HMB200 L13; Feb. 28, 2012
Hypothalamus & Homeostasis (continued)
Produce own body heat; warm-blooded
5X bigger brains than reptiles due to internal body heat
Birds & mammals control body temperature near 37ºC.
Advantages: Constant physiology, better brain fn, bigger
brains, adaptation to extreme envts.
o Not envt’al temp dependent so brain & body doesn’t
slow down, so faster & better brain fn’ing allowing for
Costs: More insulation needed (fat, feathers, fur), more
energy needed, more internal controls.
Temp Control Systems
Temp maintenance – anterior nuclei
Cold-sensitive neurons in anterior hypothal
Metabolism of brown fat get warmer
Need recs for temp on skin, throughout body & in hypothal to
main body temp
Afferents: receive temp measurements
Neural regions: CPG – central pattern generator??
Effectors: heat regulation
Heat dispersal – posterior nuclei??
Accelerated respiration – ex. dogs
Dilation of cutaneous – pink skin
Perspiration - sweat
Body made up of ~65% H O, 2or cell chemistry,