protection from outside or inside (organ contents; ex stomach)

secretion

absorption

sensory

transport

where it came from:

ectoderm, endoderm, mesoderm

shape

cell-cell junctions

cell basement membrane junctions

respiratory

gastrointestinal

endothelial cells around blood vessels

mesothelium: body cavities

squamous: flat

cuboidal: cube

coumnar: rectangle

simple: 1

stratified: 2 or more

pseudostratified: all cells touch basement membrane and extend to top so it's one layer, but nuclei are randomly distributed so it looks stratified

short

hard to see: pink "brush border"

non motile

inc absorption surface area

only on simple or pseudostratified epithelia: must reach basement membrane to move fluids etc to other side

long

easier to see

motile

also only on simple or pseudostratified epithelium

long micorvilli

rare - epididymus and inner ear

not found on epithelia

similar to columnar cells

wide top, narrow base

granular cytoplasm

unicellular gland: secrete mucus

only on simple or pseudostratified

fragile: protected areas

examples:

line blood vessels

line body cavities

caudal surface of cornea

kidney tubules (loop of henle)

deepest layers are more cuboidal, become more flat toward top

continual replacement/sloughing

pigment: in basal layers

examples:

oral cavity & pharynx

esophagus

anal canal

uterine cervix, vagina

cranial/ rostral cornea surface

only in stratified squamous epithelium

superficial cells die and leave behind tough skeleton

more friction resistance

orthokeratosis: lose nuclei

parakeratosis: retain nuclei

examples:

skin

oral cavity, esophagus, forestomach (ruminants)

examples:

kindey tubule/ nephron (+ microvilli)

pancreas

salivary gland

ducts (tubular)

uncommon

examples:

salivary ducts

apocrine ducts

nuclei lined up apical vs basal

can have microvilli and/or goblet cells

examples:

intestines

gall bladder

most but not all cells will have cilia

can have goblet cells

female reproductive tract

usually have cilia and/or goblet cells

example:

respiratory tract

bottom/ basal layer usu more cuboidal

rare

examples:

conjunctiva, salivary gland duct

changes based on how stretched or relaxed it is

relaxed: more stratified cuboidal

stretched: more stratified squamous

resists urine

examples:

bladder, ureters, urethra

only in urinary tract

secretes directly into the blood stream - no duct

examples:

thyroid, pituitary, pancreas (Islets of Langerhans)

goblet cells (exocrine)

enterochromaffin cells in GI (endocrine)

dumps secretions into a duct

almost always simple culboidal

DUCT does not branch

secretory component may or may not branch

Duct branches

secretory component will usually also branch

cells of secretory component are arranged on a tube

shapes: straight, coiled, branched

secretory cells are arranged around a sphere

examples:

pancreas

salivary gland

combination

examples:

salivary gland (can be either compound alveolar or compound tubuloalveolar)

mammary glands

membrane bound secretory vesicles form in the cytoplasm & fuse with luminal cell membrane to release contents outside the cell

can't be seen on microscope

mucus or serous

examples:

salivary

pancreas (exocrine)

eccrine glands

membrane bound peices of apical cell pinch off

can be seen rarely on microscope

examples:

mammary gland

apocrine / epitrichial gland

ceruminous (ear wax)

entire CELL falls off and becomes secretory product

can be seen on microscope

examples:

fat

skin

eyelids

sebaceous

watery

cells can have apical pink/eosinophilic granules

round nucleus

examples:

pancreas

salivary gland

viscous

foamy cytoplasm

nucleus of secretory cells displaced basally, flattened

examples:

GOBLET cells

salivary gland

stomach (body and pylorus)

between secretory cells and basement membrane

contract to move secretions from acinus to duct or further