int system

Question 1

Epi Dermis

Answer 1

outer layer of skin-consists of 5 layers is epithelial tissue, is avasucular, has keratinocytes. has 5 layers.

Question 2

Clever Lucy Got Some Books

Answer 2

stratum Corneum, stratum lucidium, strata granulosum, statam spinosum, stratum basale

Question 3

stratum spinosum

Answer 3

prickle cell layer, cells have projections on outer surface to encourage close cellular structure, minimal cell division.

Question 4

statum basale

Answer 4

healthy cells here as recieve nourishment from blood in dermis below. Melancytes found here which produce melanin.
-constant cell reprod (mitosis) occurs here, this means old cells are constantly being pushed to surface where they eventually flake off.

Question 5

stratum corneum

Answer 5

75% of epidermal thickness. cells overlap like roof tiles and old ones flake off.
-made of keratin (protective dead cells) this protects deeper layers from external environment and water loss

Question 6

stratum lucidium

Answer 6

a thin layer of cells that is only present on thick and hairless skin such as heels, is used to assist water movement through skin.

Question 7

stratum granulosm

Answer 7

is the stage were living cells become keratinised (dead). they loose there organelles and become flattened
-varies in thickness

Question 8

appendage- sweat gland

Answer 8

merocrine-most common
-opens into skins surface via a duct
-primary function to cool body as sweat has a high water content
apocrine-duct empties into hair follicles
-only in genital and underarm area
-most active in puperty
-decomposes which causes body odour

Question 9

appendage-sebaceous gland

Answer 9

mostly connected to hair folicles- secrete oily substance called sebum- acts as a lubricant ad antibacterail layer on skin

Question 10

arrector pili muscle

Answer 10

involuntary smooth muscle attached to hair follicle and epidermis

• contracts in response to cold and touch
• causes goosebumps

Question 11

hypo dermis

Answer 11

anchors skin to underlying layers

• adipose tissue cushions and insulates
• contains nerve endings, sense pressure, high vibration

Question 12

dermis

Answer 12

underneath epidermis

varies in thickness 2 layers papillary, reticular

Question 13

reticular

Answer 13

80% of dermal thickness
-contains sweat, sebaceous glands, hair follicles, blood vessels, nerves, collagen and elastin
collagen gives strength to skin, elastin fibres allow skin to stretch and recoil

Question 14

papillary

Answer 14

has uneven surface which intertwines with basale layer

-made of dermal papillae

Question 15

Functions of the skin

Answer 15

S- sensation, receptors in dermis, vibration, texture, pressure, heat
H-heat regulation, is regulated by blood vessels in dermis, vasoconstriction, vasodilation
A-absorption
P-protection/immunity, nerve receptors stop you from hurting yourself, skin protects internal environment from outside, melanin protects from UV.
E- excretion excess waste, water, salts, urea
S- synthesthis of vit D