7 terms

negative feedback loop

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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
*Receptor-s
*Integrating(control)Center
*Effector
-receptor
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
Effector
cell or organ that carries out the final corrective action to restore homeostatsis
ex) the heart(when speeds up to raise BP)
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