Vena Cava - Function and definition
Vena Cava are the two largest veins in human body together called the venae. These veins collectively return deoxygenated BLOOD to the HEART. Both of them deplete all the blood into the right atrium. The superior vena cava, large but short vein, brings blood from the upper part of the organism, the head and upper limbs, and empties into the top of the right atrium. The inferior vena cava (IVC), the largest vein the organism, leads alongside the abdominal cavity carrying from the lower part of the body and entering to the bottom of the right atrium, the back side of the heart. A valve at the juncture that separates the inferior vena cava and the right atrium is called the Eustachian valve and disables the gravity causing the blood to pull back into the inferior vena cava. No valve borders between the superior vena cava and the right atrium.
Vena Cava and Health Problems
There are several health problems associated with these two veins being compressed. For example, the IVC may be compacted by an external pressure of an enlarged aorta, some kind of CANCER, or uterus during the third trimester of PREGNANCY. During this period, the uterus compresses the vein in the right side position; and thus, unconscious pregnant women should be turned on their left side in order to relieve from an excessive pressure on the vein and facilitate the blood circulation within. However, the impaction of the inferior vena cava occurs rarely, it is life-threatening. These health complications called also the inferior vena cava syndrome (IVCS) are usually caused by a obstruction of a deep vein thrombosis or tumor, or liver transplantation, for instant. The most common symptom of the IVCS is edemas of the lower extremities. Another signs such as shortness of breath followed by facial edemas or arm swelling as well as cough or headaches are most probably the symptoms of the superior vena cava obstruction (SVCO). This syndrome is usually caused by a blockade within the vein created by an accumulation of malignancies such as cancerous tumors in 90% of cases. The superior vena cava syndrome is possible to diagnose from the X-ray pictures or during CT scanning of the chest. These techniques help to distinguish the cause of the problem as well as to determine the stage of the disease progress. The treatment may include the usage of medication or chirurgical removal. The radiation therapy helps to decrease or eliminate the unpleasant and painful symptoms. Unfortunately, even with proper treatment, the majority of patients (around the age of 54) suffering from the SVCS dies within two and a half years.
For further discussion of the superior vena cava and the inferior vena cava within the context of cardiovascular structure and function please see the overview section “The Cardiovascular System.”
See also AORTA; PULMONARY ARTERIES; PULMONARY VEINS.
