Homeostasis and Body Regulation

Vocabulary flashcards covering principles of homeostasis, survival needs, feedback systems, and specific physiological examples.

Homeostasis

The ability of the body to maintain a relatively constant internal environment, the disruption of which is the basis for disease and death.

Factors for Survival

Essential requirements that must be present in appropriate amounts for human survival: nutrients, oxygen, water, normal body temperature, and appropriate atmospheric pressure.

Regulated Variable

The specific variable that is maintained and kept stable by the body.

Set Point

The expected target value of a regulated variable in a homeostatic system.

Receptor

A sensory structure that detects a change or stimulus and sends information along an afferent pathway to the control center.

Control Center

The body component (usually the brain) that receives input from receptors and orchestrates an appropriate response to return a variable to its set point.

Effector

A body component that receives output from the control center along an efferent pathway and carries out appropriate physiological adjustments.

Afferent Pathway

The pathway along which sensory input about a detected change is transmitted from a receptor to the control center.

Efferent Pathway

The pathway along which output signals are sent from the control center to an effector.

Negative Feedback

The primary homeostatic mechanism in which the response of the effector counteracts or opposes the original stimulus.

Positive Feedback

A regulatory mechanism in which the effector response reinforces and moves in the same direction as the original stimulus, requiring a shut-off mechanism.

Feed Forward

A regulatory mechanism where the body anticipates a physiological need and resets the set point before an actual change in the regulated variable occurs.

Internal Environment Regulation

The mechanism by which control systems maintain small internal fluctuations in body cells despite large external environmental fluctuations.

Body Temperature Regulation via Negative Feedback

A homeostatic process where elevated blood temperature causes blood vessels to dilate and sweating to occur, whereas low blood temperature causes blood vessels to constrict and sweating to cease.

Corrective Action in Negative Feedback

The response triggered when a disturbance causes a deviation from the set point, working to counteract the change and return conditions toward optimal levels.

Positive Feedback in Lactation

A pathway where baby suckling triggers sensory receptors to signal the hypothalamus, prompting the posterior pituitary to release oxytocin to cause milk ejection.

Positive Feedback in Ovulation

A mechanism where estrogen secretion by the ovaries drives LH secretion from the pituitary gland, which further enhances estrogen release until ovulation occurs.

Feed Forward Salivation

The production of saliva stimulated simply by thinking about a meal, anticipating digestive needs and resetting the set point prior to food intake.