Describe the structure and function of the mammalian skin - KCSE Biology Essays

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;