Hair Cycle

Question 1

give 6 functions of hair

Answer 1

1. protect against external factors
2. thermoinsulation
3. photoprotection
4. sensory perception
5. social interactin impact (communication, camouflage, scent)
6. wound healing

Question 2

what is the hair follicle epithelium continuous with?

Answer 2

epidermis

Question 3

that determines hair thickness? shape?

Answer 3

shape determined by shape of hair follicle; thickness determined by size of hair follicle

Question 4

what are the 4 phases of the hair growth cycle?

Answer 4

1. anagen: growth phase
2. catagen: regresion phase
3. telogen: resting phase
4. exogen + anagen

Question 5

what initiates anagen? (2)

Answer 5

1. thyroid hormones
2. growth hormones

Question 6

what happens during anagen? (2)

Answer 6

1. mitotic activity increases
2. melanin production increases

Question 7

what dampens anagen? (2)

Answer 7

1. glucocorticoids
2. estrogen

Question 8

what happens during catagen? (3)

Answer 8

1. caspase (enzyme) activity increases
2. keratinocyte apoptosis increases
3. melanin production decreases

Question 9

describe the dermal papilla and mitotic activity of telogen

Answer 9

the dermal papilla is small and there is no mitotic activity

Question 10

what is exogen?

Answer 10

shedding