Page 6 - E-Biology Sec.2 2024-2025 U1_Handy
P. 6
1- Epidermis: “several epithelial layers” Stratified squamous
a) The surface layer:
? Dead non-living cells are full of horny (Keratin)
“protects the body against the microbes” (Innate immunity)
? It arises from the migration of inner epidermal cells to
the outer surface so it is always compensated from
the beneath when it’s subjected to friction.
b) The inner layer:
? Living cells compensate the horny layer.
? Its base contains pigment cells secrete granules (Melanin)
“gives the skin color”
2- Dermis: “Connective tissues”
a) Sweat glands:
? The functional unit of excretion in skin.
? It consists of thin tube coiled around itself and reaches the skin
surface (epidermal) through “sweat pores”
? It extracts the sweat from the blood on the skin surface to decrease
the body temperature.
5
Second Term
