Veins - the most important part of the system of the body "vascular-heart", closely correlated with lymph and arteries. Through the venous system is provided by the flow of the lymph and blood to the heart.
Veins of the systemic circulation is a closed system of vessels that collect oxygen-poor blood from all body cells and tissues, combined with the following subsystems:
Venous blood is the blood that flows back from all of the cell systems and tissues saturated with carbon dioxide, containing products of metabolism.
Medical manipulations and studies are conducted mainly with the blood, which contains the end products of metabolism and smaller amount of glucose.
The Arterial blood is the blood that flows to all cells and tissues from heart muscle is saturated with oxygen and hemoglobin that contains nutrients.
Oxygenated arterial blood circulates through the arteries of a large circle and through the veins of lesser circulation.
The Walls of veins are much thinner than blood, because blood flow in them and the pressure is lower. Stretched veins easier, their elasticity is lower than arteries. The valves of the vessels are usually situated in front, which prevents the reflux of blood. In a large number of the valves of the veins in the lower extremities. Veins are also located in the semilunar valves of the folds of the inner shell, which has a particular elasticity. In the arms and legs there are veins situated between the muscles is when the muscle contraction allows the blood to return back to the heart.
A Large circle originates in the left ventricle of the heart, and it goes from the aorta with a diameter of three inches. Further, the oxygen-Laden blood enters the arteries by decreasing the diameter of the blood vessels to all organs. Giving all the nutrients, the blood is saturated with carbon dioxide and goes back through the venous system through the smallest vessels - venules, the diameter gradually increases, approaching the heart. Venous blood from the right atrium is pushed while in the right ventricle and starts the pulmonary circulation. Entering into the lungs, the blood re-filled with oxygen. Through the veins to the left atrium receives arterial blood, which is then pushed into the left ventricle of the heart, and the circle repeats itself.
Arteries and veins of the systemic circulation include the aorta, and branch out from her smaller, upper and lower hollow vessels.
The Small capillaries are in the human body an area of about one and a half thousand square meters.
Veins of the systemic circulation carry depleted blood, except the pulmonary and umbilical that carry blood rich in oxygen blood.
Driving force for blood flow is the energy described by the heart as well as the difference of the pressure parts of the vessels.
The Upper Vena cava collects the venous blood of the upper body - head, neck, sternum and partly in the abdominal cavity and into the right atrium. The valves of the vessels are absent. The process is as follows: saturated with carbon dioxide the blood of the upper vein flows into the region of the pericardium, lower - in the area of the right atrium. The system of the superior Vena cava divided into the following parts:
The lower hollow is the connection of the iliac veins on both sides in the region of 4 - 5 vertebrae of the lower back, takes the venous blood of the lower parts of the body. Bottom hollow is one of the largest veins in the body. In length it is about 20 cm in diameter to 3.5 cm from the inferior Vena cava, the outflow of blood from the legs, pelvis and abdomen. The system is divided into these components:
Portal vein got its name due to the ingress of the trunk at the gate of the liver, and collecting venous blood from digestive organs - stomach, spleen, bowel thick and thin. Her vessels behind the pancreas. The length of the vessel is 500-600 mm, the diameter of 110-180 mm.
Tributaries miscelaneo trunk are the superior mesenteric, inferior mesenteric and the splenic vessels.
System anatomy of the portal vein at its core involves the vessels of the stomach, intestines large and small departments, pancreas, gallbladder and spleen. In the liver it is divided into right and left and then branches out into smaller veins. In the end they combine into a Central vein of the liver, Podmoskovye vein of the liver. And in the end are formed three or four hepatic vessel. With this system blood digestive organs passes through the liver, entering the subsystem of the inferior Vena cava.
Superior mesenteric Vienna blood accumulates in the roots of the mesentery to the iliac colon, pancreatic, right, and middle colon, the iliac colon and the right zheludochka-omental veins.
Inferior mesenteric Vienna is formed from the upper rectal, sigmoid and left colic veins.
Vienna has Splenic the splenic blood, the blood of the stomach, duodenum and pancreas.
From the base of the skull to the supraclavicular basin vessel is a jugular vein. The systemic circulation includes the data of the vein, which is a key collections of blood from the head and neck. In addition to the internal, blood from the head and soft tissues and collects the external jugular vein. Outer starts at the ear and goes down along the sternocleidomastoid muscle.
Veins running from the external jugular
Internal jugular vein starts at the jugular the cavity of the skull, as a companion of the external and internal carotid arteries.
Thanks to the continuous movement of blood in the arteries and veins of the systemic circulation are provided with the basic functions of the system:
Vessels of the systemic circulation represents a complex network, providing blood to all organs in contrast to the small circle. Optimal functioning of the system of upper and lower hollow veins leads to proper blood flow to all organs and tissues.
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