22 skin (integumentary system)

Question 1

General st5ructure

Answer 1

epidermis
dermis
hypodermis (subcutaneous)

Question 2

Hypodermis

Answer 2

white adipose and connective tissue

vary in thickness. thick on palms of hands

Question 3

Hypodermis function

Answer 3

shock absorber
storage
makes hormones
insulator

Question 4

hypodermis when ageing

Answer 4

causes the wrinkles, more susceptible to hypothermia

Question 5

Dermis

Answer 5

middle layer

has three layers: papillary and reticular and dermal papillae

Question 6

dermis function

Answer 6

contains hairs and sweat glands
has sensory structures
gives structures

Question 7

epidermis

Answer 7

outer most layer
4 or 5 layers depending on thickness
held together by adheren junctions
has some nerve endings
no blood vessels

Question 8

epidermis frunction

Answer 8

prevents waterloss
deters infection
synthesis of keratin
prevents tissue loss by abrasion

Question 9

epidermis layers:

Answer 9

top: stratum corneum (horny layer) dead keratinocytes
stratum lucidium: ONLY ON HANDS AND FEET
stratum granulosim: striated squamous epithelium
stratum spinosim: cuboidal epithelium. held together by desmosomes. first time you see golgis appear. keratin production here.
stratum basale: tall columnar cells. constantly renew keratinocytes. produce melanin. produce keratin filaments.

Question 10

keratin synthesis

Answer 10

from basal layer start tp differentiate to lamianr bodies the granular cells then theres a water barrier then cells start to die by apoptosis and form keratin.

Question 11

epidermis keratin transit time from basal layer

Answer 11

normal: 28-40 days
psoriasis: 2-3 days
hyperkeratosis: laid down too much keratin

Question 12

other cells in epidermis (there’s 3)

Answer 12

melaocytes: occur at intervals 1 in 8. produce melanin
langerhans cells:antigen presentation and what not
merkal cells: associated with sensory nerve endings 10% of cells in the epidermis.

Question 13

four types of skin:

Answer 13

hairy
non hairy
thick
thin

Question 14

types of hair (there’s 3)

Answer 14

lanugo: covers the developing fetus
vellus: short thin light colour not connected to sebaceous gland
terminal: head, eyebrows, genitalia, armpits. produced by action of testosterone.

Question 15

mechanoreceptors

Answer 15

number of different ones that register pain, temperature, vibrationa, touch, texture

Question 16

nails

Answer 16

made of alpha keratin

for protectionand as a tool