CAS BI 107 Study Guide - Quiz Guide: Polysaccharide, Birth Weight, Estrogen
22 May 2017
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Homeostasis is the maintenance of a constant internal environment, which is vital for an organism to stay healthy. Fluctuations in temperature, water levels and nutrient concentrations could lead to death. Mammals and birds are warm-blooded they maintain a constant body temperature despite external environment changes. Human maintain a body temperature of 370c we have mechanisms to lose heat when we get too hot, and ways of retaining heat when we get too cold. The hypothalamus (part of brain) acts like a thermostat. It detects to of the blood running through it. If to > or < 370c, it sends electrical impulses, along nerves, to parts of the body which function in regulating body to. When you are cold, body produces and saves heat. Shivering: muscles contract and relax spontaneously ---> produces heat -- Vasoconstriction: arterioles near skin become narrower so little blood can flow through them (the blood flows through the deep-lying capillaries instead)---> conserve heat.
