Cells160-page24

Cells160-page24 - the cytoskeleton. Many epithelial cells...

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Cell - 24 Cell-to-Cell Attachment and Communication Cells typically have methods of "physically" communicating with adjacent cells using a variety of cell membrane connections. These connections are often called cell junctions. There are three common types of cell junctions found in animal cells, as well as the plasmodesmata of plant cells just discussed. Tight Junctions Tight junctions are composed of protein fibers that seal adjacent cells to prevent leakage, something that can be useful in organs such as the bladder and the lining of the digestive tract. Tight junctions literally fuse the cells together forming a sheet of cells that can restrict molecules to one side of the sheet or the other. Desmosomes (Adhering Junctions) Desmosomes anchor adjacent cells together by making connections that work like staples or rivets that attach to components of
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Unformatted text preview: the cytoskeleton. Many epithelial cells must adhere to adjacent membranes to prevent free passage or free movement, and to not break apart under stress. Desmosome filaments are composed of specialized glycoproteins. Intermediate filaments of keratin in the desmosomes help strengthen the junction. Actin microfilaments can also attach to desmosomes, but have less strength. Gap Junctions (Communicating Junctions) Gap junctions are protein channels between adjacent cells that permit the transfer of small molecules between the cells. They are common in brain cells, forming the synapse, in many glands, and in cells in the heart muscle that coordinate contraction for heartbeat. The plant plasmodesmata, discussed previously, are a plant communicating junction....
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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