-The skin form the external surface of the human body.At the orifices of the mouth,nose and the anal canal, the skin join the mucous membrane at the muco-cutaneous junction (3).
-Types of human skin (1):-
- Thick skin (Non-Hairy) which has thick epidermis and found only in the palms and soles as they are the most sites subjected to abrasions and trauma and thick skin shows characteristic parallel ridges and grooves which are called "Finger prints".
- Thin skin (Hairy) which has thin epidermis and covers the rest of the body.
-Histological structure of the skin :-
skin is composed of 3 layers- Epidermis
- Dermis
- Hypodermis (Subcutaneous fatty layer)
1- Epidermis:-
- It is the outer superficial epithelial layer of skin.
- It is composed of Stratified squamous keratinized epithelium.
- The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids and the thickest on the palms(0.8mm) and soles(1.4mm).
- The epidermis is ectodermal in origin.
- The epidermis is devoid of blood vessels and gets its nutrition through diffusion.