Heart
Atria - the upper chambers of the heart. They receive blood returning to your heart from
either the body or the lungs. The right atrium receives deoxygenated blood from the superior
and inferior vena cava. The left atrium receives oxygenated blood from the left and right
pulmonary veins.
Ventricles - The pumping chambers of the heart. They have thicker walls than the atria. The
right ventricle pumps blood to the pulmonary circulation for the lungs and the left ventricle
pumps blood to the systemic circulation for the body.
Bicuspid valve - One of the four valves in the heart, situated between the left atrium and the
left ventricle. It allows the blood to flow in one direction only, from the left atrium to the left
ventricle.
Tricuspid valve - Situated between the right atrium and the right ventricle, it allows blood to
flow from the right atrium to the right ventricle.
Aortic valve - situated between the left ventricle and the aorta, prevents backflow from the
aorta into the left ventricle.
Pulmonary valve - Between the right ventricle and the pulmonary artery, prevents backflow
from the pulmonary artery.
Aorta - The body’s main artery. It originates in the left ventricle and carries oxygenated
blood to all parts of the body.
Superior vena cava - A vein that receives deoxygenated blood from the upper body to
empty into the right atrium of the heart.
Inferior vena cava - A vein that receives deoxygenated blood from the lower body to empty
into the right atrium of the heart.
Pulmonary vein - Carries oxygenated blood from the lungs to the left atrium of the heart.
Pulmonary artery - Carries deoxygenated blood from the heart to the lungs. It is the only
artery that carries deoxygenated blood.
Blood vessels
As the heart contracts, blood flows around the body in a complex network of vessels. The
structure of arteries, veins and capillaries are all different as they are determined by their
different functions and the pressure of blood within them. Blood flowing through the arteries
appears bright red, due to its oxygenation. As it moves through the capillaries it drops off
oxygen and picks up carbon dioxide. By the time it reaches the veins it is much lower.
Arteries - Arteries carry blood away from the heart. They have two major properties:
elasticity and contractility. They have thick muscular walls to carry blood at high speeds
under high pressure. When the heart ejects blood into the large arteries, the arteries
vasodilate to accommodate the extra blood. The smooth muscle surrounding the arteries
enables their diameter to be decreased and increased as required. This helps maintain
blood pressure in relation to changes in blood flow.
Capillaries - Capillaries form an extensive network that connects arteries and veins by
uniting arterioles and venules.They are the smallest of all blood vessels, narrow and very
thin. They form an essential part of the vascular system as they bathe the tissues of the
Atria - the upper chambers of the heart. They receive blood returning to your heart from
either the body or the lungs. The right atrium receives deoxygenated blood from the superior
and inferior vena cava. The left atrium receives oxygenated blood from the left and right
pulmonary veins.
Ventricles - The pumping chambers of the heart. They have thicker walls than the atria. The
right ventricle pumps blood to the pulmonary circulation for the lungs and the left ventricle
pumps blood to the systemic circulation for the body.
Bicuspid valve - One of the four valves in the heart, situated between the left atrium and the
left ventricle. It allows the blood to flow in one direction only, from the left atrium to the left
ventricle.
Tricuspid valve - Situated between the right atrium and the right ventricle, it allows blood to
flow from the right atrium to the right ventricle.
Aortic valve - situated between the left ventricle and the aorta, prevents backflow from the
aorta into the left ventricle.
Pulmonary valve - Between the right ventricle and the pulmonary artery, prevents backflow
from the pulmonary artery.
Aorta - The body’s main artery. It originates in the left ventricle and carries oxygenated
blood to all parts of the body.
Superior vena cava - A vein that receives deoxygenated blood from the upper body to
empty into the right atrium of the heart.
Inferior vena cava - A vein that receives deoxygenated blood from the lower body to empty
into the right atrium of the heart.
Pulmonary vein - Carries oxygenated blood from the lungs to the left atrium of the heart.
Pulmonary artery - Carries deoxygenated blood from the heart to the lungs. It is the only
artery that carries deoxygenated blood.
Blood vessels
As the heart contracts, blood flows around the body in a complex network of vessels. The
structure of arteries, veins and capillaries are all different as they are determined by their
different functions and the pressure of blood within them. Blood flowing through the arteries
appears bright red, due to its oxygenation. As it moves through the capillaries it drops off
oxygen and picks up carbon dioxide. By the time it reaches the veins it is much lower.
Arteries - Arteries carry blood away from the heart. They have two major properties:
elasticity and contractility. They have thick muscular walls to carry blood at high speeds
under high pressure. When the heart ejects blood into the large arteries, the arteries
vasodilate to accommodate the extra blood. The smooth muscle surrounding the arteries
enables their diameter to be decreased and increased as required. This helps maintain
blood pressure in relation to changes in blood flow.
Capillaries - Capillaries form an extensive network that connects arteries and veins by
uniting arterioles and venules.They are the smallest of all blood vessels, narrow and very
thin. They form an essential part of the vascular system as they bathe the tissues of the
