Cheatography
https://cheatography.com
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This is a draft cheat sheet. It is a work in progress and is not finished yet.
general features of epithelium
covers body surfaces & lines body cavites |
composed almost entirely of sheets of closely packed cells |
very little intracellular space and extracellular material |
no blood vessels: avascular |
renewal: capacity to regenerate: good thing: balance cell death and cell proliferation |
-more cell death than formed: ulcer -more cell formed: cancer |
--most likely location of epi to get damaged is skin |
epithelial cells are often strongly connected by junctions. |
originate from 3 primary germ layers(eco,endo,meso-derm) |
polarity: diff area diff structure: apical side (the area of an epithelial cell adjacent to the exterior or to body cavity ) opp area=basal; side |
ALWAYS supported by a layer extracellular matrix know as basement membrane. |
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BM: basement membrane or basal lamina
BM=interwoven network of laminin & collagen IV (4) attached by nidogen/entactin and proteoglycan |
epithelial cell membrane attached via integrins to laminin. |
ll=lamina lucida: less fiber |
LD: lamina densa |
-proteoglycan rich in cards: positive to pas Shiff... |
function of epithelium
protection |
absorption |
secretion |
transportation |
filtration |
sensory reception |
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types of epithelia
based on number of cell layers |
or shape of cells in apical layer |
1 layer: simple |
1. squamous=flat, scale like |
more than 1: stratified. |
2. cuboidal=cube-shaped |
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3.columnar=column-shaped |
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