ANSC 3080 Study Guide - Final Guide: Glycosuria, Hydrophile, Glycogen
Document Summary
Hormones: regulatory chemicals produced in an endocrine gland or scattered cells, secreted into the blood and carried to its target cell that responds by altering its metabolism. Carrier proteins are big: keep hormones in vessel, prevent hormone degradation: hormone + carrier hormone- carrier. In the case of thyroid hormones, hhr already in the nucleus. Intracellular receptors require ligands that are membrane permeable and include receptors for steroid hormones, lipophilic vitamins, and small molecules such as nitric oxide and hydrogen peroxide. Action of cell surface receptors: cascade of intracellular messengers amplifies the signal several thousand times, specific effects on target cells depend on the type and amount of messenger activated. Immediate effects: enzyme activation, exocytosis: slow effect: stimulation of gene transcription, de novo protein synthesis, after signalling, receptor-hormone complex is internalised, fuses to lysosome and is degraded, dissociates and receptor is recycled to the cell surface. Hypothalamo-pituitary axis: hypothalamus is the major integration center.