What powers the human heart?
106639
electric pulses. everything in our body is controled by electricity. thats why you can start or stop a heart with electronic shock.
348835
Humans have a closed circulatory system.  It is when the blood is contain in the veins and arteries.  Where the arteries take blood to the body and the veins take it directly back.  In an open system the heart pumps blood out into an open area where the blood just flows over the different body parts and then comes back to the heart on its own.  An open circulatory system is extremely inefficient and a lower form of evolution.
560165
mainly, the heart pumps blood forward, but can be aided by the action of the muscles--they help keep blood and lymph flowing.  Additonailly, the veins have one way valves so that once the blood goes through a valve, it can't go backwards while the heart is relaxing.
116068
Does your heart stop when you sneeze?\n– Lauren K, El Cajon\n\nNo. The heart's rhythm is controlled by a natural pacemaker – the sinoatrial node, a group of cells located in the right atrium of the heart. These cells create an electrical impulse by pumping charged particles out of the cell and then allowing them to flow back in. Conducting cells transmit the electrical impulse to all parts of the heart to initiate muscle contraction. Sneezing does not stop this electrical activity.\n\nHowever, the nervous system and circulating hormones, such as adrenaline, alter the rate of the electrical activity in the sinoatrial node to increase or decrease heart rate. Just as exercise leads to an increased heart rate, sneezing works many muscles; therefore it is possible for a "sneeze attack" to increase heart rate.\n--------------------\nSherry Seethaler has a doctorate in science education and is a UCSD science writer and educator. Send your scientific questions to her at Quest, San Diego Union-Tribune, P.O. Box 120191, San Diego, CA 92112-0191. Or e-mail sseethaler@ucsd.edu. Please include your name, city of residence and phone number.\n======================================\nDear Earl,\nWhen I sneeze, does my heart stop?\n\nBen, Age 12\n\nDear Ben,\nDefinitely not, although that is a common myth. Looking at the sites in our Heart category, your heart keeps pumping blood throughout your body from when you're a baby in your mother's womb until the moment of death. Your heart beats all day and all night, all the time. When you run or play hard, your heart beats faster. When you're asleep, your heart beats slower, but it doesn't stop. If a person needs heart surgery, doctors hook the patient up to a machine that pumps blood for the heart. Only then is it safe for the doctor to stop the heart in order to operate. When you sneeze, the muscles in your abdomen, chest, and throat are all involved. And, even though you might not notice it, your heart is working too.\n\nEarl
632354
I think it's protein. Because most of the human organ need protein to be form. The human organ, including heart are consist of cells, and they need protein to regenerate, I think this also happens when they were formed in fetus period.
977329
Gravity!  the heart works harder to pump blood when you are standing!
606273
I know much about the heart. It's one of the most important organs in your body. (probably the most important if you want to stay alive). It is a very complicated system.\n\nYour question is too broad, I don't understand what you're trying to ask. Your question is more of an opinion one. If you have a particular question, I'd would be glad to answer.
16348
The heart is a double pump with four chambers, each separated by valves that only permit blood to flow in one direction. Basically, the right side of the heart pumps deoxygenated blood to the lungs, while the left side pumps oxygenated blood to the body.
807200
The first link has an animated description.Anatomy of the Human Heart with Flash Illustration\n\n    *  The Right Atrium, receives "used blood" from the body. Blood will be pushed through the tricuspid valve to the\n\n    * Right Ventricle, the chamber which will pump to the lungs through the pulmonic valve to the\n\n    * Pulmonary Arteries, providing blood to both lungs. Blood is circulated through the lungs where carbon dioxide is removed and oxygen added. It returns through the\n\n    * Pulmonary Veins, which empty into the\n\n    * Left Atrium, a chamber which will push the Mitral Valve open. Blood then passes into the\n\n    * Left Ventricle. Although it doesn't always look like it in drawings done from this angle, this is the largest and most important chamber in the heart. It pumps to the rest of the body. As it pumps, the pressure will close the mitral valve and open the aortic valve, with blood passing through to the\n\n    * Aorta, where it will be delivered to the rest of the body.\n\n\nhttp://www.heartpoint.com/theheart.html\n\nhttp://www.pbs.org/wgbh/nova/heart/\n\nhttp://texasheart.org/HIC/Anatomy/Anatomy.cfm\n\nhttp://education.yahoo.com/reference/gray/illustrations/figure?id=505\n\nhttp://sln2.fi.edu/biosci/preview/heartsee.html\n\nhttp://www.geocities.com/Athens/Forum/6100/1heart.html\n\nSTRUCTURE OF THE HEART.\n\nhttp://www.infovisual.info/03/062_en.html\n\nhttp://www.cayuga-cc.edu/people/facultypages/greer/biol204/heart1/heart1.html\n\nhttp://www.geocities.com/Athens/Forum/6100/1HrtPics.html\n\nGood luck.\n\nKevin, Liverpool, England.
861263
It stops the heart from beating.
97736
overall system that's working with the heart. Cardio - heart, vascular- blood vessels.
475089
cardiac muscle or myocardium
581377
a more efficient heart
241545
cardiovasular system, pumps the blood for circulation.
8699
blood pressure, force exerted by the blood upon the walls of the arteries. The pressure in the arteries originates in the pumping action of the heart, and pressure waves can be felt at the wrist and at other points where arteries lie near the surface of the body (see pulse). Since the heart can pump blood into the large arteries more quickly than it can be absorbed and released by the tiny arterioles and capillaries, considerable inner pressure always exists in the arteries. The contraction of the heart (systole) causes the blood pressure to rise to its highest point, and relaxation of the heart (diastole) brings the pressure down to its lowest point.\nBlood pressure is strongest in the aorta, where the blood leaves the heart. It diminishes progressively in the smaller blood vessels and reaches its lowest point in the veins (see circulatory system). Blood pressure manifests itself dramatically when an artery is severed or pierced and the blood (under pressure) ejects in spurts.
1003119
look at this 3D pic then read\n\nhttp://library.thinkquest.org/C003758/rotate.htm\n\nIn the human body, the heart is normally situated slightly to the left of the middle of the thorax, underneath the sternum (breastbone). The heart is usually felt to be on the left side because the left heart (the left part of the heart) is stronger (it pumps the blood out). The heart is enclosed by a sac known as the pericardium and is surrounded by the lungs.Betwen the pericardium and the heart there is a serous fluid to reduce friction during heart contractions. The apex is the blunt point at the base of the heart. A stethoscope can be placed directly over the apex and count the beats. In normal adults, its mass is 250-350 g (8-11 oz), but extremely diseased hearts can be up to 1000 g (2 lb) in mass. It consists of four chambers, the two upper atria (singular: atrium ) and the two lower ventricles. On the right is a picture of a fresh human heart which was just removed from a 64 year old British gentleman. The mass for a thin white male is usually 270-300 grams (9-11 ounces) with little fat.\n\nA septum divides the right atrium and ventricle from the left atrium and ventricle, preventing blood from passing between them. Valves between the atria and ventricles (atrioventricular valves) maintain coordinated unidirectional flow of blood from the atria to the ventricles. The ventricular systole consists of the contraction of the ventricles and flow of blood into the circulatory system. Again, once all the blood empties from the ventricles, the pulmonary and aortic semilunar valves close. Finally complete cardiac diastole involves relaxation of the atria and ventricles in preparation for refilling with circulating blood.\n\nThe function of the right side of the heart (see right heart) is to collect deoxygenated blood from the body and pump it into the lungs (pulmonary circulation)so that carbon dioxide can be dropped off and oxygen picked up. This happens through a process called diffusion. The left side (see left heart) collects oxygenated blood from the lungs and pumps it out to the body (systemic circulation). On both sides, the lower ventricles are thicker than the upper atria.\nOxygen-depleted or deoxygenated blood from the body enters the right atrium through two great veins, the superior vena cava which drains the upper part of the body and the inferior vena cava that drains the lower part which drains the portal cyrculation too full with nutrients to nourish the body. The blood then passes through the tricuspid valve to the right ventricle. The right ventricle pumps the deoxygenated blood to the lungs, through the pulmonary artery. In the lungs gaseous exchange takes places and the blood releases carbon dioxide into the lung cavity and picks up oxygen which is called external respiration. The oxygenated blood then flows through pulmonary veins to the left atrium. From the left atrium this newly oxygenated blood passes through the mitral valve (also called the bicuspid valve) to enter the left ventricle. The left ventricle then pumps the blood through the aorta to the entire body. Even the lungs take some of the blood supply from the aorta via bronchial arteries.\n\nThe left ventricle is much more muscular, which is 1.3 - 1.5 cm (.5-.6 in) thick, than the right, 0.3 - 0.5 cm ( .1-.2 in) thick, as it has to pump blood around the entire body, which involves exerting a considerable force to overcome the vascular pressure. As the right ventricle needs to pump blood only to the lungs, it requires less muscle.\n\nEven though the ventricles lie below the atria, the two vessels through which the blood exits the heart (the pulmonary artery and the aorta) leave the heart at its top side.\n\nThe contractile nature of the heart is due to the presence of cardiac muscle in its wall which can work continuously without fatigue. The heart wall is made of three distinct layers. The first is the outer epicardium which is composed of a layer of flattened epi
190743
The energy for the mechanical heart. Also mechanical hearts tend to create a lot of blood clots, so people that use these usually die of strokes.