Glossary of Key Terms in Circulatory System

A set of vocabulary flashcards covering key terms from the circulatory system.

A type of white blood cell that lacks visible granules in its cytoplasm; includes lymphocytes and monocytes.

Agranulocyte

Tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs with the blood in capillaries.

Alveoli

A condition characterized by a deficiency of red blood cells or of hemoglobin in the blood, resulting in pallor and weariness.

Anemia

The main artery that carries oxygenated blood from the left ventricle of the heart to the rest of the body.

Aorta

A small branch of an artery leading into capillaries.

Arteriole

A blood vessel that carries blood away from the heart.

Artery

An upper chamber on each side of the heart that receives blood.

Atrium

A small mass of specialized cardiac muscle fibers at the base of the right atrium that receives the impulse from the SA node and transmits it to the ventricles after a slight delay.

Atrioventricular (AV) Node

The heart valve between the left atrium and the left ventricle.

Bicuspid Valve (Mitral Valve)

The pressure of blood in the circulatory system, closely related to the force and rate of the heartbeat and the diameter and elasticity of the arterial walls.

Blood Pressure

A small blood vessel connecting arterioles to venules, where the exchange of substances with the tissues occurs.

Capillary

A network of specialized muscle cells found in the walls of the heart that send electrical signals directly to the heart muscle.

Cardiac Conduction System

A blood test that measures different components of the blood, including red blood cells, white blood cells, and platelets.

Complete Blood Cell Count (CBC)

The circulation of blood in the blood vessels of the heart muscle (myocardium).

Coronary Circulation

The process during the action potential when the membrane potential of a cell becomes less negative, often leading to muscle contraction.

Depolarization

The phase of the heartbeat when the heart muscle relaxes and the chambers fill with blood.

Diastole

A recording of the electrical activity of the heart over a period of time, obtained by electrodes placed on the skin.

Electrocardiogram (EKG or ECG)

A red blood cell, which contains hemoglobin and transports oxygen.

Erythrocyte

An insoluble protein formed from fibrinogen by the action of thrombin, which forms the framework of a blood clot.

Fibrin

A soluble protein in blood plasma that, when acted upon by thrombin, forms fibrin.

Fibrinogen

A type of white blood cell that contains visible granules in its cytoplasm; includes neutrophils, eosinophils, and basophils.

Granulocyte

The number of times the heart beats per minute.

Heart Rate

The ratio of the volume of red blood cells to the total volume of blood.

Hematocrit

The iron-containing oxygen-transport protein in red blood cells.

Hemoglobin

A specialized counting chamber used to determine the number of cells in a blood sample.

Hemocytometer

The process of stopping blood loss.

Hemostasis

Specialized cardiac muscle fibers that conduct electrical impulses from the AV bundle to the ventricles.

His-Purkinje System