epithelial tissues- physiology

what differentiates pseudostratified columnar from simple columnar?

pseudostratified has more than one layer

histology

study of tissues

cuboidal

cube shaped

columnar

columns

squamous

flat

simple

one layer

stratified

multiple layers

2 characteristics used to classify epithelial tissues

number of layers and shape

2 tissues that don't conform to the naming classification rules

transitional and pseudostratified

stratified epithelial tissue may have different cell shapes from the basal layer to the apical layer. which layer determines the shape of the tissue?

apical (top) layer

name this type of tissue: a tissue consists of multiple layers of cells, the top layer is composed of columnar cells

stratified columnar

the majority of dust is composed of human skin cells (stratified squamous epithelium). what does this indicate about the rate of mitosis for epithelial tissues?

rapid

avascular

no blood/blood vessels running through tissues (will have to diffuse through to get to nutrients)

function of epithelial tissues

protection, secretion, absorption, excretion

location of epithelial tissues

covers organs/body; lines body cavities/hollow organs

characteristics of epithelial tissues

free surface, basement membrane, avascular, cells rapidly divide, cells are tightly packed, cells can have desmoses.

simple squamous description

simple layer of flat cells, substances pass easily through (absorption of O2)

simple squamous location

alveolar lung air sac, capillary

simple squamous function

diffusion, filtration

simple cuboidal description

single layer of cube shaped cells

simple cuboidal location

sweat glands, thyroid

simple cuboidal function

absorption, secretion

simple columnar description

single layer of elongated cells, nuclei usually near the basement, membrane at same level, sometimes passes cilia & microvilli, goblet cells (mucus)

simple columnar location

stomach, duodenum

simple columnar function

absorption, secretion

pseudostratified columnar description

single layer of elongated cells (wedge together to appear as there are 2+ layers), nucleus has 2+ layers, appear striated, often have cilia, often have goblet cells

pseudostratified columnar location

male sperm duct, trachea

pseudostratified columnar function

propulsion (move chemicals)

stratified squamous description

several layers of closely packed cells, top cells are flat, can accumulate keratin (become harder)

stratified squamous location

skin, mouth

stratified squamous function

protection

goblet cells

produce mucus

cilia

projections from cell surfaces that aid in locomotion and feeding; also used to sweep substances along surfaces

transitional location

urinary bladder, urethra

transitional function

stretching

tight junctions

-close space between cells

-located among cells that form linings

desmoses

form "spot welds" between cells, located among outer skin cells

gap junctions

tubular channels between cells, located among outer skin cells

endocrine glands

ductless (key word: hormone), secrete products into tissue fluid/blood

exocrine glands

have ducts, secrete products into ducts that open on a surface

unicellular exocrine gland

goblet cell

multicellular exocrine glands

sweat glands, salivary glands, etc. (simple & compound)

taking in, taking out

the path a chemical moves in for absorption and secretion

primary epithelium

covers and lines your outer and inner body

glandular epithelium

forms your glands and secretes hormones and other substances

invagination

the action/process of being turned inside out/folded back on itself to form a cavity/pouch

polar (all epithelial tissues)

they have distinct size

apical

upper

basal

inner surface

basement membrane

thin layer of mostly fibers that helps hold the epithelium together and helps it anchor to the next deeper layer

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