Grade 11 biology - the circulatory system

Hemolymph

A mixture of blood and tissue fluid that is the circulating fluid in an open circulatory system

Atrium

A chamber of the heart that received blood from the body

Ventricle

A chamber of the heart that pumps blood to the body

Septum

A wall of tissue that divides a body cavity or structure into smaller parts; for example, the ventricle of a mammal’s heart is divided into two cavities by a septum

Pulmonary circuit

The part of the circulatory system that delivers blood to the lungs

Systemic circuit

The part if the circulatory system they delivers blood around the body

Serum

The fluid that results when the cells, platelets and fibrinogen have been removed from whole blood

Leukocyte

A white blood cell

Pus

A yellowish-white fluid formed in infected tissue, consisting of white blood cells and cellular debris

Platelet

A cell fragment in the blood that is necessary for blood clotting

Erythrocyte

A red blood cell

Aorta

The largest blood vessel in the body, connected directly to the heart; the aorta branches into arteries that carry oxygenated blood to the body tissues

Arteriole

The smallest artery, with smooth muscle in its walls

Vasodilation

An increase in the diameter (dilation) of arterioles that increases the blood flow to tissues

Vasoconstriction

A disease in the diameter of arterioles that decreases the blood flow to tissue

Venule

The smallest vein; formed by the merging of capillaries

Systolic pressure

The blood pressure in the arteries when the heart contracts

Thymus

A glandular organ of the lymphatic system; secretes hormones to promote the maturity of lymphocytes

Pericardium

A two layered fluid-filled membrane that surrounds the heart and prevents friction between the heart and other tissues and organs

Coronary blood vessel

A blood vessel that circuits blood to and from the muscle cells of the heart

Semilunar valve

The valve located between the left ventricle and the aorta and the right ventricle and the pulmonary arteries to prevent the back flow of blood when the ventricles relax

Atrioventricular valve

The valve located between each atrium and ventricle to prevent the back flow of blood from the ventricles to the atria

Chordae tendineae

Tendons that support the atrioventricular valves

Cardiac cycle

The contractions and relaxations of the heart muscles during a complete heartbeat

Diastole

The period of the cardiac cycle when the ventricles are relaxed; blood fills the ventricles

Systole

The period of the cardiac cycle when the ventricles contract; blood is ejected from the ventricles

Myogenic muscle

muscle that can contract and relax without input from an external source

Sinoatrial (SA) mode

A mass of muscle and nerve cells in the right atrium; initiates the heartbeat and maintains the regular rythem

Atrioventricular (AV) node

A mass of conducting cells that transmits the signals from the SA node to the muscles of the ventricles

Purkinje fibre

A conducting fibre that carries the electrical signals from the AV node to the muscle cells of the ventricles

Electrocardiograph

A device that detects the electrical activity of the heart through electrodes placed on the body’s surface

Angina

Pain in the chest, left shoulder, arm, or neck caused by insufficient blood supply to the cardiac muscles

Arteriosclerosis

The loss of elasticity and hardening of the arteries that may be caused by a number of factors including hypertension, age and plaque buildup

Plaque

Deposits of fat, cholesterol, calcium and other materials on and in the walls of arteries

Atherosclerosis

The hardening of the arteries due to the buildup of plaque on or inside the walls of the arteries; atherosclerosis is the most common form of atheriosclerosis

Coronary artery disease (CAD)

The buildup of plaque on or inside the walls of the coronary arteries

Myocardial infarction

The death of cardiac muscle tissue due to oxygen deprivation; also known was a heart attack

Angioplasty

A medical procedure that opens up a blocked artery; it is often used to enlarge narrowed opening in coronary arteries

Bypass surgery

A surgical procedure in which arteries are grafted to blocked (or narrowed) coronary arteries in order to reroute blood

Cardiac catheterizartion

The insertion of a long thin tube called a catheter into the heart through an artery, usually that femoral or brachial artery

Angiogram

An X-ray image showing the outline of blood vessels through the use of an injected dye

Computerized tomography (CT) scan

An X-ray imaging technology that produces cross-sectional images of a three-dimensional object

Positron emission tomography (PET) scan

An imaging technology that produces cross-sectional images from gamma rays emitted by a radioactive tracer injected into body tissues

Magnetic resonance imaging (MRI) scan

An imaging technology that produces images by using a magnetic field to change the orientation of hydrogen atoms in tissues