Epithelium and Glands (Histology) Flashcards
define tissues
aggregates of cells organised to perform specific functions, through a distinctive pattern of organisation
what are the four types of tissue?
- epithelium (body surfaces, cavities and glands)
- connective tissue (support)
- muscle tissue
- nerve tissue
how do you the four different types?
morphology: epithelial and connective
function: muscle / nerve tissue
what is epithelium derived from?
ectoderm and endoderm (early embryonic layers
which parts of body arent covered by epithelium?
articular cartilage, tooth enamel and anterior of iris
what are the functions of the epi?
- protection (skin)
- detection
- sensation
- regenerative capacity
- absorption (intestines)
- material transport (cilia)
- gas ex (alveolus)
- excretion
9 secretion (glands)
describe the surface of the epithelium tissue
have a free surface - top surface is free.
describe how epi cells are bound
bound by contiguous sheets - joined by cell to cell junctions
how are epi cells renewed?
by mitosis
how do epi tissue get nourishment and oxygen?
AVASCULAR
nourishment and O2 derived from underlying connective tissue
what is epi tissue supported by? what does this do
BASEMENT MEMBRANE - non cellular protein-polysaccharide rich tissue
separates the epithelial from the connective tissue.
what is free surface aka?
apical domain
what is difference in simple and stratified epithelial tissue?
simple = one cell layer
stratified = multiple layers
how are epi cells named with regards to shape?
squamous: flattened (squeezed)
cuboidal: rectangular
columnar: longer than is wide
how do u classify epithelium cells?
- number of cells
2. cell shape
where do you find transitional cells?
lower urinary tract
describe the structure of transitional cells?
stratified epithelium cells
whats special about transitional cells?
at the top, the cells look dome shaped - look inflated.
why?
when bladder is full, it allows the tissue to extend - the cells become flat.
what are pseudostratified cells?
appears stratified but they are actually simple due to location of the nucleus. one cell has nucleus close to membrane, but others are further up - give the illusion of multiple layers
where do you find pseudostratified cells?
trachea