Physiological functions of the skin

The surface of our human body exposed to the outside is the skin. Our skin is very strong and has a good protective effect on our body. Moreover, the surface of each person's skin is different. Some people are born with fair skin, while others are born with rough skin. The skin is composed of surface cells tightly connected together. So what are the physiological functions of the skin?

1. Protection function

The skin covers the surface of the human body, and the cells in each layer of the epidermis are tightly connected. The dermis contains a large amount of collagen fibers and elastic fibers, which make the skin both tough and soft, and have a certain tensile resistance and elasticity. When subjected to external friction or pulling, it can remain intact and return to its original shape after the external force is removed. The subcutaneous tissue is loose and contains a large number of fat cells, which acts as a cushion. The skin can block electric current. The stratum corneum of the skin is a poor conductor and has a certain insulation capacity for electric current, which can prevent a certain amount of electric current from harming the human body. The stratum corneum and melanin particles in the skin can reflect and absorb some ultraviolet rays, preventing them from entering the body and damaging internal tissues. Sebaceous glands can secrete sebum, and sweat glands can secrete sweat. The two mix to form an emulsified skin film on the skin surface, which can moisturize the stratum corneum and prevent the skin from drying out. Sweat can dilute the acidity and alkalinity of chemicals to a certain extent and protect the skin. The sebum film on the skin surface is weakly acidic, which can prevent the invasion of bacteria and fungi on the skin surface, and has antibacterial and bactericidal effects.

2. Sensory function

The skin contains many nerve endings, distributed in the epidermis, dermis and subcutaneous tissue, which make us feel "pain, touch, cold, heat, pressure, itching" and so on. Don't underestimate these sensations. When environmental changes or external stimuli have adverse effects on the body, these sensations are like the body's early warning mechanism, reminding us to take measures in time to prevent various infringements. With the help of the sensory function of the skin and in coordination with other sensory organs, humans can lead a normal life.

3. Regulate body temperature

Body temperature is a manifestation of heat generated during the metabolism of substances in the body, and is also one of the indispensable conditions for the body's cells to carry out various biochemical reactions and physiological activities. Regulating body temperature is one of the important functions of the skin. The skin is an important component of the body's heat dissipation. It can regulate body temperature through skin vasoconstriction, piloerection, reduced sweating, etc. It can also dissipate heat through physical methods such as radiation, convection, conduction, and evaporation.

4 Secretion and excretion

The eccrine glands of the skin have the function of secreting and excreting sweat. After being discharged, sweat mixes with sebum to form a milky lipid film, which can make the stratum corneum soft and moisturized and prevent it from drying out. Sweat makes the skin acidic to a certain extent, which can inhibit the growth of bacteria. The sebaceous glands can secrete sebum. When the ambient temperature rises, the viscosity of the sebum decreases and it is easier to be discharged from the hair follicles and mix with sweat to form a milky lipid film, which plays a role in protecting the skin.