Skin

Question 1

Name the 3 zones of skin

Answer 1

epidermis
dermis
subcuticular/hypodermis

Question 2

What are the functions of skin?

Answer 2

environmental barrier
temperature regulation
immunological
mechanical support
neurosensory
metabolic/endocrine
glandular secretion

Question 3

What are the main features of epidermis?

Answer 3

stratified squamous cells

not vascularized

Question 4

List the layers of epidermis from most internal to external.

Answer 4

basement membrane
stratum basale
stratum spinosum
stratum granulosum
(stratum lucidum)
stratum corneum

Question 5

Describe the main characteristics of the stratum basal

Answer 5

columnar/cuboidal stem cells

migrate outwards & keratinize

Question 6

What are the main general characteristics of cells within the stratum spinosum?

Answer 6

polyhedral

connected via desmosomes

Question 7

What are the main characteristics of cells in the stratum granulosum?

Answer 7

flattened

keratohyalin & lamelar granules

Question 8

Describe the general characteristics of the stratum lucidum.

Answer 8

not everywhere
thin & translucent
no nuclear detail

Question 9

Describe the stratum corneum.

Answer 9

variable # of dead keratinized cells

Question 10

Describe the keratinization process

Answer 10

keratinocytes increase in size
synthesize granules 
nuclei disintegrate
lamellar granules release lipids to extracellular spaces
cells flatten

Question 11

What are langerhans cells? What is their main function? Where are they located?

Answer 11

antigen presenting cells
stratum spinosum
move to dermis for immune function

Question 12

Describe the basic characteristics & function of melanocytes.

Answer 12

pigmented melanosome granules
stratum basal
melanosomes migrate & are phagocytosed by adjacent keratinocytes

Question 13

Describe the main characteristics of merkel cells.

Answer 13

stratum basal
vacuolated cytoplasm on dermal side
mechanoreceptors

Question 14

How does the basement membrane function?

Answer 14

stratum basal attached to BM by hemidesmosomes

structural integrity of skin

Question 15

List some inclusions within the dermis.

Answer 15

lymphatics
blood vessels
nerves
adnexae (epidermal inclusions within dermis)
collagen bundles
inflammatory cells

Question 16

Describe the structure and inclusions of the hypodermis.

Answer 16

adiposites
anchors dermis to muscle
less collagen, more BV

Question 17

What are dermal papillae?

Answer 17

adhesion between dermis & epidermis

nourishment of epidermis

Question 18

What are the layers of the dermis?

Answer 18

papillary dermis

reticular dermis

Question 19

What are Meissner’s corpuscles?

Answer 19

mechanoreceptors in hairless skin

Question 20

List the 3 main components of hair.

Answer 20

medulla
cortex
cuticle

Question 21

Where are the hair follicles?

Answer 21

in dermis, sometimes hypodermis

Question 22

What are some hair related inclusions in the dermis?

Answer 22

inner root sheath
external root sheath
dermal papilla
hair matrix

Question 23

Describe the hair cycle

Answer 23

anagen - mitotically active follicle
catagen - follicle migrates up & becomes column of cells
telogen - resting, no growth, base @ sebaceous canal

Question 24

What is the function of a primary hair follicle?

Answer 24

produce guard hair

Question 25

What are the characteristics of secondary hair follicles?

Answer 25

closer to skin no sweat gland underhairs

Question 26

Simple hair follicles have ___.

Answer 26

one hair

Question 27

Compound hair follicles have ___.

Answer 27

multiple hairs | multiple follicles fused @ sebaceous gland

Question 28

Cat skin has what types of follicles?

Answer 28

simple & groups of compound

Question 29

Sheep have ___ hair follicles

Answer 29

simple (hair) | compound (wool)

Question 30

Equine & bovine hair follicles can be described as __.

Answer 30

single & evenly distributed

Question 31

Pigs have ____ hair follicles

Answer 31

single clustered

Question 32

What are sinus hairs?

Answer 32

whiskers surrounded by blood-filled sinus with muscle attached to sheath lots of nerve bundles associated with sheath

Question 33

Function of sinus hairs

Answer 33

perception of touch | voluntary control

Question 34

What are the 2 types of skin glands?

Answer 34

sebaceous | sweat

Question 35

Sebaceous cells look like

Answer 35

large | foamy

Question 36

Sweat gland looks like

Answer 36

simple cuboidal | "empty" cavity in middle

Question 37

Sebum functions as ___.

Answer 37

antibacterial | waterproofing

Question 38

What is the method of excretion for sebaceous glands?

Answer 38

holocrine

Question 39

What is the excretion method of sweat glands?

Answer 39

merocrine | apocrine

Question 40

Describe the structure of apocrine sweat glands.

Answer 40

coiled secretory & straight duct evenly distributed cuboidal & columnar

Question 41

Describe the excretion method and location of merocrine sweat glands

Answer 41

specialized areas (footpads/frog) open directly onto skin simple cuboidal, associated with myoepithelial

Question 42

What are Meibomian glands?

Answer 42

eyelid | with duct opening directly to eye

Question 43

What and where are Ciliary glands?

Answer 43

apocrine sweat glands | open to eyelash follicles

Question 44

Epithelium in nose?

Answer 44

thick stratified squamous deep grooves (not in cattle) no hair follicles

Question 45

Describe claws

Answer 45

continuous with epidermis hard keratin sheath soft dermis with blood supply