BLG 10A/B Study Guide - Final Guide: Basal Lamina, Epithelial Polarity, Tight Junction
29 Dec 2015
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Document Summary
All specimens must be fixed (preserved), cut into thin sections and stained. The stains used in light microscopy are dyes; the stains in electron microscopy are heavy metal salts. Artifacts: minor distortions that alter the tissue"s original condition. Definition: a sheet of cells that cover a body surface or line a body cavity. Covering and lining epithelium: forms the outer layer of the skin, lines the open cavities of many systems and covers the walls of the closed ventral cavity. Glandular epithelium: fashions the glands of the body. Special characteristics of epithelium: polarity: all epithelia contain an apical surface and a basal surface. All epithelia exhibit apical-basal polarity, i. e. the cell regions near the apical surface differ from those near the basal surface in structure and function. Most apical surfaces have microvilli (for absorption) and some have cilia (to propel substances along their free surface)
