The left ventricle pumps blood through the aortic semilunar valve into the aorta. From the aorta, blood enters into systemic circulation throughout the body tissues until it returns to the heart via the vena cava and the cycle repeats.he left ventricle pumps blood through the aortic semilunar valve into the aorta. From the aorta, blood enters into systemic circulation throughout the body tissues until it returns to the heart via the vena cava and the cycle repeats.
The signs and symptoms of superior mesenteric artery syndrome vary but may include: 1  Feeling full quickly when eating. 2  Bloating after meals. 3  Burping (belching)  Nausea and vomiting of partially digested food or bile-like 1  liquid. Small bowel obstruction.  Weight loss.
1 Superior vena cava syndrome is most often caused by compression of the vein (the superior vena cava), that returns blood from the upper body back to the right atrium of the heart by tumor.  Symptoms include swelling of the face and arms associated with shortness of breath.