Integumentary

layers of epidermis

Stratum Corneum (Top)

Stratum Granulosum

Stratum Spinosum

Stratum Basale

Stratum Corneum

the most superficial layer of the epidermis consisting of dead cells (flattened keratinocytes with no nuclei)

function: protection for epidermic, physical insults/water loss

stratum granulosum

granular layer

think layer of keratinocytes

basophilic (blue/purple)

function: keratinization

stratum spinosum

a layer of the epidermis that provides strength and flexibility to the skin

"prickly" appearance from cell-cell junctions of desmosomes

stratum basale

the deepest layer of the epidermis consisting of stem cells capable of undergoing cell division to form new cells (becomes Stratum spinosum)

cuboidal keratinocytes

basement membrane

- dense protein layer

- hemidesmosomes connect s. basal to BM

- function: physical barrier, connects epidermis -> dermis

melanocytes

Synthesize melanin

- with melanosomes + tyrosine a.a.

clear cells

melanin

A pigment that gives the skin its color

decrease in tyrosine =

loss in hair coat pugmentation

- sheep/cattle

- copper enzyme

dermis

Inner layer of skin

small amount of elastin

collagen main protein

epidermis

dermal Fibroblasts

Collagen to repair a deep skin wound is produced by __________.

dermis functions

- provides blood supply for the epidermis

- anchors epidermis in place

- focus of immune response

- Thermoregulation

dermal adnexa

- hair/feather follicles

- sebaceous gland

- apocrine gland

hair/feather follicle

a small tubular cavity containing the root of a hair

hair/feather functions

protection

sense touch

reduce heat loss

3 parts of the hair follicle

bulb (where growth starts)

root

shaft

arrector pili

tiny muscle fibers attached to the hair follicles that cause the hair to stand erect

primary hair

guard hair

secondary hair

undercoat

simple hair follicle

- where a single hair emerges from a singular orifice

sebaceous glands

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis

sebocytes

Cells that produce sebum in sebaceous glands.

rupture to release sebum

apocrine glands

Coiled structures attached to hair follicles found in the underarm and genital areas that secrete sweat.

digital pad

- ventrum of the digit

- toughest/thickest skin of body

- fibroadipose tissue

nail quick

the pink, sensitive part of the nail close to the nail bed that contains nerves and blood supply

vascular

what layer is clipped of the dog nail?

compact stratum corneum

direction of nail growth

epidermis -> nail fold

What anchors the claw to the digit?

dermis fuses with P3's periosteum

Layers of the hoof wall

1) Stratum externum

2) Stratum medium

3) Stratum internum (white line)

What hoof layer is the thickest and has the most pigment?

stratum medium

laminae in hoof

The finger-like projections of the strong tissue that attach the hoof to the bones underneath.

secondary laminae

perpendicular to primary laminae

- increase surface area & resistance to separation