BIOL 1082 Lecture Notes - Lecture 17: Brown Adipose Tissue, Circadian Clock, Torpor
Document Summary
Homeostasis and temperature regulation (reading: concepts: 40. 2-40. 4 in textbook: define homeostasis, and explain how feedback control is used to maintain it. Homeostasis, which means steady state, referring to the maintenance of internal balance. In achieving homeostasis, animals maintain a relatively constant internal environment even when the external environment changes significantly. Negative feedback is a control mechanism that reduces, or damps, the stimulus. (ex: when you exercise you produce heat which increases body temp. so your nervous system detects this and triggers sweating) Positive feedback is a control mechanism that amplifies rather than reduces the stimulus. In animals, positive feedback loops do not play a major role in homeostasis, but instead help drive processes to completion. (ex: contractions during child birth: define how organisms can be categorized with respect to temperature regulation. Endothermic organisms are warmed mostly by heat generated by metabolism. Mammals, birds, a few nonavian reptiles, some fishes, and any insect species are mainly endothermic.
