Homeostasis is the manifestation of the characteristic of life known as irritability and responsiveness.





The overwhelming number of homeostatic reactions are facilitated by negative feedback loops. Negative feedback loops have “negative” effects on the stimulus. They “reverse” the stimulus.



The roles of receptor, control center, and effector are not necessarily consigned to one structure.

For instance if a receptor is only sensitive to a change in temperature, then a control center would be required to determine the direction of the change (warmer or cooler)


However if the receptor is only sensitive to a decrease in temperature then there is no need for a control center as the receptor is performing both roles.



Negative feedback loops help maintain a physiological dynamic equilibrium which facilitates a relative internal steady state within optimal limits.



In contrast to negative feedback loops there are a few positive feedback loops.

Positive feedback loops ultimately increase or enhance the stimulus.

Positive feedback loops are most readily described in:


Blood vessel repair

Labor and delivery




-CHECKPOINT-



This is a good time to pause

and assess your knowledge of key concepts.

Below are links to a few

learning activities that might

assist your mastery of the material.


Completing some of the tasks

may also earn you class

participation credit!


However, most importantly it

will assist in your learning.

You should attempt to

complete the assignments

without using your text,

notes, etc., as they are

designed to test your

knowledge—just like taking

a test in class—but

without the grade consequences.


Tasks include mock exams,

games, clinical scenarios,

and more. Click/tap on

the activities and see how

much you know!


Homeostasis Match