Integumentary System

Question 1

components

Answer 1

cutaneous membrane- skin
accessory structures

epidermis- epithelial tissue (keratinised stratified squamous)
dermis-
papillary
reticular- dense connective tissue
hypodermis- loose connective tissue

Question 2

functions

Answer 2

protection, excretion, sensation- touch, pain, pressure, temp, maintenance of body temp, production of melanin and keratin, synthesis of vit. D

Question 3

structure of epidermis

Answer 3

top down
surface- dead cells are shed
stratum corneum- dead, flat keratinocytes which lose organelles
stratum lucidim- flattened clear cells, layer only present in thick skin (dead)
stratum granulosum- grains of keratin produced, cells start apoptosis (cell death)
stratum spinosum- keratinocytes shrink and dehydrate
stratum basale- basal keratinocytes divide
basement membrane
dermis

Question 4

EGF- epidermal growth factor

Answer 4

process of division and regeneration controlled by EGF
stimulates cell division, keratin production and glandular secretion, accelerates tissue repair

Question 5

thick skin

Answer 5

renounced ridges (stratum lucidum)
fingertips, palms, soles
thickness- 0.6-5.4mm
strata- thick strata lucidum, spinsoum and corneum
ridges are present due to developed dermil papillae
hair follicles absent
sweat glands more numerous
more sensory receptors

Question 6

thin skin

Answer 6

rest of the body
0.10-0.15mm
no strata lucidum, thinner strata spinosum + corneum
ridges are absent
hair follicles present
sweat glands fewer
less sensory receptors

Question 7

melanocytes

Answer 7

secrete melanin (produced from amino acid tyrosine) - give skin pigment
melanin- brown, contributes to freckles and tan
protects us from UV + burning
increase in conc during sun exposure

Question 8

skin pigment + colouration

Answer 8

carotene- yellowish
blood- contributes to pink or blue colouration

Question 9

dermis

Answer 9

layer that is deep to the epidermis
supports epidermis- with collagen and elastin fibres
papillary layer- superficial layer- form ridges on thick skin (loose connective tissue- areolar)
reticular- deeper layer- dense connective tissue (fibrous network)
blood vessels- papillary plexus - supply epidermis
cutaneous plexus
sensory receptors- touch, pressure, pain receptors

Question 10

hypodermis

Answer 10

layer underneath dermis
loose connective tissue (areolar and adipose tissue)
fewer collagen fibres
adipose tissue may be stored here
connective tissue fibres interwoven with reticular layer of dermis- not attached to basement membrane

Question 11

cutaneous membrane

Answer 11

adipose tissue
areolar- loose connective tissue

Question 12

hair follicles and hair

Answer 12

functions- protection, insulation, sensation
in dermis- sebaceous gland (produces oil + secretes onto shaft)

Question 13

hair structure

Answer 13

medulla core- contains flexible soft keratin
cortex- dead keratinocytes layers of thick hard keratin, providing stiffness
cuticle- thin but tough

Question 14

hair growth

Answer 14

basal cells in hair matrix divide, daughter cells pushed towards surface, become increasingly keratinised
end of cycle- cells of hair matrix stop dividing, connections between hair matrix and root break down + hair falls out
new growth cycle begins, new hair produced and old hair shed

Question 15

subaceous gland

Answer 15

secrete sebum
oils produced in bottom ares, cells break down, oil is secreted onto hair shaft + to the skin
basal cells grow and break down cell membranes

Question 16

nails

Answer 16

protect end of fingers + toes, limit distortion
nail root- where growth occurds

Question 17

sweat glands

Answer 17

coiled structure in dermis, in duct which feeds onto shaft of hair
apocrine- found in armpits + pubic region, secrete thick odorous fluid

merocrine- produced all over body, secrete watery fluid + involved in thermoregualtion

Question 18

sweat function

Answer 18

skin surface cooling
secretion of waste products eg urea + lactate
protection via secretion of antibodies

Question 19

skin cancer

Answer 19

uncontrolled cell replication
78% basal cell carcinomas
2% malignant melanoma

Question 20

1st degree burn

Answer 20

affects epidermis, makes skin look pink/ red
inflammation which increases blood flow
stimulates increased growth of skin- flaking
eg sun burn

Question 21

2nd degree burn

Answer 21

involves damage to dermis
blisters/ scars may form

Question 22

3rd degree

Answer 22

extends to hypodermis
destroys sensory nerves in epidermis (so less painful)
dangerous as may disrupt fluid and electrolyte balance which protects from infection

Question 23

repair of injury

Answer 23

1- bleeding occurs, mast cells trigger inflammatory response
2-clot (scab) forms with fibrin network
phagocyte cells collect at bottom of clot, stratum basale migrates around edges
3- mesh produced by fibroblasts underlying wound, scab undermined by epidermal cells
4- epidermis complete, shallow depression, scar tissue around wound

Question 24

skin aging

Answer 24

intrinsic- reduction in cell activity, growth factors, immune sensitivity
leads to- white hair, increased infection risk

extrinsic- sunshine exposure, smoking
leads to- increased wrinkling, skin cancer risk