Epithelial Cells I Flashcards
What is the most cellular tissue in the body?
epithelial tissues
How many layers are in simple tissue?
one
How many layers are in stratified tissue?
more than one.
What are characteristics of epithelial cells?
uniform shape, tightly bound by junctions, little intercellular matrix, exposed to cavities/lumen
What are apical domains?
domains that are in contact with a lumen (I.e. Kidney tubule cells and glandular duct cells) or external environment(surface cells of the epidermis).
> They may have cilli.
What are basolateral domains?
> domains that are locked together by special junctional complexes with neighboring cells as well as the cells surface opposite the apical domain that is in contact with the basal lamina.
Where is the basal domain?
under the cell.
Epithelial tissues may be derived from?
> ectoderm (I.e., the skin epidermis and glands)
endoderm (I.e., the lining of the GI tract (including glands))
mesoderm (I.e., the lining of blood vessels, mesothelioma, Bowman’s castle)
Where do epithelial tissues receive nutrients?
diffusion from blood vessels.
What is the basal lamina?
> part of the basement membrane (basal layer) that is composed of type IV collagen plus glycoproteins and is PAS +.
It is absent in “leaky” epithelial tissue (E.g. lymph vessels and hepatic sinusoids).
It covers the epithelial cells.
What is the reticular lamina?
> part of the basement membrane below the basal lamina.
in contact with the underlying connective tissue and consists of argyrophililc fibers, reticular fibers and glycoproteins
What are the functions of the basement membrane?
> selective filtration barrier
scaffold for embryogenesis and regeneration
stabilization of tissue shape.
What do epithelial tissues line?
> body cavities and body surfaces.
They also form secretory/excretory parts of glands.
epithelial tissues may be innervated
What is a feature of squamous cells?
> They look squished or flattened
what is a feature of cuboidal cells?
they look like squares, and are in circles sometimes. The apical domain faces the center of the circle and the basal domain forms the outside.
What is a feature of columnar cells?
they look like rectangles and the nucleus is near the basal layer.
What are pseudostratified cells?
cells that appear to be simple epithelium (cells in contact with basal lamina) but appear stratified due to the different locations of nuclei in each cell.
What are transitional cells?
cells that appear to have more than one layer because of the position of the nuclei. The cells are in contact with the basal lamina, but dome shape gives it a stratified appearance.
What is polarity?
one side of the cell has a different function than the other side of the cell.
Where is simple squamous epithelium?
ducts, vessels, tubular structures (e.g. alveoli, Bowman’s capsule).
where is simple cuboidal epithelium?
contain microvilli sometimes. Found on surface of ovary, retina, kidney tubles, glands and ducts, bronchioles, choroid plexus and capsul of lens and eye.
where is simple columnar epithelium?
may have microvilli. Found on respiratory tract, uterine tubes, uterus, sinuses. Non-ciliated in the digestive tract, gall bladder and excretory ducts of glands.
Where is stratified keratinized squamous epithelium?
epidermis, cornea (keratinized);
Where is stratified cuboidal epithelium?
seldom found in the body; excretory ducts
Where is stratified columnar epithelium?
seldom found in the body; sweat glands, eye, male urinary tract, pharynx, epiglottis.
where is pseudostratified epithelium?
ciliated - trachea; stereocilia - epididymis
Where is transitional epithelium?
urinary system
What are the two kinds of epithelium?
covering/lining and glandular.
What are two functions of epithelium?
protection (stratified squamous) and maintenance of concentration differences with leaky and tight barriers; secrection and absorption (pseudostratified, simple columnar).
Simple non-ciliated columnar epithelium is associated with what tract?
Digestive tract
Transitional epithelium is associated with which tract?
urinary tract
stratified cuboidal is found where?
part of the male urethra, in excretory ducts, etc.
Where is non- keratinized stratified squamous epithelium found?
esophagus, mouth, tongue, vagina (non-keratinized).
Where is simple ciliated columnar epithelium found?
upper respiratory tract, sinuses, central canal of spinal cord.
Aside from layers, epithelial tissues can also be classified based on what?
> the predominant shape of the cells that make up the tissues
How are epithelioid tissues different from epithelial tissues?
> epithelioid tissues resemble epithelial tissues but lack a free surface
True or False: epithelial cells exhibit polarity?
> true
Do epithelial tissues contain blood vessels?
> no
Epithelial tissues sit on top of what?
> a basement membrane
What are the two components of the basement membrane?
> basal lamina
> reticular lamina
True or False: epithelial tissues may be innervated?
> true
