Integumentary System Flashcards
integumentary system includes:
skin hair nails sensory receptors sweat, oil, and ceruminous glands dermal blood vessels
skin facts
- surface area of skin in average adult is 1.2-2.2 square meters
- 7% of body weight
- 1.5-4.0 mm thick
2 regions of skin:
Epidermis & dermis
what type of tissue is the epidermis?
stratified keratinized squamous epithelium
0.1-1.0mm thick**
is epidermis avascular or vascular?
avascular
types of cells in epidermis
keratinocytes
melanocytes
merkel cells
langerhans cells
keratinocytes
make the protein KERATIN
–waxy, waterproof
melanocytes
make the pigment melanin
- -pale or dark skin etc
- -shields the nuclei of keratinocytes from UV damage
merkel cells
surrounds the ends of sensory neurons in the epidermis
–sensitive to light and touch
langerhans cells
phagocytes–> ingest foreign substances and transports them to lymph nodules for disposal
-cells made in bone marrow and migrate to epidermis
structure of the epidermis
stratum basale (deepest layer)
stratum corneum (most superficial layer)
layers in between (from deep to superficial): stratum spinosum, stratum, granulosum, stradum lucidum
what takes place in the stradum basale (deepest layer)?
- keratinocytes undergo continuous mitosis
- daughter cells are pushed in layers toward the surface
what take place in the stradum coneum (superficial layer)?
- keratinocytes DIE by the time they reach this layer
- 25-45 days of travel from stratum basale to stradum corneum
**new epidermis each month
what is the main function of the epidermis?
- prevents loss of water and entry of water
- BARRIER to PATHOGENS
what is the main function of nails?
-allows us to pick up small objects and scratch
