Circulatory system - The Heart

• The circulatory system carries food and oxygen to every cell in your body; it can also carry waste products to where they can be removed from the body.
• The heart is a double circulatory system because the right ventricle pumps deoxygenated blood to the lungs and then returns to the heart. At the same time the left ventricle pumps oxygentaed blood to the rest of the body and the deoxygenated blood returns to the heart.
• The heart is a pumping organ that's goal is to keep blood pumping around the body.
• What are the walls of the heart made out of?


  Muscle tissue.
• Why does the heart have valves?


  To prevent the backflow of blood.
• What are the hearts four chambers?

  Right atrium, left atrium, right ventricle and left ventricle.
• Blood flows into the two atris from the vena cave to the pulmonary vein. The atria contracts, pushing blood in the ventricles. The ventricles then contract, forcing the blood into the pulmonary artery and aorta, and out of the heart. The blood then flows to the organs thrugh the arteries and returns to the veins.
• the heart needs its own supple od oxygenated blood. Arteries called coronary arteries branch off the aorta and surround the heart, makung sure it gets all the oxygentated blood it needs.
• The resting heart rate is conrolled by a group of calls in the right atrium wall that act as a pacemaker. These cells produce an electric impulse which spreads to the surrounding muscle cells, causing them to contract.
• What is an artificial pacemaker's purpose?


  Used to control heartbeat if the netural pacemaker cells don't work properly. It's a little device that's implanted under the skin and has a wire going to the heart. it produces an electric current to keep the heart beating regularly.
• The heart is a double circulatory system because the right ventricle pumps deoxygenated blood to the lungs and then returns to the heart. At the same time the left ventricle pumps oxygentaed blood to the rest of the body and the deoxygenated blood returns to the heart.