intro to derm 2

Question 1

What are the 6 functions of hair

Answer 1

• thermoregulation
• protection against external factors
• apocrine sweat production
• produces sebum (oily substance on skin )
• epithelial and melanocyte stem cells
• social and sexual interaction

Question 2

What is sebum

Answer 2

oily substance on skin

Question 3

What is apocrine sweat and where is it found

Answer 3

body odour hair

in armpits and genital regions

Question 4

What are the 2 types of hair and where are they found

Answer 4

terminal hair - scalp, eyebrows and eyelashes

vallus hair - rest of body (except lips, palm and external genitalia)

Question 5

What are the 3 phases of hair development

Answer 5

anagen phase
catagen phase
telogen phase

Question 6

Describe the life cycle of a hair, describing the 3 phases and how long they last and how much hair is in each stage

Answer 6

1) anagen phase (‘and’ = growth) -where new hair forms and grows
85% of hair, lasts 2 to 6 years
2) catagen phase (‘cut’) -regressing phase
1% of hair (lasts 3 weeks)
3) telogen phase - resting phase
lasts 3 months

Question 7

Where does the sebaceous gland open into

Answer 7

hair canal

Question 8

What is the difference between the sebacious gland and the eccrine sweat gland

Answer 8

eccrine sweat gland opens up directly into the epidermis of the skin, whereas the sebacious gland opens into the hair canal

Question 9

What type of modified gland is an apocrine sweat gland

Answer 9

modified from a sebacious gland

Question 10

What lifts up the sweat gland and from where does it originate and attach to

Answer 10

erector pili

originates from top layer of dermis and attaches to the hair canal

Question 11

What is the infundibulum

Answer 11

extends from the opening of the sebacious gland to the superficial layer of the epidermis

Question 12

Where is the isthmus

Answer 12

between insertion of the erector pili and opening of the sebacious gland

Question 13

Describe where the bulb is

Answer 13

Outer root sheeth located at position of arrector pili muscle

Question 14

What type of cell is at the bulge

Answer 14

Hair follicle stem cell

Question 15

What is the function of the bulge

Answer 15

they can migrate

Question 16

Where can the cells in the bulb migrate to

Answer 16

downwards - enter bulb matrix and undergoes terminal differentiation to form hair shaft and inner root sheath
upwards - forms sebacious glands in response to wounding

Question 17

What cells reside in the bulge

Answer 17

hair follicle stem cells

Question 18

Where can the cells in the bulb migrate to

Answer 18

downwards - enter bulb matrix and undergoes terminal differentiation to form hair shaft and inner root sheath

Question 19

What is the bulb

Answer 19

lower most portion of the hair follicle - includes follicular dermal papilla and hair matrix

Question 20

Describe where the outer root sheet is

Answer 20

grows from the bulb up to the epidermis