ANHB1101 Lecture Notes - Lecture 33: Simple Squamous Epithelium, Basement Membrane, Basal Lamina
5 Sep 2018
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2 major cell types neurons and supporting cells. Epithelia covering and lining body surfaces + form the secretory glands portion of glands. Selective barrier (secretion, protection, transport, absorption and receptor function). Highest rate of cancer bc highly mitotic=more replications=more chance of mutations. Also has protective function so exposed to higher amounts of carcinogens=mutations. Origin; ectoderm, mesoderm, endoderm epithelium originates in all 3 primary germ layers. Apical domain faces free surface and specialisations may be present. Lateral domain specialisations to keep cells very closely packed and tightly bound: 3 types of cell junctions cells closely packed, tightly bound (+desmosomes), gap junctions. Controls what goes into cells and out of cells. Basal domain rests on basement membrane which is tightly bound. Basement membrane (basal lamina); physical barrier, molecular sieve (fibrous mesh. Determines what can and cannot pass through it), electrically charged to repel certain ions (ionic barrier). Exocrine maintains contact with surface (duct with epithelial lining).
