homeostasis Flashcards
homeostasis
“unchanging” dynamic state of equilibrium
internal conditions vary but within narrow limits
homeostatic control communication
nervous and endocrine systems
neural electrical impulses or blood borne hormones as info carriers
homeostatic control system
- stimulus- produces change in variable
- receptor- detects change
- receptor- - input- information sent along afferent pathway ro control center
- control center- - output- information sent along efferent pathway to effector
- effector - - response of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level
receptor
some type of sensor that monitors the environment and responds to changes (stimuli) by sending input to the control center
input
flows from the receptor to the control center along the afferent pathway
control center
determines the set point
set point
level or range at which the variable is maintained
output
flows from the control center to the 3rd component, the effector along the efferent pathway
afferent
info approaches the control center
efferent
info exits the control center
effector
provides means for the control center response to the stimulus
feedback
to influence stimulus either reducing or enhancing
negative feedback
output shuts off the original effect of the stimulus or reduces its intensity (most common)
opposite direction to that of the initial change
goal: prevent sudden sever changes within the body
positive feedback
the result or response enhances the original stimulus so the response is accelerated
same direction as the initial change
“cascades” infrequent events
ex. blood clotting
homeostatic imbalance
disease or disturbance of homeostasis
