BIOL 240 Lecture Notes - Lecture 19: Brown Adipose Tissue, Ectotherm, Thermostat
13 Nov 2018
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Document Summary
Some mammals have a tissue called brown fat that is specialized for rapid heat production. Activation of brown fat in human adults has been found to vary depending on the temperature of surrounding environment. Birds and mammals can vary their insulation to acclimatize to seasonal temperature changes. Dogs gain more fur in the winter. Lipid composition of cell membranes may change with temperature to keep membranes intact. When temperatures are subzero, some ectotherms produce antifreeze compounds to prevent ice formation in their cells + potential bursting of their cells. Thermoregulation in mammals is controlled by a region of the brain called the hypothalamus. The hypothalamus triggers heat loss or heat-generating mechanisms. Fever, a response to some infections, reflects an increase in the normal range for the biological thermostat.
