Thursday, 30 April 2020
Describe the structure and function of the mammalian skin
It
has a cornified layer made up of dead cells and is tough and impermeable to
water; to protect the skin against mechanical damage; bacterial infections and
water loss; granular layer; whose cells divide to form the cornified layer;
malpighian layer; which is made up of diving cells that give rise to a new
granular layer; contains melanin; to protect skin against ultra-violet
rays/radiations; Sebaceous glands; which secrete sebum; to make the skin
supple/soft and waterproof; sebum is also antiseptic; Blood vessels; dilate
during hot weather; increasing blood flow near the skin surface; heat loss is
enhanced; constrict; in cold weather; less blood flow; minimize heat loss;
Sensory nerve endings and receptors; enable detection of external environmental
changes; Highly coiled sweat glands; secrete sweat; to control body
temperature; when hot sweat evaporates cooling the body; sweat contains
excretory products; subcutaneous fat/adipose tissue in dermis; for insulation;
hair; to regulate body temperature; in cold weather erector pili muscles
contract; hair is raised, air trapped to insulate the body; in hot weather,
erector pili muscles relax; hair lies flat reducing insulation; dense network
of blood capillaries; supply nutrients/oxygen to skin tissues; as well as
carrying away wastes and carbon (IV) oxide away from the skin tissues; adipose tissue/sub-cutaneous layer;
serves as an insulator; helping in temperature control; helps in manufacture of
vitamin D
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