2012年2月14日星期二

blood vessels

Venous blood back to the heart is mediated by vascular, originated from the capillaries, stop at the atrium. Body of the blood in the veins contain more carbon dioxide, scarlet red. In pulmonary vein blood contains more oxygen, bright color. Small vein in the capillaries, in the heart in the process gradually merged into vein, vein, then into the atrium.

The blood back to the heart, blood vessels. Body of the blood in the veins contain more carbon dioxide, scarlet red. In pulmonary vein blood contains more oxygen, bright color.

Vein is the cardiovascular system, blood return to the heart of the guide conveying pipeline.

The initial intravenous in the capillaries in the atrium, termination. Small vein in the capillaries, in the heart in the process gradually merged into vein,varicose veins tips vein, then into the atrium.

Vein wall thin, smooth muscle and elastic fibers are less, lack of contractile and elastic, lumen section relatively flat. Venous blood back to the heart is mediated by vascular, originated from the capillaries, stop at the atrium. Body of the blood in the veins contain more carbon dioxide, scarlet red. In pulmonary vein blood contains more oxygen, bright color. Small vein in the capillaries, in the heart in the process gradually merged into vein, vein, then into the atrium.

Vein wall thin, smooth muscle and elastic fibers are less, lack of contractile and elastic, lumen section relatively flat. Venous capacitance vessels, usually accommodating body 70% of the blood, the superficial veins can be seen in the skin, upper and lower extremity superficial vein is often used to draw blood, intravenous injection, blood transfusion and infusion. Vein wall of venous valve of lower limb vein, especially in more developed, it can prevent the backflow of blood, so that the flow of blood to the heart. But within the peritoneal cavity of large veins, such as portal vein, the superior and inferior vena cava without venous flap, can be due to intra-abdominal pressure affects to the venous blood return.

Function

Capacitance vessels, usually accommodating body 70% of the blood, the superficial veins can be seen in the skin, upper and lower extremity superficial vein is often used to draw blood, intravenous injection, blood transfusion and infusion.

Vein wall of venous valve of lower limb vein, especially in more developed, it can prevent the backflow of blood, so that the flow of blood to the heart. But within the peritoneal cavity of large veins, such as portal vein, the superior and inferior vena cava without venous flap, can be due to intra-abdominal pressure effect of venous blood return.

Classification

Systemic veins can be divided into veins of pulmonary circulation and systemic circulation of the vein of two most.

Pulmonary vein left, right to left, respectively, the left inferior pulmonary vein and the right, the right inferior pulmonary vein. These are from the pulmonary vein portal, to professional into the posterior left atrium. Pulmonary venous to arterial blood with high oxygen delivery to the heart. Venous systemic venous volume, long stroke, wide distribution, including superior vena cava system, inferior vena cava system ( including the hepatic portal system ) and cardiac vein system.

Superior vena cava system is the collection of head and neck, upper limb and chest back at the venous blood return to the heart of the pipeline.

Inferior vena cava system is the collection of abdominal, pelvic, lower limb venous blood back to the heart of a series of pipes.

Veins of heart is the heart of the venous blood collection tube.

Portal venous system is mainly a collection of abdominal digestive tract, pancreatic and splenic venous blood into the hepatic vein conduit, into the portal vein in liver, intrahepatic and into the capillary network ( with hepatic artery blood into liver sinusoids ), and then by the hepatic vein inferior vena cava flow back into the heart.

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