The Circulatory System Cambridge (CIE) AS Biology Flashcards

A set of vocabulary flashcards covering the systems, vessels, and components of the human circulatory system based on the CIE AS Biology curriculum.

Mass transport

The bulk movement of gases or liquids in one direction, usually via a system of vessels and tubes.

Open circulatory system

A system where blood is not contained within blood vessels but is pumped directly into body cavities, found in organisms such as arthropods and molluscs.

Closed circulatory system

A system where blood is pumped around the body and is always contained within a network of blood vessels, characteristic of all vertebrates.

Closed double circulatory system

In one complete circuit of the body, blood passes through the heart twice; a system where exchange surfaces are connected to a mass transport system.

Pulmonary circulatory system

The part of the circulatory system that pumps deoxygenated blood from the right side of the heart to the lungs for gas exchange.

Systemic circulatory system

The part of the circulatory system that pumps oxygenated blood from the left side of the heart at high pressure around the body.

Heart

A hollow, muscular organ located in the chest cavity which pumps blood, made of specialised cardiac muscle tissue for repeated involuntary contraction.

Arteries

Blood vessels that carry blood away from the heart at high pressures, featuring walls with muscle, elastic tissue, and a narrow lumen.

Arterioles

Small arteries that branch from larger arteries and connect to capillaries; they have lower blood pressure than arteries.

Capillaries

Tiny blood vessels that connect arterioles and venules, with walls only one-cell thick to allow substances like glucose and oxygen to diffuse easily.

Venules

Small veins that join capillaries to larger veins.

Veins

Blood vessels that carry blood back towards the heart under low pressure, characterized by thin walls, a wide lumen, and one-way valves.

Elastic artery

Arteries closer to the heart with a higher proportion of elastic fibres in a thinner tunica media, allowing them to stretch and recoil to accommodate blood surges.

Muscular artery

Arteries further from the heart with a thicker tunica media composed mainly of smooth muscle, capable of performing vasoconstriction and vasodilation.

Red blood cells

Specialised cells containing haemoglobin that transport oxygen; they have a distinctive biconcave disc shape and lack a nucleus.

Haemoglobin

A protein with a quaternary structure containing haem iron groups that bind reversibly to oxygen.

Monocyte

The largest type of leukocyte (white blood cell), identified by a nucleus shaped like a kidney or a bean that appears light blue after staining.

Neutrophils

White blood cells that make up to 70% of all leukocytes, identifiable by their multi-lobed nuclei and granules that stain pink or purple-blue.

Lymphocytes

Small leukocytes, approximately the size of red blood cells, identifiable by very large nuclei that typically stain a dark colour.

Specific heat capacity of water

The energy required to raise the temperature of $1\,kg$ of water by $1^{\circ}C$, which is $4200\,J/Kg^{\circ}C$.

Plasma

A straw-coloured liquid that constitutes around $55\%$ of the blood and is composed of $95\%$ water, serving as a solvent for transporting substances.

Tissue fluid

Fluid formed when plasma leaks through gaps in capillary walls to surround body cells, virtually the same as plasma but without large proteins.

Hydrostatic pressure

The blood pressure exerted by the blood on the walls of the blood vessels, which pushes molecules out of the capillary at the arterial end.

Solute concentration gradient

A gradient caused by proteins dissolved in the blood that lower water potential, drawing water back into capillaries from tissues by osmosis.