epithelial tissues Flashcards
types of tissues
epithelial, connective, skeletal, and nervous,
epithelial tissue function
lining tissues that forms the boundary between out body and the external environment. PROTECTION, ABSORPTION, FILTRATION, SECRETION
where can epithelial tissue be found?
upper respiratory tract
what is the top surface of an epithelial tissue called?
free surface or apical surface
what is the bottom surface of an epithelial tissue called?
basal surface
what is the membrane underneath the basal surface called?
basement membrane
what type of tissues are epithelial tissues? (avascular or vascular)
avascular (no blood vessels)
how are epithelial tissues classified?
number of layers and the shape of the cell
classifications of epithelial tissues
simple epithelial tissue and striated epithelial tissue
squamous, cuboidal, and columnar
describe simple squamous epithelial tissue
single, flat layer of cells that is THIN and PERMEABLE
simple squamous epithelial tissue function
rapid diffusion of materials
where is simple squamous epithelial tissue found?
in blood vessels and lung tissues
describe simple cuboidal epithelial tissue
single layer of cube-shaped cells
simple cuboidal epithelial tissue function
secretion and absorption of substances
where is simple cuboidal epithelial tissue found?
in tissues of kidneys
describe simple columnar epithelial tissue
single layer of tall, closely packed cells. these cells may have cilia and goblet cells, which secrete mucus
simple columnar epithelial tissue function
secretion of mucus for protection and absorption of substances
where is simple columnar epithelial tissue found?
lining of digestive tract
describe stratified squamous epithelium
thick layers of squamous epithelium
stratified squamous epithelium function
provide protection for underlying layers
where is stratified squamous epithelium found?
in the epidermal layer of the skin
describe stratified cuboidal epithelium
more than one layer of cuboidal cells. rare in body
where is stratified cuboidal epithelium found?
in salivary and mammary glands
describe stratified columnar epithelium
free surface is lined with columnar cells. rare in body
where is stratified columnar epithelium found?
in larynx and male urethra
describe pseudo-stratified columnar epithelium
cell nuclei are found at different levels, so it appears stratified, though it is not
pseudo-stratified columnar epithelium function
secretion and absorption
where is pseudo-stratified columnar epithelium found?
in most of the upper respiratory tract
describe transitional epithelium
vary in appearance based on stretching of the tissue. “transition”: change shape with elasticity
where is transitional epithelium found?
in lining of urinary bladder
glandular epithelium function
specialized to produce and secrete substances
where is glandular epithelium found?
glands…
gland
group of cells that secrete a fluid substance
two ways to classify glands
complexity and how the substances are secreted (endo/exocrine)
exocrine glands
secrete substances outward through a tube-like duct
ex: sweat
endocrine glands
ductless glands that secrete hormones through the bloodstream so they can travel further distances.
packed tightly with capillaries running through the glandular tissue. cells excrete products through exocytosis.
ex: thyroid gland, thymus gland, adrenal glands, and pancreas
types of exocrine glands
merocrine, apocrine, and holocrine
merocrine exocrine glands
cells excrete the products via exocytosis
“mero”= part
ex: sweat glands
apocrine exocrine glands
a portion of the cell pinches off with secreted products
“apo”=tip
ex: mammary glands
holocrine exocrine glands
cells rupture and spill products into the duct
“hol”=whole
ex: sebaceous glands
