7 terms

negative feedback loop

Negative Feedback Loop
body senses a change an activates mechanisms to reverse it(dynamic equilibrium)
-Opposite actions happening to repair homeostatsis
ex) body temp. drops vessel constrict and shivering begins (heat gaining mechanism)
Negative feedback loop(human Thermoregulation)
*Brain senses change in blood temp.
-To warm: vessels dilate(vasodilation-widen) & warm blood flows closer to body surface an loses heat to surrounding air,if still hot sweating sweating begins(heat losing mechanism

-Too cold, Vessels in skin constrict (vasoconstriction-narrow) to retain warm blood deeper in body and reduce heat lost; is still cold, shivering(muscle tremor) begins(heat gaining)
Negative feedback of BP
sitting up in bed causes drop in BP in head and upper throax
-Baroreceptors(sensory nerve endings) in arteries near heart alert the cardiac center in brainstem
-Cardiac center(regulates heart rate) sends nerve signals that increase heart rate and return BP to normal
failure of this to feedback loop may produce dizziness in elderly
3 components of feedback loop
senses change in the body
ex)stretch receptors that monitor BP
-Integrating (control)Center
control center that processes that sensory information,'makes a decision', and directs the response
ex) cardiac center of brain
cell or organ that carries out the final corrective action to restore homeostatsis
ex) the heart(when speeds up to raise BP)