INTEGUMENT (Skin) - includes skin covering surface of body and specialized
derivatives of skin (nails & claws, hair, sebaceous & sweat glands, teeth; in
nonmammals - feathers and scales)
FUNCTIONS:
1) Protection of underlying tissues
2) Prevents desiccation
3) Provides insulation (hair and feathers)
4) Increases heat loss by changes in hair or feather position or by increased evaporative
water loss (sweating)
5) Reception of tactile, thermal or pain stimuli
6) Removal of excess water and salts
7) Production of vitamin D
8) Respiration in amphibians
COMPOSITION: 2 layers
1) Epidermis = upper layer, ectodermal origin; specialized epithelium - in mammals
composed of stratified squamous, can be thick or thin depending on stresses on that
area of skin, can also be keratinized or nonkeratinized
2) Dermis = below epidermis, mesodermal origin, dense irregular CT, thicker than epidermis;
sensory endings (tactile, thermal, pain) found throughout
- Tela subcutanea (fascia) = underlies dermis, areolar to adipose CT, connects skin tostructures underneath
I love the internet:
http://www.usd.edu/biol/faculty/swanson/histo/lecture13.html
------------------
>)-RadarMan-(<
age:38
A good word now is worth ten on a headstone -- Vermont Proverb
[This message has been edited by RadarMan (edited 16 October 1999).]