All multicellular organisms have a skin composed of one or more layers. Main functions of the skin are …
1) Protection of the inner layers of the body from physical and chemical effects
) Prevention of the entry of the microbes !) Prevention of "ater loss in terrestrial organisms #) Protection of the cells from $% light or intense
light ) 'egulation of body temperature
 
 
1) Protection of the inner layers of the body from physical and chemical effects
Acid burn
 
 
/0
0
  hhhh!
 
 
3ormal 4air 5ollicle
 
 
1) +pidermis
 
  he keratini7ed layer is the superficial layer of dead s8uamous cells.
9t is composed of keratini7ed epithelial cells .
 
 
 
 
 
 
Pigment melanin: "hich gives the color of the skin: is present in melanocytes   of the epidermis.
melanocytes
 
 
9t is appro imately ( times thicker  than the epidermis. 9t originates from the mesoderm  in the embryo.
he dermis contains …
1)  ;lood vessels
 
 
 
 
 
 
 
 
 
 
 
 
he color of the hair is given by the pigment melanin. he more the melanin production is the blacker the
 
 
 
 
 
 
 
 
 
 
,) 1he receptors   of the skin are present in the dermis. hese receptors are functional in the reception of touch: pressure: temperature and pain. ;est kno"n receptors are …
a) Pacinian corpuscles
d) 4air follicle receptors
e) 5ree nerve endings.
 
 
 
 
a) Pacinian corpuscles   are the most important receptors of the skin.
hey are the greatest mechanoreceptors  in the skin.
 
 
b)   Meissner and Merkel?s   corpuscles  are involved in light pressure changes  and therefore located in the fingers and lips.
Meissner s corpuscle
 
 
c)   @rause and 'uffini corpuscles   are the receptors that are responsible to detect temperature changes. @rause corpuscles are for cold reception  and 'uffini corpuscles are for hot reception .
'uffini /orpuscle@rause /orpuscle