Exchange substances official content key terms

Cardiac output

The volume of blood pumped by the heart per minute, calculated as heart rate multiplied by stroke volume.

Stroke volume

The amount of blood ejected by the left ventricle during each contraction.

Artery

A blood vessel that carries oxygenated blood away from the heart.

Capillary

The smallest blood vessel, where gas and nutrient exchange occurs.

Mass transport

The movement of substances within an organism, typically through a specialized system such as the circulatory system in animals.

Alveoli

Tiny air sacs in the lungs where gas exchange occurs, characterized by a large surface area and thin walls.

Xylem

A type of vascular tissue in plants responsible for the transport of water and minerals from the roots to the leaves.

Transpiration

The process of water vapor loss from the aerial parts of plants, primarily through stomata.

Cohesion

The attraction between water molecules due to hydrogen bonding, which helps maintain a continuous water column in plants.

Tension

The negative pressure created in the xylem as water evaporates from the leaf surface, aiding in the upward movement of water.

Translocation

The movement of organic compounds, particularly sugars, from sources to sinks in plants via the phloem.

Phloem

A type of vascular tissue in plants responsible for the transport of nutrients and sugars produced by photosynthesis.

Transpiration

The process of water vapor loss from plant leaves through stomata.

Pressure gradient

A difference in pressure that drives the movement of fluids in plants.

Transpiration

The process of water vapor loss from plant surfaces, primarily through stomata.

Xylem

The vascular tissue in plants responsible for the transport of water and minerals from the roots to the leaves.