Homeostasis Flashcards
Explain the importance of physiological control systems
If disruption is too severe or homeostasis is crucial to survival, death will result
BALANCE
Explain the meaning of homeostasis
Physiological control systems maintain a relatively stable internal environment (i.e., within safe limits or a “normal range”) in a fluctuating environment
Example of negative feedback
blood pressure
Thermoregulation
Example of positive Feedback
Blood clotting
Oxytocin
Example of feedforward control
Digestive system
What percentage of fluid is ECF and ICF
70%ICF
30%ECF
Nervous response to homeostasis
quick, short duration response
endocrine response to homeostasis
long, longer duration response
Open Loop:
controller - controller component - output
THIS OUTPUT NOT INFLUENCED BY RESULTING CONDITIONS
Can result in run away reactions if there is no termination
Closed Loop:
Controller - controller component - output - sensor - feedback - controller
INFLUENCED BY RESULTING CONDITIONS
negative feedback
returns to set point
feedforward
response is generated in anticipation of change
positive feedback
moves away from set point
negative feedback control of arterial BP
baroreceptors (stretch receptors in carotid arteries and aortic arch) are SENSOR
nucleus in medulla oblongata references set point and notices change in bp CONTROL CENTRE
EFFECTORS
CONTROLLED = rise or fall in BP
SENSOR
Gain
degree of effectiveness of a negative feedback control system
= Correction/error