Bloody or tarry stools refer to a stool sample thatâs either dark red or black in color. Bloody or tarry stools can indicate bleeding or other injuries in your gastrointestinal tract. You may also have dark, discolored bowel movements after eating dark-colored foods.
The longest vein in the body is the great saphenous vein, a superficial vein found in the leg.he deep veins are essenti â¦ ally a column of blood running from your head to you feet and so when one is standing are under high pressure. In order to keep this pressure away from the frail superficial veins the penetrating veins have valves.
The inferior vena cava is the largest vein in the human body. It collects blood from veins serving the tissues inferior to the heart and returns this blood to the right atrium of the heart.he inferior vena cava is the largest vein in the human body. It collects blood from veins serving the tissues inferior to the heart and returns this blood to the right atrium of the heart.