Skin

kali nie #BeautyMadnessWithBabyNurul nak buat sharing sikit.
erm... this one basic things dulu la ye..
heee.. sama sama kita kumpul ilmu..

Skin 

human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs.

Skin has three layers:

•  The epidermis, 

◎ the outermost layer of skin, provides a waterproof barrier and creates our skin tone. 

• The dermis, 

◎ beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. 

• The deeper subcutaneous tissue (hypodermis) 

          ◎ is made of fat and connective tissue.

Function of Skin

•  Protection: an anatomical barrier from pathogens and damage between the internal and external environment in bodily defense; Langerhans cells in the skin are part of the adaptive immune system. Perspiration contains lysozyme that break the bonds within the cell walls of bacteria.
• Sensation: contains a variety of nerve endings that react to heat and cold, touch, pressure, vibration, and tissue injury; see somatosensory system and haptics. 
• Heat regulation: the skin contains a blood supply far greater than its requirements which allows precise control of energy loss by radiation, convection and conduction. Dilated blood vessels increase perfusion and heatloss, while constricted vessels greatly reduce cutaneous blood flow and conserve heat. 
• Control of evaporation: the skin provides a relatively dry and semi-impermeable barrier to fluid loss. Loss of this function contributes to the massive fluid loss in burns.
•  Aesthetics and communication: others see our skin and can assess our mood, physical state and attractiveness. 
• Storage and synthesis: acts as a storage center for lipids and water, as well as a means of synthesis of vitamin D by action of UV on certain parts of the skin. 
• Excretion: sweat contains urea, however its concentration is 1/130th that of urine, hence excretion by sweating is at most a secondary function to temperature regulation. 
• Absorption: the cells comprising the outermost 0.25–0.40 mm of the skin are "almost exclusively supplied by external oxygen", although the "contribution to total respiration is negligible". In addition, medicine can be administered through the skin, by ointments or by means of adhesive patch, such as the nicotine patch or iontophoresis. The skin is an important site of transport in many other organisms. 
• Water resistance: The skin acts as a water-resistant barrier so essential nutrients are not washed out of the body.

Love,

Ladybie