What is the Heart and How it Works

The normal heart is a strong muscle that acts as a continuous ejection pump. Its function is to eject the blood into the circulatory system. The normal heart of a person 25 weighs about 300 grams, circulates 5.5 liters per minute and achieves more than 100 000 beats per day. The circulatory system is a network of elastic tubes that allow blood to flow inside our body. It is formed by the heart, lungs, arteries and capillaries of different sizes (microscopic blood vessels). These blood vessels carry oxygen and nutrients from the blood to all parts of our body. This system also includes veins of different sizes that lead back the blood has cleared of oxygen and nutrients back to the heart and then to the lungs (like a drain). This network is so extensive that it would make two laps around the earth. The circulation of blood brings oxygen and nutrients to all cells, tissues and organs including the heart itself, as well as collects the debris of those cells that are filtered in the kidneys, liver and lungs. The operation of the heart as a pump The heart pumps blood to the lungs and other organs of our body because of a well-organized sequence of contractions of the four chambers. This sequence is controlled by an electrical stimulus that moves through the muscles by a nervous pathway. This stimulus comes in a set of specialized cells located in the right atrium (sinus node) and follows a nerve pathway that subsequently bifurcates into two branches right and left. The electrical discharge that natural pacemaker, leads to the sequential contraction of heart muscle in a natural frequency but emotional reactions and hormonal factors can affect the frequency of discharges. This allows our heart adapts and responds to the varying flow demands. The structure of the Heart The muscle infarction is the way the heart walls. Its contraction leads to ejection of blood through the vessels and relaxation facilitates filling again. Their outer surface is called the epicardium and its inner side with the endocardium. The heart is composed of four chambers in which the blood flows and is pumped. The upper chambers form the right and left atria and form the lower right and left ventricles. There are four valves that open and close in a harmonic way, causing the blood to flow in one direction every time there is a contraction of the heart muscle. These valves will s: - The tricuspid valve, located between the right atrium and right ventriclern- The pulmonary valve between the right ventricle and pulmonary arteryrn- The mitral valve between the left atrium and left ventriclern- The aortic valve, between the left ventricle and the aorta. Each valve is formed by leaflets called leaflets. The mitral valve has two leaflets, the other three. Under normal conditions, these valves allow blood flow in one direction. This flow occurs only when there is a difference in pressure between the valve and will be the reason for opening and closing them. The circulatory system The circulation system is formed by the heart and blood vessels. The heart pumps oxygen-rich blood through the arteries to all of our body. The veins are the vessels respons ables the drain back to the heart. Arteries and veins are connected by fine-called capillary vessels. This is called the circulatory system. The right chambers of the heart receive blood purged of oxygen through the superior and inferior vena cava. This blood is sent to the lungs where gas exchange occurs which removes carbon dioxide and the enriched with oxygen again. This new blood returns to the left chambers of the heart via the pulmonary veins and is again pumped through the aorta to nourish our body orgões. Collateral circulation Collateral circulation is a process in which small arteries, normally closed, open and connecting large vessels or certain classes of them. This serves as an alternative to the restricted blood supply. All people have this collateral circulation, at least at the microscopic level but are more developed or expanded in people with heart and vascular diseases. The presence of these vessels is a natural alternative to solve the lack of oxygen in certain tissues but not always the most efficient Needs aria.