Cardiovascular System Key Terms 7 th Grade Science

Cardiovascular System The body system that consists of the heart blood vessels and blood that carries needed substances to cells and carries waste products away from cells

Heart A hollow muscular organ that pumps blood throughout the body

Atrium Each of the two upper chambers of the heart that receives blood entering the heart

Ventricle A lower chamber of the heart that pumps blood out to the lungs and body

Valve A flap of tissue in the heart or a vein that prevents blood from flowing backwards

Pacemaker A group of cells located in the right atrium that send out signals that make the heart muscle contract and that regulates heart rate

Artery A blood vessel that carries blood away from the heart

Capillary A tiny blood vessel where substances are exchanged between the blood and body cells

Vein A blood vessel that carries blood back to the heart

Aorta The largest artery in the body

Coronary artery An artery that supplies blood to the heart

Blood pressure The pressure the is exerted by the blood against the walls of blood vessels

Diffusion The process by which molecules move from an area in which they are more concentrated to an area in which they are less concentrated

Plasma The liquid part of the blood

Red blood cells A cell in the blood that takes up oxygen in the lungs and delivers it to cells elsewhere in the body

Hemoglobin An iron containing protein that binds chemically to oxygen molecules and makes up most of a red blood cells

White blood cell A blood cell that fights disease

Platelet A cell fragment that plays an important part in forming clouts

Arteriosclerosis A condition in which an artery wall thickens as a result of a build up of fatty materials

Heart attack A condition in which blood flows to a part of the heart; the heart muscle is blocked which causes heart cells to die

Hypertension A disorder in which a person’s blood pressure is constantly higher than normal