The body system that consists of the heart, blood vessels, and blood.
A hollow, muscular organ that pumps blood throughout the body.
Each of the two upper chambers of the heart that recieves blood that comes into the heart.
Each of the two lower chambers of the heart that pumps blood out of the heart.
A flap of tissue in the heart or a vein that prevents blood from flowing backward.
A group of cells located in the right atrium that sends out signals that make the heart muscle contract and that regulates heart rate.
A blood vessel that carries blood away from the heart
A tiny blood vessel where substances are exchanged between the blood and the body cells.
A blood vessel that carries blood back to the heart
The largest artery in the body that recieves blood from the left ventricle.