The skin is the largest organ of the body, with a total area of about 20 square feet. The skin protects us from microbes invasion.
Layer of skin
1) Epidermis:
• stratum basale(inner)
• stratum spinosum
• stratum granulosum
• stratum licidum
• stratum corneum (outermost)
2) Dermis :
The dermis is composed of three types of tissue that are present throughout - not in layers. The types of tissue are:
• collagen
• elastic tissue
• reticular fibers
Dermis also contain Hair follicle, sebaceous glang, sweat Gland, Blood vessel and Nerve.
3) Hypodermis
Specialized Epidermal Cells of skin
There are three types of specialized cells in the epidermis.
• The melanocyte produces pigment (melanin).
• The Langerhans' cell is the frontline defense of the immune system in the skin.
• The Merkel's cell's function is not clearly known.
Functions:
1) Sensation: contains a variety of nerve endings that jump to heat and cold, touch, pressure, vibration, and tissue injury.
2) Thermoregulation : eccrine(sweat) gland & dilated blood vessel helps to heat loss. while constricted vessels greatly reduce superficial blood flow and stop heat loss.
3) Reduce fluid loss by acting semi-impermeable barrier.
4) Act as Storage centre for lipids.
5) Absorption of O2, CO2, nitroge
6) Water Resistance
