BIOL 031 Lecture Notes - Lecture 32: Autocrine Signalling, Paracrine Signalling, Endocrine System
13 Aug 2020
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Document Summary
Changes in the membrane of a cell. Responsible for most communication within the body. Target signals, or targets, respond to signals. Local communication uses paracrine and autocrine signals: long-distance communication uses chemical and electrical signals. Form direct cytoplasmic connections between adjacent cells. Require interaction between membrane molecules on two cells. Act on the same cell that secreted them. Are secreted by one cell and diffuse to adjacent cells. Hormones are secreted by endocrine glands or cells into the blood. Only target cells with receptors for the hormone respond to the signals. Chemicals secreted by neurons that diffuse across a small gap to the target cell: not going to work w/o a receptor. Cytokines are peptides, synthesizes and secreted by all nucleated cells in response to stimuli. May act as both local and long-distance signals. In development and differentiation, cytokines usually function as autocrine or paracrine signals. In stress and inflammation, some may act on relatively distant targets.
