C IRCULATORY S YSTEM

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C IRCULATORY S YSTEM Often called the cardiovascular system Consists of the heart, blood vessels, and blood

F UNCTIONS Carries needed substances to cells such as glucose and oxygen. Carries unwanted waste away from cells Contains cells in blood that fight disease

T HE H EART Hollow organ made of cardiac muscle 2 upper chambers are called atria that receive blood. 2 lower chambers are called ventricles that pump blood

H OW THE H EART W ORKS Two phases 1. Heart muscle relaxes and fills with blood 2. Heart muscle contracts and pumps blood forward “Lub-dup”- sound of your heartbeat as valves close when heart is pumped

K INDS OF B LOOD V ESSELS Arteries- carries blood away from the heart Veins-carries blood to the heart Capillaries-tiny vessels that exchange substances between blood and body cells (usually by diffusion)

P ULSE VS. B LOOD P RESSURE expansion and contraction of arteries determines number of heartbeats. force of blood caused by ventricles contracting measured with a sphygmomanometer PulseBlood pressure

P ATHWAY OF B LOOD Loop One- “Picking up oxygen” Oxygen poor blood: Heart>lungs>heart Loop Two- “Dropping off Oxygen” Oxygen rich blood: Heart>body>heart

C ARDIOVASCULAR D ISEASE Atherosclerosis- occurs when fatty materials such as cholesterol build up in the arteries possibly leading to a heart attack. Hypertension- occurs when blood pressure is too high causing the heart to work harder.

M AINTAINING C ARDIOVASCULAR H EALTH Exercise regularly Eat balanced diet low in saturated and trans fats, cholesterol and sodium Reduce stress Avoid smoking.