skin structure and function , dermatology

Question 1

what are the 3 layers of skin

Answer 1

epidermis
dermis
hypodermis

Question 2

where is the hypodermic thickest in males and females respectively

Answer 2

males- abdomen and shoulders
women - hip, thighs, buttocks
both- palms of hands

Question 3

location of hypodermis

Answer 3

lowest layer of skin

sub-cutaneous layer

Question 4

structure of hypodermis

Answer 4

mainly contains adipose tissue

loose connective tissue- fibroblasts/macrophages/fibres

Question 5

functions of hypodermis

Answer 5

provide energy store- generate heat
insulator for underlying muscle
shock absorber
connects skin to underlying muscle and bones
makes hormones e.g leptin to control eating habits

Question 6

location of dermis

Answer 6

between epidermis and hypodermis
known as the corium
epidermis +dermis= cutis

Question 7

what are the 3 layers of the dermis

Answer 7

papillary - upper
reticular-lower
dermal papillae- interdigitating

Question 8

functions of dermis

Answer 8

contains hairs and sweat glands -thermoregulation
contains sensory structures- special senses- touch
gives structure to skin and so body shape.

Question 9

location of epidermis

Answer 9

outermost layer made of epithelial cells (keratinocytes)

Question 10

structure of epidermis

Answer 10

from outermost layer

1. stratum corneum- corny/horny layer
2. stratum lucidum- transparent layer. only on palms and soles of feet
3. stratum granulosum- granular layer. stratified squamous epithelium. increased Golgi apparatus here because your making secretory proteins.
4. stratum spinousum- cuboidal epithelium arrange in 3 layers held together by desmosomes.
5. stratum basale- basale layer. tall columnar epithelial cells. contain melanocytes. constantly renew keratinocytes by cell division.

held together laterally by adherent junctions
held together basal-apical by desmosomes.
no blood vessels

Question 11

functions of epidermis

Answer 11

prevent water loss
prevent entry to bacteria and parasites
special cells that present pathogens to immune cells
synthesis of keratin
prevents underlying tissue loss due to abrasion

Question 12

what happens in psoriasis

Answer 12

transit time of keratinocyte from basal layer to stratum corneum is reduced so stratum corneum is produced in abundance as silvery scales.

Question 13

what cells are found in the epidermis other than keratinocytes

Answer 13

melanocytes

langerhans’ cells

Question 14

what are the 4 types of skin

Answer 14

hairy skin 
non hairy skin
thick skin 
thin skin 
can be considered as 2 types as hairy is thin and non hairy is thick.

Question 15

location of non hairy (thick) skin

Answer 15

palmar surface of hand
planar surface of foot
area between fingers and toes

Question 16

functions of non-hairy thick skin

Answer 16

prevent tissue loss due to abrasion
increased friction between skin and surfaces
increased sensation

Question 17

thick vs thin skin

Answer 17

thin gas hair follicles, sebaceous glands, arrector pili muscles and thick has none of these.
thin has irregular dermal papillae and thick has regular shaped ones.
thick has a stratum lucidum whereas thin doesn’t

Question 18

name some skin appendages

Answer 18

hair
arrector pilli 
sebaceous glands 
sweat glands 
nails

Question 19

what are the types of hair from foetus to adult

Answer 19

lanugo- covers the developing foetus. thin long and black
vellus- replaces lanugo. shirt thin light coloured and soft. not connected to a sebaceous gland
terminal - head axillae, external genital region. Long, wide, dark coloured and coarse. Produced by the actions of testosterone

Question 20

functions of hair

Answer 20

Thermoregulation
partial barrier to UV rays (scalp)
sexual attraction- apocrine sweat glands secrete oils (pheromones) tat attract the opposite sex. hair traps these oils and accentuates their pungency
sensation-