MCDB 1B Lecture 1: Animal Physiology
6 Mar 2018
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How cells communicate with each other via electrical signals through the nervous system. Irisin - converts white fat into brown fat, secreted when muscles are exercising. Brown fat - metabolizes lipids to produce heat without producing atp. Brown fat is inversely proportional to body mass. Irisin starts the "browning" of white fat to brown fat and the conversion of brown fat to atp. Mimics testosterone and binds to receptors, alters gene expression. Greatly increased risk of cancer, heart, liver and kidney disease. Hormones are chemical messengers (signals) that allow slow communication between distant cells in the body. Hormones act on a time scale of several seconds to days. They secrete hormones into the interstitial space (extracellular fluid) and/or bloodstream. Hormones travel in the bloodstream and bind to receptors on distant target cells. Only affect cells that have the correct hormone receptor. Paracrine/autocrine hormones - immune system produces a lot of these.
