APPAREIL_CIRCULATOIRE

Important: The translations are performed by google. Thank you to forgive the shortcomings that still will understand much of the content of the page. Thank you for your understanding.

The site contains about 1000 pages! Each of them will be translated, which requires a lot of patience and understanding. Thank you very much.

Circulation has a duty to carry blood to the body, to promote the exchange of substances, heat and hormonal regulation. The engine traffic is the HEART is a hollow muscle, see the photo of the inside of the heart:

By contraction, blood is expelled by the heart in the distribution system consists of arteries and veins. Each heartbeat cycle is divided into two phases of contraction or: systole, and those of rest or: diastole. For a heart frequency of 70 pulsations minutes, the heart performs on average 100'000 cycles (systole / diastole) per day! Summary of phases of contraction of the heart:

DIASTOLIC: two small chambers of the heart, the AURICLES, fill with blood. The right atrium is responsible for deoxygenated blood blue color, while the left atrium is responsible for red oxygenated blood.

SYSTOLE: the muscular walls of the two atria contract up and down, driving their blood contained in VENTRICLES. Under the effect of this contraction, blood from the right atrium causes the opening of the tricuspid valve to step into the right ventricle. Under the same pressure effect, the blood of the left atrium crosses the VALVE MITRAL to enter the left ventricle ..

It is then the turn of the ventricles to contract from the bottom, thus driving up the blood. The blood pressure of the right ventricle, crossed the PULMONARY VALVE and into the pulmonary artery to go take care of oxygen in the lungs. Simultaneously, the oxygenated blood from the left ventricle into the aorta is removed after passing the pressure AORTIC VALVE.

Then the pulmonary valve and the aortic up tight to prevent blood from flowing back into the ventricles. The entire heart muscle relaxes to a new resting phase, and another cycle begins: right atrium fills led by VEINS CAVES blood, and the left ear fills led by PULMONARY VEINS blood.

All tissues need to be watered constantly. The blood distributes their nutrients and oxygen, and get rid of their waste. If any part of the body is deprived of this irrigation, only a few minutes, it may be seriously damaged, and even die. Blood constantly travel the same loop that always returns to its starting point two complementary paths: the SMALL and LARGE CIRCULATION. In the small circulation, blood will be oxygenated in the lungs and returns to the heart, which circulates in the rest of the body in the systemic circulation, that is to say, the irrigation of the body.

5 = Artery and Vein Deputy Clavires * 6 = Axillary artery and vein * 7 = Pulmonary pedicle * 8 = circumflexes Vaisseaux * 34 = Superior Vena Cave * 35 = Arch of the aorta * 36 = Pulmonary Artery * 37 = Pulmonary veins

The blood is circulated through the arteries to CAPILLARIES tissue before being reassembled at the heart through the veins:

To contain the pressures imposed, arteries and veins are composed of a blend of fabrics, each with a specific function:

Veins and arteries have a similar structure. They all have an inner lining of flattened cells: EPITHELIUM. Around it is the INNER TUNIC, consisting of connective tissue and elastic fibers covered by TUNIQUE MEDIAN, composed of smooth muscle. The whole is surrounded by the OUTER TUNIC, fibrous consistency.

The essential difference between veins and arteries, is that they have a thicker central tunic, able to withstand the high pressures to which they are subject. Given the low pressure in the veins, they are equipped with VALVES that stop blood, preventing back:

By their contraction, the muscles surrounding the blood vein hunt up. It passes through the upper valve open, while the lower valve acts as a check valve. A vein released, snaking under the skin, is a varicose vein. Varicose veins are mainly due to damaged valves or a hereditary weakness of the vein walls. Stagnation of blood, is compounded by a standing posture, lack of exercise or excessive weight. Following the enlargement of the veins and slowing the flow of blood can form clots or THROMBUS. If these clots break off, they enter the circulatory system, to arrive lungs occurs PULMONARY EMBOLISM. These clots in the heart, causing MYOCARDIAL!

Check the heart, especially after 50 years, is paramount. Here for example, the pictures of the exam I asked after a SCINTIGRAPHY

The scintigraphy is a series of pictures carving heart slices (Photo A), identical to the scanner, which can detect a potential failure at the blood flow in the heart. When everything is normal, the pictures have a yellow color (Photo B). If a problem is found, the yellow is replaced by black!