IB Sports, exercise and health science A.1.3 Transport Key Definitions

Alveoli are tiny, balloon-like structures that are the primary site for the exchange of gases (O₂ and CO₂). They provide a large surface area for gas exchange due to their many folds.

The difference in oxygen content between arterial and venous blood, indicating how much oxygen is extracted by muscles during circulation.

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

The primary form of carbon dioxide transport in the blood, formed when CO₂ combines with water.

Blood pressure (BP) is the force exerted by blood on artery walls, measured in mmHg.

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

The volume of blood the heart pumps per minute.

Cardiovascular drift is the gradual increase in heart rate (HR) observed during prolonged submaximal exercise, typically when the body is exposed to heat or thermoneutral conditions.

The phase of the cardiac cycle when the heart relaxes and fills with blood.

Diastolic BP is the pressure during heart relaxation when the heart is filling with blood.

The passive movement of a gas from an area of higher partial pressure to an area of lower partial pressure. It is the mechanism by which oxygen and carbon dioxide move between the alveoli, blood, and tissues.

The additional amount of air that can be exhaled after a normal breath.

Gas exchange refers to the movement of oxygen into the bloodstream at the lungs and carbon dioxide out of the bloodstream for exhalation.

Hematocrit is the percentage by volume of red cells in your blood

An iron-rich pigment in red blood cells that binds oxygen in the lungs and transports it through the blood to the body's tissues, and helps return carbon dioxide to the lungs.

Heart rate is the number of times the heart beats per minute (bpm). It reflects how fast the heart pumps blood to meet metabolic demands.

The vein that carries absorbed nutrients from the small intestine to the liver for processing.

The additional amount of air that can be inhaled after a normal breath.

Minute ventilation is the total volume of air that is inspired or expired from the lungs per minute.

The volume of air that remains in the lungs after a maximal exhalation. It cannot be voluntarily expelled and keeps the alveoli from collapsing.

Respiratory rate is the number of breaths per minute.

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

Stroke volume (SV) is the amount of blood ejected from the left ventricle per beat (mL/beat).

The phase of the cardiac cycle when the ventricles contract to pump blood into the arteries.