general skin appendages

Question 1

classification of hair

Answer 1

lanugo
- fine foetal hairs shed after a month

vellus
-fine unmedulated hairs replacing the lanugo hairs after a month

terminal
- long course medullated hairs on scalp or pubic hairs influencedby androgens

Question 2

what are the stages of the hair cycle

Answer 2

anagen
telogen
catagen
exogen

Question 3

what occurs in anagen

Answer 3

(Growing Phase)

The growing phase lasts two to seven years and determines the length of our hair.

Question 4

what occurs in telogen

Answer 4

Telogen (Resting Phase)

The resting phase lasts around three months. Around 10-15% of hairs are in this phase. Whilst the old hair is resting, a new hair begins the growth phase.

Question 5

what occurs in catagen

Answer 5

(Regression Phase)

This stage lasts about ten days. The hair follicle shrinks and detaches from the dermal papilla.

Question 6

what occurs in exogen

Answer 6

(Shedding Phase)

The Exogen represents the period from when a resting hair reaches its terminal position in the follicle to when it finally detaches. The resting hair is gradually loosened resulting in shedding of the hair.

Question 7

hair pathologies

Answer 7

a) reduced or absent melanin pigment production e.g. grey or white hair
b) changes in duration of the growth cycle e.g. hair loss (premature entry of hair follicles into the telogen phase)
c) shaft abnormalities

Question 8

where is the keratin of te nail formed

Answer 8

inn the nail maitrix

Question 9

location of nail matrix

Answer 9

proximal nail fold to lunule

Question 10

function of cuticle

Answer 10

seals the potential space of nail fold preventing infection

Question 11

functions of the nails

Answer 11

strength and protection of distal phalanx

fine touch and small object handling

Question 12

nail growth rate

Answer 12

0.5 - 1.2 mm week

Question 13

factors affecting nail growth

Answer 13

age= slow and brown
temp= faster in summer

Question 14

what are sebaceous glands

Answer 14

exocrine glands in the skin that secrete an oily or waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals.

Question 15

structure of sebaceous glands

Answer 15

multilobed
contain lipid
holocrine type (shed hole) 
can be free sebacous or develop from hair germs
stim by androgens

Question 16

location of free sebaceous glands

Answer 16

eyelid
mucous membranes (fordyce)
nipple
perianal
genitalia

Question 17

androgen mpst responsible for sebaceous gland stim

Answer 17

dihidryotestosterone

Question 18

how are sebaceous glands linked to acne

Answer 18

sebacoues glands respond to maternal androgens at birth ten lie dormant until ez convert weak androgens to dihidryotestosterone

Question 19

types of sweat glands

Answer 19

eccrine 
- everywhere
apocrine
-axillae, areollae, genitalia, anus
modified glands 
-external auditory canal from puberty

Question 20

eccrine anatomy

Answer 20

coiled glands

lie deep in dermis

Question 21

sweat ph

Answer 21

4.0-6.8

Question 22

what does sweat contain

Answer 22

NaCl
Kcl
lactate
urea
ammonia

Question 23

what condition increases Na in sweat

Answer 23

CF

Question 24

func of sweat

Answer 24

temp control by evap

Question 25

sweat stim

3

Answer 25

thermal
-reflex to hot environment 
-chest, back, forehead, axillae
emotional
-fear/anxiety
-palms, soles, axillae 
gustatory 
-spicy food
-face