The Structure Of Skin And Function

THE STRUCTURE OF THE SKIN

B

A C

D

E

A

Structure Pain receptor

B

Touch receptor

• •

Sensitive to stimulus of touch Help blind people to identify letters and read ‘Braille’ using their fingertips

C

Heat receptor

•

Sensitive to heat and any rise in temperature

D

Cold receptor

•

Sensitive to cold and any fall in temperature

E

Pressure receptor

• •

Sensitive to deep pressure rather than light touch Lie in the lower skin layers

• •

Function / Description Sensitive to pain Lie very close to the skin surfacent o detect the slightest pain

Functions of the Skin Te m p e r a t u r e c o n t r o l Alteration of the rates of blood flow in the skin and sweating helps maintain our skin and body temperature. The skin's blood vessels, sweat glands, body hair play a crucial role in regulating body temperature. When the body needs to cool down, the blood vessels will widen to allow more blood to circulate to the skin and let heat escape. The sweat glands are activated, producing sweat which goes to the surface of the skin through pores and hair follicles, evaporate and cool down the body. Body hair will lie flat so that warm air does not get trapped between your skin and your hairs. Body temperature is controlled in part by heat loss through the skin and by sweating.On the other hand, when you need to retain heat, the opposite happens: your blood vessels narrow, you produce less sweat and your hairs stand up on end to trap warm air around your body.

The sensory organ of touch Besides the senses of smell, taste, sight and hearing the sense of touch is one of our body's most important senses. Without it, we would not be able to feel the gentle touch of a dear person, the warmth of a hot cup of tea, or the wind blowing in our face. Through the specialized nerve endings in the skin, the body is able to perceive various sensations evoked by external agents The dermis is filled with many tiny nerve endings which give you information about the things with which your body comes in contact. They do this by carrying the information to the spinal cord, which sends messages to the brain where the feeling is registered. There are about 100 touch receptors in each of your fingertips. The most sensitive areas of your body are your hands, lips, face, neck, tongue, fingertips and feet. The least sensitive part is the middle of your back.

Elimination of wastes Small amounts of certain waste products, such as water and salt, are removed from the body by excretion through the surface of the skin. Most people eliminate nearly a kilogram of waste per day through the skin - mostly water, but also toxic waste materials, salts, and urea. This function is very important to the body, so much so that when more than 20% of the skin is damaged, like in burn victims, the resulting accumulation of toxic wastes in the body could be fatal.

Vitamin D synthesis Vitamin D, calciferol, is a fat-soluble vitamin. It is found in food, but can also be made by the body after exposure to ultraviolet rays from the sun. When ultraviolet radiation strikes the skin a cholesterol derivative is converted into vitamin D. Vitamin D is converted in the kidneys into calcitriol which acts on the intestinal cells to promote the absorption of calcium from the diet.