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WorksheetsHomeostasis and Feedback Mechanisms
Total questions: 20
Worksheet time: 10mins
Homeostasis refers to:
Maintaining constant external environment
Maintaining stable internal environment
Maintaining body temperature only
Control of hormones only
Primary regulator of homeostasis:
Endocrine system
Skin
Autonomic nervous system
Skeletal muscle
Negative feedback aims to:
Reinforce change
Oppose change
Stop regulation
Create instability
Example of negative feedback:
Parturition
Blood clotting
Regulation of BP
Ovum release
Example of positive feedback:
Thermoregulation
Blood clotting
Control of glucose
Maintenance of BP
In positive feedback:
Output decreases stimulus
Output increases stimulus
No effect on stimulus
System shuts down
Feed-forward regulation:
Occurs after change occurs
Anticipates change
Never involves CNS
Opposes feedback
Example of feed-forward mechanism:
Thermoregulation
Salivation before food intake
Stretch reflex
Renin secretion
Integrator in homeostasis is:
Receptor
Effector
Control center
Cortex
Receptor detects:
Response to stimulus
Stimulus change
Output signal
Set point
Set point is:
Lower limit of function
Desired value maintained
Upper limit only
Threshold of pain
In BP regulation, baroreceptors act as:
Effectors
Receptors
Integrators
Motor pathways
In temperature regulation, sweating is:
Receptor response
Integrator response
Effector response
Neural inhibition
Failure of homeostasis leads to:
Adaptation only
Disease
Better function
Hypertrophy only
In negative feedback, effector acts to:
Amplify stimulus
Stabilize variable
Reset set point permanently
Stop receptor function
Positive feedback can be terminated by:
Enhancing stimulus
Removal of stimulus
Increasing output
Increasing gain
Gain of feedback system is:
Output/Input
Correction/Error
Set point × change
Error × output
High gain system:
Is unstable
Corrects deviations efficiently
Does not correct errors
Shows no change
Homeostasis mainly depends on:
Stable external temperature
Stable external pressure
Internal regulatory mechanisms
Only hormones
Feed-forward improves:
Speed of response
Accuracy of receptors
Set point value only
Strength of stimulus
