KNES 259 Lecture Notes - Lecture 6: Tight Junction, Cell Junction, Cell Membrane
11 Sep 2020
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Document Summary
Cell junctions are contact points between plasma membranes of tissue cells. Most epithelial, some muscle and nerve cells are tightly joined into functional units by cell junctions. Inhibit leakage from one region of body to another by inhibiting leakage through cells. Regions where you don"t want leakage are: intestines (leakage of digestive enzymes that chemically breakdown food. Don"t want them to move away from lumen of the gi tract through cells to blood vessels because then those enzymes digest blood vessels, which is de nitely not a good thing) Strands of junctional proteins come together at kiss sites, causing fusion of outer surfaces of plasma membranes of adjacent cells, which blocks passage ways between cells. Membrane proteins (connexins, many of them make connexons) involved, that join together to allow movement of ions (important in communication and transmission of charge) from cell cytosol of one cell to another. Connexons provide passageway for movement of one molecule between cells.
