Skin

Question 1

Functions of the skin (7)

Answer 1

Thermoregulation
Sensory perception
Protection
Waste excretion
Water balance
Vitamin D production
Immunity

Question 2

3 layers of the skin (top to bottom)

Answer 2

Epidermis, dermis, hypodermis

Question 3

5 layers of epidermis (bottom to top)

Answer 3

Stratum basal, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum

Question 4

Stratum basal (function)

Answer 4

Where other cells arise from
Constantly dividing
Bound to underlying CT (dermis)

Question 5

Stratum spinosum (function)

Answer 5

“Prickle cells” (spiny projections from desmosomes)

Ensures basal layer is not damaged as it is responsible for new cells

Question 6

Stratum granulosum (function)

Answer 6

Granular layer

Keratinocytes accumulate keratin as they migrate to surface

Question 7

Stratum lucidum (function)

Answer 7

Only in thick skin (soles and palms)
Lucid meaning clear
Filled with form of keratin (eleidin)
No hair

Question 8

Stratum cornuem (function)

Answer 8

Dead cells on surface full of keratin
No nuclei
Flat
Waterproof barrier
Desquamation (cells shed)

Question 9

What is keratinisation?

Answer 9

Cells flatten
Nuclei disappear
Full of keratin
Stratum corneum

Question 10

4 cells of epidermis

Answer 10

Keratinocytes
Langerhans cells
Melanocytes
Merkel cells

Question 11

Keratinocytes (function)

Answer 11

Protection

Produce keratin

Question 12

Langerhans cells (function, location and structure)

Answer 12

Antigen presenting cell
Dendritic cell
Reside in spinosum

Question 13

What does an antigen presenting cell do?

Answer 13

Ingest invading organism
Digest
Present antigens on surface of cell membrane 
APC to lymph node
Warns immune system

Question 14

Melanocytes (function, location)

Answer 14

Produce melanin (protect nuclei from UV light)
Located in basal

Question 15

How does a melanocytes protect the nuclei from UV light? What is the process of tanning called?

Answer 15

Melanocytes ingested by keratinocytes (endocytosis) and moved to apex to protect nucleus

Sun exposure = melanogenesis (tan)

Question 16

Merkel cell (function and location)

Answer 16

Mechanoreceptors
Present in highly sensitive skin
Interact with cells in different layers
Located in basal

Question 17

What are the two layers of the dermis (top to bottom)?

Answer 17

Papillary dermis, reticular dermis

Question 18

How are the dermis and epidermis connected?

Answer 18

Contact surface is corrugated with epidermal ridges and dermal papilla

Question 19

Papillary dermis (type of CT, location)

Answer 19

Thin
Just below epidermis
Loose CT

Question 20

Reticular dermis (type of CT)

Answer 20

Dense CT
Thick collagen fibres
Strength

Question 21

Hypodermis (structure and function)

Answer 21

Layer of adipose tissue
Underlines skin

Insulation, storage, cushioning

Question 22

3 skin appendages

Answer 22

Nerves, sweat glands, hair (and hair follicles)

Question 23

Nerves (different ____ for each ____)

Answer 23

Different nerve fibre for each sense (temp., touch, pain, pressure)

Question 24

Two types of sweat glands

Answer 24

Merocrine, apocrine

Question 25

Merocrine sweat glands (location)

Answer 25

Widely distributed

Question 26

Apocrine sweat glands (location)

Answer 26

Restricted, under arms

Connected to hair follicles

Question 27

Function of sweat glands (2)

Answer 27

Thermoregulation

Waste removal

Question 28

Hair and hair follicles (structure and function)

Answer 28

Touch sensation and thermoregulation

Associated with sebaceous gland (sebum) and arrector pili muscle

Question 29

What happens during vasoconstriction?

Answer 29

Cold
Blood flow to deeper regions
Contraction of pili muscles (goosebumps)

Question 30

What happens during vasodilation?

Answer 30

Hot
Blood flow toward surface
Sweat (evaporation)
Arrector pili muscles relax