Functions of Skin

FUNCTIONS OF SKIN

Primary function of skin is protection of organs. However, it has many other important functions also.

FUNCTIONS OF SKIN

 

PROTECTIVE FUNCTION

Skin forms the covering of all the organs of the body and protects these organs from the following factors:

i. Bacteria and toxic substances

ii. Mechanical blow

iii. Ultraviolet rays.

i. Protection from Bacteria and Toxic Substances

Skin covers the organs of the body and protects the organs from having direct contact with external environment. Thus, it prevents the bacterial infection.

Lysozyme secreted in skin destroys the bacteria. Keratinized stratum corneum of epidermis is responsible for the protective function of skin. This layer also offers resistance against toxic chemicals like acids and alkalis.

If the skin is injured, infection occurs due to invasion of bacteria from external environment. During injury or skin infection, the keratinocytes secrete:

a. Cytokines like interleukins, α-tumor necrosis factor and γ-interferon, which play important role in inflammation, immunological reactions, tissue repair and wound healing

b. Antimicrobial peptides like β-defensins, which prevent invasion of microbes.

ii. Protection from Mechanical Blow

Skin is not tightly placed over the underlying organs or tissues. It is somewhat loose and moves over the underlying subcutaneous tissues. So, the mechanical impact of any blow to the skin is not transmitted to the underlying tissues.

iii. Protection from Ultraviolet Rays

Skin protects the body from ultraviolet rays of sunlight. Exposure to sunlight or to any other source of ultraviolet rays increases the production of melanin pigment in skin. Melanin absorbs ultraviolet rays. At the same time, the thickness of stratum corneum increases. This layer of epidermis also absorbs the ultraviolet rays.

SENSORY FUNCTION

Skin is considered as the largest sense organ in the body. It has many nerve endings, which form the specialized cutaneous receptors These receptors are stimulated by sensations of touch, pain, pressure or temperature sensation and convey these sensations to the brain via afferent nerves. At the brain level, perception of different sensations occurs.

STORAGE FUNCTION

Skin stores fat, water, chloride and sugar. It can also store blood by the dilatation of the cutaneous blood

vessels.

SYNTHETIC FUNCTION

Vitamin D3 is synthesized in skin by the action of ultraviolet rays from sunlight on cholesterol.

REGULATION OF BODY TEMPERATURE

Skin plays an important role in the regulation of body temperature. Excess heat is lost from the body

through skin by radiation, conduction, convection and evaporation. Sweat glands of the skin play an active

part in heat loss, by secreting sweat. The lipid content of sebum prevents loss of heat from the body in cold

environment.

 REGULATION OF WATER AND ELECTROLYTE BALANCE

Skin regulates water balance and electrolyte balance by excreting water and salts through sweat.

EXCRETORY FUNCTION

Skin excretes small quantities of waste materials like urea, salts and fatty substance.

ABSORPTIVE FUNCTION

Skin absorbs fat-soluble substances and some ointments.

SECRETORY FUNCTION

Skin secretes sweat through sweat glands and sebum through sebaceous glands. By secreting sweat, skin

regulates body temperature and water balance. Sebum keeps the skin smooth and moist.

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