PHSC 4340 Study Guide - Final Guide: Thyrotropin-Releasing Hormone, Insulin Receptor, Chronic Kidney Disease
29 Dec 2016
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Document Summary
Insulin is a polypeptide hormone secreted by beta-cells of the pancreas"s islets of. Insulin is stored in beta-cells and made from a precursor protein, pro-insulin. A beta-cell releases insulin when stimulated by glucose. Glucose enters the cell and triggers a cascade of biochemical events that increase cytoplasmic concentration of calcium: one event triggered by glucose is the closure of k channels opening of. Ca channels influx of ca into the cell increases cytoplasmic ca concentration stimulates insulin release. First released into portal circulation and when it reaches the liver about gets degraded and the rest gets into systemic circulation. In systemic circulation, insulin circulates unbound to plasma proteins. In peripheral tissues, insulin binds to its own receptors on the plasma membrane. Triggers a series of biochemical events including the insertion of glucose transporters into the cell membrane. Effects are countered by other hormones such as epinephrine, glucagon, gh and cortisol. Liver insulin stimulates storage of glucose as glycogen.
