homeostasis Flashcards
what is homeostasis
the body’s natural ability to maintain a stable and balanced internal environment.
variables of maintenance of homeostasis
blood glucose
blood pressure
ion balance
water balance
important contributes to homeostasis
endocrine and the nervous system as they allow communication through the body.
mechanisms for maintaining homeostasis
restores normal state of the body after it has been disturbed
often maintained mainly through principle of feedback loop
feedback loop
A control system that acts to maintain the level of some variable within a given range following a disturbance.
when the body is in homeostasis
the set level of all variables are within physiological range.
there is a dynamic balance (no difference) between the set level and the input as the comparator an output to target organs.
augment
to make something greater by adding to it
comparator
compares current value to a desired value
control centre
determines a set point (level or range) information travels from the control centre to the effector along efferent pathway.
effector
usually the target organ, provides a mean for the control centre to influence a response to the stimulus.
Endocrine
secretion from a gland or cell into the interstitial fluid or systemic circulation, to have its effect at a distant target.
physiological range
range of values of a selected population with no known pathology related to that measurable variable.
stimulus
a change occurs in the internal or external environment that disturbs homeostasis
sensors
monitor the environment that disturbs homeostasis
vasoconstriction
decrease in size of the lumen of a blood vessel caused by the concentration of vascular smooth muscle in the wall of the vessel.
feedback loops are dynamic
if there is a difference in the set level and input at the comparator, an output to target organs will modulate the variable.
controlled variable
can be influenced by external factors
feedback communication
communication between components of the system is known as feedback which can have a positive or negative effect on the output from the control centre.
negative feedback
when a change occurs in the opposite direction to the original stimulus.
a decrease in function in response to a stimulus
positive feedback
when change occurs in the same direction as original stimulus.
an increase in function in response to a stimulus.
cell to cell communication
electrical and chemical signals
long distance communication
electrical and chemical (neurotransmitters and hormones)
intracellular signalling pathways
chemical signals activate a receptor, translate chemical signals to cellular signals and create a response.
