Lab 2 - Epithelium and Exocrine Glands Flashcards
what are the two major classifications of epithelia and where do you find them
- lining or covering epithelia = those that cover the body (epidermis), line a cavity (pleural cavity of thorax), or tube (GIT, blood vessel)
-glandular epithelia = formed by infolding of lining epithelia and are specialized for secretion
6 general characterisics of epithelia
-highly cellular tissue with little space between epithelial cells
-it has one free surface that borders the lumen, cavity or the outside world = apical surface
-the basal surface rests on the basal lamina which is an extracellular structure that separates it from underlying CT and anchors the epithelial layer to underlying CT
-can be made of a single or several layers but will collectively still have the apical and basal surfaces
- no capillaries within an epithelium, its avascular
-distribution of molecules and function is often polarized along the apical/basal axis of epithelial cells and organelles are often polarized along the apical/basal axis
what epithelium classification usually makes up the kidney in the cortex? where is there more vs less variation?
simple squamous or simple columnar
-more variation in the cortex (outside of kidney), less variation in medulla (inside)
what type of epithelium lines all of circulation in all organs?
simple squamous epithelium
what does PAS stand for and what does it bind
- periodic acid schiff
- it binds regions of the tissues with CHO
what is a defining trait of a PAS stain that can help you identify it?
the basal lamina will be more deeply stained comparted to other parts of the tissue
-also the apical surface can stain quite deeply as well. this is due to the glycocalyx (glycoprotein coating) that coats the microvilli on these cells
epithalia classification for skin side vs oral side of lip tissue
stratified squamous keratinized on skin side
stratified squamous non-keratinized on oral side
classification of sebaceous glands, what is the mode of secretion
simple branched acinar glands
holocrine mode
classification of apocrine sweat glands
simple coiled tubular
difference in storage of parotic vs pancreatic cells
proteins in the parotic gland secretions are not stored in the cell whereas in the pancreas it is stored
not storing the secretions gives the more uniform stain
What is the function of the tight junction?
in charge of sealing the apical from the baso-lateral comparment and for polarizing epithelial cells
what is the function of the adherence junction
holds the epithelial cells together and binds to actin myofilaments in the cytoplasm
what is the function of the desmosomes
responsible for very strong adhesion between cells and binds keratin intermediate filaments in the cytoplasm
what are the three parts of the apical junctional complex
tight junctions, adherence junctions, desmosomes
how are the cells held to the basal lamina?
adhesive junctions (focal adhesions and hemi-desmosomes
