FUNCTIONS OF THE SKIN ::
1.Protection : The skin protects the internal parts of body from external injuries It also imparts shape and beauty It also protects one from heat
2. Sensation : It keeps us in contact with the external environment by informing us of touch (tactile discrimination ) temperature pain pressure vibration and stereognostic sensations
3.Temperature Regulation :: It maintains the body temperature inspite of variation in weather and other conditions through the following mechanisms
A .Sweating : Sweat secretion is regulated reflexly by the centre in medulla oblongata of the brain More sweat is given off to cool the body in summer and the sweat is inhibited to preserve the body heat in winter
B.By conduction convection and radiation a large amount of heat is lost to the atmosphere
c. Vasomotor Mechanism : By dilating and constricting the superficial vessels of the skin the skin regulates the body temperature
d. Fats in the subcutis serve as a non -conducting pad to preserve heat and they aid to maintain the body temperature
e.Hair which are more in animal and less in man serve as an insulator to heat
f. Arrectores - pilorum mechanism :: In very cold weather tremors occur and hair stand on the edges Arrectore -pilorum muscle (piloerector muscle ) fibrils by contractions generate micro -calories of heat But millions of such fibrils do contribute a little heat which aids to combat cold
4.Secretions :: Sweat has been explained above sebum an oily secretion is secreted through sebacious glands This keeps the skin oily and prevents drying of the skin Cerruminous secretion in the ear is waxy and foreign bodies or insects stick up there and thus the drum of the ear is spared from injuries Milk is an active secretion of the breasts in woman during pregnancy and lactation for feeding the baby milk secreting glands are modified sebacious glands Nails and hair are the skin structures for defence and protection respectively
5.Absorption : Oily substances are absorbed through the skin
6.Storage :: Skin stores many substances such as : 1.water 2.salt specially Nacl 3.Fats and 4. Glucose etc
7.Consistency of PH :: The acidic sweat excretes out acids and thus aids to maintain the alkalinity of the blood
8.Synthesis of Vit D :: Ergosterol in the skin and subcutis is irradiated by ultraviolet rays of the sun This synthesizes ergosterol into Vit D2-calciferol
9.Gaseous Exchange :: In some animals skin is an important organ for the exchange of O2 and CO2 but in human beings the skin excretes only a negligible amount of CO2 during excretion of sweat
10.Excretion : Certain salts like NaCl and a metabolite like urea are also excreted The major excretion is that of water by the visible sweat and more so by the continuous evaporation of the invisible perspiration from all over the skin
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