dermatology concepts

Question 1

water barrier of skin

Answer 1

protein crosslinking in corneum
tight junctions in lateral surface of granulosum (claudin)
lipid layer from lamellar secretions

Question 2

primary protein of tight junctions

Answer 2

claudin

Question 3

claudin deficiency affects…

Answer 3

water permeability

Question 4

when is water loss accelerated?

Answer 4

cold and dry winters

Question 5

two ways lotion works?

Answer 5

1. use lipids and cermides to penetrate corneum

2. recreate fluid phase of spinosum with aa, urea, and lipids

Question 6

can pathogens penetrate intact corneum?

Answer 6

many bacteria live on surface and invade pores and follicles

• a few bacteria can penetrate though
• fungus can invade (dermatophytes)
• some larval parasites can

Question 7

skin has natural moisturizing factor made of…

Answer 7

aa, lacic acid urea, and sugars (act as humectant)

Question 8

desquamation reactions

Answer 8

hydrolyze cell-cell bonds

Question 9

low water content in skin leads to…

Answer 9

flaky skin

• xerosis
• ichthyosis

Question 10

long term water immersion

Answer 10

theoretically skin can be immersed for weeks without changing permeability but clinically changes occur 2-10 days (ex trench foot)

Question 11

why do fingers get wrinkled in water?

Answer 11

autonomic response – NOT osmotic fluid transfer

-constriction of blood vessels–>reduced blood flow to fingers –>reduced volume

Question 12

what eliminates wrinkled finger response?

Answer 12

nerve injury!

Question 13

finger wrinkling in water is an osmotic fluid transfer: true or false?

Answer 13

false! it is an autonomic response