1.1 the heart

• circulatory system or cardiovascular system: the system consisting of the heart, blood vessels, and blood that circulated through the body
• cardiac output: the volume of blood pumped by the heart in one minute, which is equal to the product of stroke volume and heart rate
• septum: a thick wall of muscle that divides the left and right sides of the heart
• atrium: the smaller upper chamber that receives blood returning to the heart
• ventricle: the larger v-shaped bottom chamber that pumps blood from the heart
• heart valves: thin flaps of tissue in the heart that open and close to ensure proper direction for blood flow
• diastole: the phase of the heart's cycle where a chamber of the heart, either an atrium or a ventricle, relaxes and fills with blood
• systole: the phase of the heart's cycle when the ventricles contract to eject blood from within the chamber