Homeostasis and Body Regulation

The body's ability to maintain stable internal conditions despite external changes.

A change inside the body, such as eating.

A change in the environment that affects the body, such as a rise in temperature.

Maintaining a stable body temperature (97-99°F) despite external temperature changes through responses like sweating.

Loss of body water, often as a result of increased sweating.

Detects changes in the body's internal or external environment.

Processes information from the receptor and sends commands to the effector.

Carries out the commands from the control center to restore homeostasis.

A biological process where the response to a stimulus reinforces the stimulus, creating a cycle that escalates until an external factor stops it.

Negative feedback mechanisms maintain homeostasis by reducing or reversing a change, while positive feedback mechanisms amplify a change.

Uterine contractions during childbirth are an example of positive feedback—stretching of the cervix triggers oxytocin release; oxytocin intensifies contractions, which increase stretching further. The process stops when the baby is born.

A rising fever is another example. Bacteria affecting the thermostat in the hypothalamus increase metabolic rate, which raises temperature further, setting off a cycle. This effect stops when white blood cells conquer the infection.

A characteristic of positive feedback where the effect of a stimulus continues to increase in a repeating loop.

Positive feedback mechanisms are less common in the body than negative feedback mechanisms, because they can cause harm by escalating the effects of a stimulus.

The response in a positive feedback mechanism intensifies (rather than counteracts) a stimulus.

A self-regulating process that reverses an initial change to maintain a stable internal state.

Maintaining a normal body temperature when it's too warm, through responses such as sweating and increased blood flow to the skin.

Sensory organs in the skin that detect changes in temperature.

Brain region that receives temperature information from receptors and sends signals to effectors.

Body parts that directly produce a response (e.g., blood vessels, sweat glands).

The rate at which the body uses energy to maintain function.

Brain region that plays a key role in regulating body temperature.

Gland in the neck that secretes hormones influencing metabolic rate.

Analogous system comparing the response of a home heating system to negative feedback in the body.

The change in air temp. used as a feedback for the heating system to maintain a stable temperature.