skin: structure and function

Question 1

What is the integumentary system?

Answer 1

• it is the skin, nails and hair.
  -it is the largest and heaviest organ of the body (15% of adult body weight)
  -takes up a lot of GP time

Question 2

what are the functions of the skin?

Answer 2

they protect against:
- dehydration
-infection
-injury/abrasion
-solar radiation

-thermoregulation
-sensation
-reapir
-vitamin d production

Question 3

what are the 3 layers of skin?

Answer 3

-epidermis–> outermost layer
-dermis–> nerves and blood vessels
-hypodermis–> fat and connective tissue

Question 4

abbreviations?

Answer 4

• dem–> skin
  -epi–> on
  -hypo–> below

Question 5

facts about the epidermis layer

Answer 5

-made up of multiple layers of differentiating keratinocytes
-the thickness of the epidermis depends on where it is in the body ex- abdomen has a thin layer however the heels have a ticker layer

Question 6

describe the 4 main layers of the epidermis?

Answer 6

basal layer (innermost layer)
- first single layer, contains stem cells and attached to the dermis
- stem cells constantly participating (dividing mitotically)
-daughter cells are constantly moving up through the epidermis differentiating as they go until they are shed from the outer surface. Takes about 20-50 days

spiny layer: the keratinocytes have many desmosomes (spines) b/w the cells strong bonds holding the epidermis together.