A flap-like structure in the heart which controls the one-way passage of blood through the organ.
A vessel which conveys blood back to the heart. It generally carries deoxygenated blood, except for the pulmonary vein in humans which transports oxygen-rich blood from the lungs back to the left side of the heart.
Either of two large veins conveying deoxygenated blood to the heart. The superior vena cava carries blood from the upper part of the body (i.e. from the head, neck, and chest area upward of the fifth lumbar vertebra), while the inferior vena cava carries blood from the lower part of the body (i.e. downward from the fifth lumbar vertebra).
The two lower chambers of the heart which hold blood to be pumped out of the heart. The right ventricle contains deoxygenated blood which is to be transported via the pulmonary arteries to the lungs. The left ventricle, in contrast, holds oxygenated blood to be distributed to other parts of the body via the aorta.
A potentially fatal form of ventricular tachycardia in which the ventricles flutter so rapidly that they hardly pump any blood.
A congenital heart defect in the form of a hole between the two ventricles.
An abnormally fast heart rate, usually of more than 120 beats per minute, which arises due to the ventricles beating too rapidly.