BIO 167 Lecture Notes - Lecture 4: Glycosaminoglycan, Urethra, Elastic Fiber
26 Apr 2021
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Groups of cells similar in structure and perform a common or related function. Has a apical surface and a basal surface(polarity) Tightly packed cells held together by junctional complexes (tight junctions and desmosomes) I. e. thicker tissue provides for better protection. Transitional: shape changes as organ stretches or relaxes. Bowman"s capsule (kidney), alveoli (lungs), endothelium (bv) Forms wall of renal tubules & ducts of small glands. Nuclei tend to line up toward basal surface. Tubular glands secrete mucus containing intestinal juice. All cells in contact with basement membrane. Not all cells reach the free surface. With cilia: in trachea; f(x) secretion, move substances along free surface. With stereocilia: epididymis; f(x) secretion & absorption. Basal cells divide, cells migrate to surface. Free surface squamous, deeper layers cuboidal or columnar. Keratinized: skin, cells lack nuclei at free surface (fs) Nonkeratinized: lines mouth & esophagus, has nuclei present at fs. Cells farthest from basal layer less visible.
