The body’s ability to detect change, activate mechanisms that oppose it, and thereby maintain relatively stable internal conditions.
State of the body fluctuates within limited range around a set point
The changes in our environmental conditions are called ______ because their values are not constant.
(i.e. hot or cold outdoor temp)
The part of the feedback mechanism that:
- Receives and processes information
- Relates it to other information
- Makes a decision of action to be carried out by the effector.
A structure, molecule or cell that detects a stimulus (or change in body variable)
The organ that carries out a response that changes the value of the variable
Ideal normal value of body temperature.
- Maintains homeostasis.
- Response to the original stimulus decreases.
- The response to the original stimulus INCREASES
- Mechanism that represents a cycle where physiological change leads to an even greater change in the same direction
Positive Feedback Example
- Head of fetus pushes againts cervix
- Nerve impulses from cervix transmitted to brain
- Brain stimulates pituitary gland to secrete oxytocin.
- Oxytocin stimulates uterine contractions and pushes fetus towards cervix.
Harmful Positive Feedback
Fever > 104°F
- Metabolic rate increases
- Body produces heat even faster
- Body temperature continues to rise
- Further increasing metabolic rate
- Cycle continues to reinforce itself
- Becomes fatal at 113°F