04 - strucutre and fxn

Question 1

1-4. what are the four layers of the epidermis (from outer to intter)

Answer 1

1. stratum corneum
2. stratum granulosum
3. stratum spinosum
4. stratum basale

Question 2

which layer is anuclear cornified cells?

Answer 2

stratum corneum

Question 3

which layer has granules that contribute to formation of intercellular lipids in the stratum corneum?

Answer 3

stratum granulosum

Question 4

the layer where cell differentiation (keratinization) occurs

Answer 4

stratum spinosum

Question 5

site of cell division and production of daughter cells to upper layers of epidermis

consists of one lyaer of columnar cells and melanocytes

Answer 5

stratum basale

Question 6

(keratinocytes)

1. most numerous
2. produce what two things?

Answer 6

2. keratin (for keratinization) and lipid (for barrier layer)

(also produce cytokines -> cell signalling)

Question 7

(melanocytes)

1. basal layer of epidermis
2. produce what?

Answer 7

2. melanin pigment granules

Question 8

Langerhaans cells do what?

Answer 8

immune surveillance

Question 9

(phases of growth)

1. hair growth phase = ?
2. transition phase = ?
3. resting phase (most hair in this phase) = ?

Answer 9

1. anagen
2. catagen
3. telogen

Question 10

(types of hair follicles)

1. simple (1 har per follicle opening) - what species have this type?
2. compound (multiple hairs from one hair follicle opening) - what spceies have this type?

Answer 10

1. cattle and horses
2. dogs, cats, sheep, goats

Question 11

1. sebum is secreted by what?

2-3. what are two types of sweat glands and how are they different?

Answer 11

1. sebaceous glands
2. apocrine (empties into hair follice)
3. eccrine (empties onto skin - on footpads of dogs and cats)

Question 12

(dermis)

1. thickest part of skin
2. made up of collagen, elastic fibers, muscles, vessels, nerve

Question 13

what vitamin does the skin make

Answer 13

D Vitamin D