2 Homeostasis and Feedback Mechanisms

Homeostasis

The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes.

Feedback Mechanisms

Systems that detect internal and external conditions and initiate corrective actions to maintain homeostasis.

Negative Feedback

A primary mechanism of homeostasis where a change in the environment triggers a response that counteracts that change.

Integrator

The processing or control center in a feedback mechanism that compares environmental conditions with optimal conditions.

Effector

An organ or cell that acts in response to a stimulus to bring about a change.

Set Point

The optimal value for a given variable of a system, such as body temperature.

Thermoregulation

The process of maintaining body temperature within a narrow, optimal range.

Positive Feedback

A feedback mechanism that enhances or increases the changes triggered by a stimulus, often leading to a larger response.

Oxytocin

A hormone released during childbirth that increases uterine contractions, leading to the delivery of the baby.

Vasodilation

The widening of blood vessels to increase blood flow and allow heat loss.

Vasoconstriction

The narrowing of blood vessels to minimize blood flow and retain body heat.

Adrenaline

A hormone released in response to stress that prepares the body for a 'fight or flight' response.

Thermoreceptors

Specialized nerve endings that detect changes in temperature.

Hypothalamus

The brain region that acts as the integrator in thermoregulation, comparing temperature signals to set points.

Sweat Glands

Effector organs that help cool the body by secreting sweat, which cools the body through evaporation.

Stimulus

Any change in the environment that disrupts homeostasis.

Negative Feedback Loop

A system in which the output of a process reduces the initial stimulus, thus maintaining homeostasis.

Blood Clotting

A positive feedback process where factors are released to promote and accelerate the clotting mechanism.

Fight or Flight Response

A physiological reaction to perceived harmful events, attacks, or threats, requiring the release of hormones.

Contraction

The tightening or shortening of muscles or organs, as seen in uterine contractions during childbirth.