SKIN ::
Structure ::
Skin has multiple layers of cells which are divided into 1.Epidermis i.e. the superficial layers and 2.Dermis i.e. the deeper layers
Epidermis : This consists of the following :
1.Stratum Corneum the horny layer
2.Stratum Lucidum- the transparent layer
3.Stratum Granulosum- the granular layer and
4.Stratum Malphigian -the prickle -celled layers
Malphigian cells are large branched broad and thick Melanoblast granules of pigment are found in the deepest layers
Dermis : This layer is below the epidermis It has multiple layers and contains a large number of different structures
1.Melanophore Cells : They contain the pigment melanin
2.Vessels : There is arterial and venous capillary net work carrying blood and lymphatic vessels carrying lymph
3.Elastic Fibres : Minute fibres help to keep up texture of the skin
4.Sweat Glands :: They secrete sensible and insensible perspiration sweat excretes water and salt which aid to keep the skin moist and cool
5.Sebaceous Glands : They secrete only sebum to keep the skin oily and smooth
6.Nerve Endings : End -organs of touch temperature pain pressure vibration stereognostic sensation etc are embeded in the skin Through this we keep contact with the external environment
7.Arrectores-pilorum: These are minute fibrils attached to the hair roots which contract to raise the hair on their edges
8.Hair Roots :: They are implanted deep in the dermis Each root has its own oil supply through its oil sac
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