integument 3

palpebrae

eyelids, paired skin folds designed to protect the eyes

meibomian glands

specialized sebaceous glands that are in eyelids

meibum

oily substance produced by the meibomian glands

tarsal glands

aka meibomian glands, tarsal dense CT surrounds it

hair

keratinized, flexible structure produced by a hair follicle

shaft

portion that protrudes from the surface of the epidermis

root

portion within the follicle

hair bulb

terminal hollow knob/bulb

cuticle

outermost single layer of overlapping (shingle-like) keratinized cells

cortex

densely packed keratinized cells containing pigment granules

medulla

center of the hair, loosely arranged cuboidal/flattened cells, solid in the root portion

hair follicle

formed by downgrowth/invagination of the ectoderm/epidermis into the underlying mesoderm/dermis

internal epithelial root sheath

innermost layer next to the hair root

internal epithelial root sheath corresponds with

the stratum corneum of the hair follicle epithelium

external epithelial root sheath corresponds with

the strata basale and spinosum of the hair follicle epithelium

glassy membrane

basement membrane of the follicle epithelium

dermal root sheath & dermal papilla

CT enclosure of the follicle

dermal root sheath & dermal papilla is

continuous w/the dermal papilla that projects into the base of the hair bulb

dermal root sheath & dermal papilla has

collagen, elastic fibers, blood vessels, and nerves

hair matrix

dividing cells overlying the dermal papilla

hair matrix produces

a hard keratin product (the hair)

Hard keratin does not

slough individual squames like skin

pigmentation

derived from melanocytes located w/in the hair matrix

arrector pili muscle

smooth muscle, innervated by ANS

arrector pili muscle spans

btwn the dermal root sheath of the follicle & the papillary layer of the dermis

arrector pili muscle expresses

sebaceous glands located between the follicle and muscle mass

stages of the hair cycle

anagen, catagen, telogen

anagen

hair matrix cells are mitotically active & hair is growing

catagen

regressive phase, mitotic activity slows down & the follicle migrates upward

telogen

resting or quiescent phase w/no mitotic activity/growth

external ear

is the pinna

pinna has

elastic cartilage, sweat and sebaceous glands

ceruminous glands

simple coiled tubular apocrine sweat glands of the inner surface of the ear pinna & the external auditory canal

cerumen

combination of sebaceous & ceruminous gland secretions known as ear wax

eyelids have

apocrine sweat glands

the junction in eyelids

mucocutaneous jxn btwn outer haired skin & inner conjunctival surface

anal sacs are

paired cutaneous diverticula

anal sacs are lined by

stratified squamous epithelium

circumanal glands

atypical skin glands located circumferentially around the anus

mammary gland is a

compound tubuloalveolar gland, aka a modified sweat gland

lobes

are groups of lobules w/considerable amt of CT btwn lobes

lobules

groups of tubuloalveolar secretory units surrounded by CT septa

alveoli

is the actual secretory unit

secretory epithelium of mammary glands

are simple cuboidal

lipids are released

by apocrine secretion

proteins are released

by merocrine secretion

milk is produced by

both apocrine and merocrine secretion

myoepithelial cells

contract in response to oxytocin forcing milk into the duct system

mammory gland ducts

intralobular ducts that drain lobulbes

mammory gland ducts converge

to form interlobular ducts which converge to for lobar ducts

mammory gland ducts vary from

simple cuboidal epithelium to stratified cuboidal epithelium surrounded by increasing amts of CT as the ducts become progressively larger

teat

has a hollow space known as the teat sinus which is continuous w/the gland sinus dorsally

teat is

continuous w/the teat canal ventrally

teat canal is

continuous w/the surface of the skin & is lined w/keratinized squamous epithelium