BIOL 110-111 Chapter Notes - Chapter 4: Adherens Junction, Tight Junction, Cell Junction
26 Sep 2016
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Document Summary
A cell junction is a point of contact between the plasma membrane of tissue cells. Tight junction: web-like strands of transmembrane proteins fuse together the outer surfaces of the membranes, forms a tight seal to inhibit the passage of the contents of the tissues from leaking. Adherens junction: contains plaque, which is a dense layer of proteins that adheres to the insides of both plasma membranes, helps epithelial cells resist separation during contractile activities. Desmosomes: plaque attaches to the intermediate filaments inside the two cells to help with the tissue"s stability, found in epithelial cells to prevent from separating and in cardiac muscle cells for when the heart contracts. Hemidesmosomes: resemble half of a desmosome, but it anchors epithelial cells to the basement membrane. Endocrine glands secrete hormones that diffuse directly into the bloodstream or interstitial fluid without flowing through a duct.
