IB Sports, exercise and health science A.1.2.1 Mechanisms and Processes Maintaining Homeostasis Key Definitions

A structure in the heart that delays electrical impulses to allow the atria to contract before the ventricles.

A part of the heart’s conduction system that transmits impulses from the AV node to the ventricles.

A specialized cell or structure that detects changes in the internal or external environment and sends signals to the control center.

A structure (e.g., muscle or gland) that responds to signals from the control center to restore homeostasis.

The production of glucose from non-carbohydrate sources, such as proteins and fats.

The process of converting glucose into glycogen for storage, mainly in the liver and muscles.

The process of breaking down glycogen into glucose to be released into the blood for energy use.

Homeostasis is the maintenance of a stable internal environment within an organism, ensuring optimal conditions for cellular processes.

Negative feedback is a homeostatic mechanism in which a change in a physiological condition triggers a response that counteracts the initial change, maintaining balance.

pH is a measure of hydrogen ion (H⁺) concentration, determining how acidic or basic a solution is.

The process of hair standing up (goosebumps) to trap heat.

Positive feedback is a physiological mechanism in which a change in a condition leads to an amplified response, moving further away from homeostasis.

Specialized fibers in the heart that distribute electrical impulses to the ventricles, ensuring coordinated contraction.

The heart’s natural pacemaker, responsible for initiating electrical impulses that regulate heartbeat.

Thermoregulation is the process by which the body maintains its internal temperature within a narrow range through physiological and behavioral responses.

The narrowing of blood vessels to reduce blood flow and conserve heat.

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