gradually the gray hair spreads throughout the head, then throughout the body. No medicine, vitamins, supplements can stop the process, if it is already running.
Over time, the appearance of nails also changes dramatically. They lose their transparency and elasticity, become stiff, brittle and dull.
After 30 years, all skin structures undergo changes:
- elastic fibers are destroyed;
- there is dryness, a feeling of tightness;
- wrinkles become deeper and more noticeable;
- the skin is thinner and more irritated.
The integumentary system does not change immediately, it is a long physiological process that is irreversible. You can only temporarily suspend its external manifestations, carefully caring for your skin:
- avoid direct sunlight;
- Do not take a bath for too long;
- do not use regularly powder, tonal products;
- moisturize the epidermis with creams, tonics, lotions, masks.
And then your skin will delight for a long time with its healthy and flowering appearance.