Which node triggers the contraction of the atrium?

The chambers of the heart expand or dilate during which phase of the cardiac cycle?

Which valves close when the ventricular systole begins?

The chamber of the heart that receives oxygen-deficient blood from the body is the

Identify the vessels that transport oxygenated blood from the lung to the left atrium.

The aorta begins at the

The ______ of the heart is said to be the beginning of the pulmonary circulation, and the _______ of the heart is the end of pulmonary circulation.

Which valves open when the ventricular diastole begins?

Identify the circuit that pumps blood from the heart to the lungs, and back to the heart.

The tricuspid valve is located between the