Anatomy of the heart
A normal heart is a powerful muscle pump. It can weigh between 200 and 425 grams (7-15 ounces) and its size is a little larger than your fist. Over a lifetime, the human heart will beat more than 2.5 billion times. Every day, an average heart beats about 100,000 times and pumps about 7,200 liters (1,900 gallons) of blood.
Your heart is located between your lungs in the middle of your chest, behind the breastbone, slightly left. A double membrane called the pericardium surrounds the heart like an envelope. Blood carrying oxygen reaches the lungs and into the heart. To function, the heart has to supply oxygen and nutrients it receives blood that is pumped in his coronary arteries.
Role
The circulatory system is comprised of the heart and the cardiovascular system. The heart pumps blood to the organs, tissues and cells in the body, delivering oxygen and nutrients to every cell of the body and remove carbon dioxide and waste products from the cells. Oxygen-rich blood is carried from the heart to the rest of the body through a complex network of arteries, arterioles and capillaries. The oxygen-poor blood returns to the heart through the veins.
Your heart is located between your lungs in the middle of your chest, behind the breastbone, slightly left. A double membrane called the pericardium surrounds the heart like an envelope. Blood carrying oxygen reaches the lungs and into the heart. To function, the heart has to supply oxygen and nutrients it receives blood that is pumped in his coronary arteries.
Role
The circulatory system is comprised of the heart and the cardiovascular system. The heart pumps blood to the organs, tissues and cells in the body, delivering oxygen and nutrients to every cell of the body and remove carbon dioxide and waste products from the cells. Oxygen-rich blood is carried from the heart to the rest of the body through a complex network of arteries, arterioles and capillaries. The oxygen-poor blood returns to the heart through the veins.
How does the heart work ?
The heart is a pump made up of four chambers. The upper chambers are called right atrium and left atrium. The lower chambers are called the right ventricle and left ventricle. A muscular wall called the septum separates the right and left atria and right and left ventricles.The left ventricle, the largest and most powerful of the chambers of the heart is able to pump blood throughout the body through the aortic valve.The two cavities of the right heart (right atrium and right ventricle) pump blood from the heart to the lungs so that blood cells can collect fresh oxygen in exchange of waste they collected during their visit in the body. The oxygen-rich blood returns to the left chambers of the heart (atrium and left ventricle), which then pump the rest of the body.When the heart muscle contracts, the two upper chambers (the atria) fill with blood. Then, these two chambers contract and expel blood into the ventricles. The ventricles then contract and push the blood out of the heart, or to the lungs or elsewhere in the body.
What happens during a heart beat?
In a normal heart, the electrical impulse that triggers the beat begins in a group of cells called the sinus node (or SA node) in the right atrium. The sinus node is often called heart rate regulator. It plays a role similar to that engine spark plugs of a car by producing the electrical signal that makes the heart pump. The sinus node generates a number of signals every minute, according to the needs of the organization. The resting heart rate is usually between 60 and 80 beats per minute.After an electrical pulse is produced, it spreads through the upper part of the heart (the atria), a bit like the ripples created by a stone thrown into a pond. This signal causes contraction of the upper chambers (atria). In contracting, they expel the blood contained therein to the lower chambers of the heart, the ventricles.Meanwhile, the electrical impulse that made the atria contract has now reached the atrioventricular node (AV node or) located in the lower part of the right atrium. The AV node is the electrical connection between the atria and the ventricles. It retains the electrical impulse for a while, a bit like a relay, so that blood can be pumped from the atria into the ventricles. Then, it sends the signal to the lower chambers of the heart, which in turn contract. The contraction of the ventricles pushes blood with great force. The electrical impulse has now passed through the upper and lower chambers of the heart and made them shrink. It's a heartbeat. This electrical activity produces measurable electrical pulses using a heart test called an electrocardiogram (ECG or EKG).
Anatomy of the heart
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