Physiology of the Skin

Question 1

4 layers of the epidermis

Answer 1

Stratum basale
S spinosum
S granulosum
S corneum

Question 2

2 layers in the diffusion barrier of the skin

Answer 2

Protein rich corneocytes

Lipid rich intercellular material

Question 3

Odland bodies or lamellar bodies

Answer 3

Produce the intercellular cement that goes between corneocytes

Question 4

2 barriers to UV radiation

Answer 4

Protein barrier (stratum corneum)
Melanin barrier

Question 5

Does UVA or UVB penetrate more deeply?

Answer 5

UVA

Question 6

4 pigments involved in skin colour

Answer 6

Brown
Red
Blue
Yellow

Question 7

3 functions of melanin

Answer 7

Protection against UV radiation
Scavenging or cytotoxic radicals
Participating in neurologic development

Question 8

Melanosomes

Answer 8

Synthesized by the melanocyte
Transported along the dendrites or cell processes
Contain melanin

Question 9

One melanocyte feeds melanin to how many keratinocytes?

Answer 9

~36

Question 10

What determines skin colour?

Answer 10

The number of melanosomes, the size of them, and the amount of melanin in them/its degradation
NOT the number of melanocytes! We all have the same number

Question 11

2 components of tanning

1. Immediate
2. Delayed

Answer 11

1. During UV exposure, redistribution of melanosomes - UVA
2. 3-4 days after UV exposure, related to increased melanocytes/dendricity/melanosomes in an SOS response to DNA damage - UVB

Question 12

3 things that cause blotches of dark in the skin

Answer 12

Light
Inflammation
Chemicals/hormones

Question 13

UV radiation needed for what hormone

Answer 13

Vitamin D3

Question 14

3 ways to increase heat loss

Answer 14

Vasodilatation
Sweating
Decrease in thermogenesis

Question 15

3 ways to conserve heat

Answer 15

Skin vasoconstriction
Piloerection
Shivering/chemical thermogenesis/thyroxine secretion