Types of circulation
There are three types of circulation found within humans. Systemic circulation, pulmonary circulation and portal circulation. Systemic circulation describes the movement of blood from the heart via arteries to the periphery, and back to the heart via the veins. Pulmonary circulation describes the movement of blood from the heart to the lungs and back to the heart. Portal circulation describes the movement of blood from the gut area via the liver to the heart. In animals circulation can be divided into the open and closed circulation. Open-is found in insects and it involves hemolymph forming (leaving blood vessel) and directly bathing the target tissues. Closed- is found in animals and involves the processes mentioned earlier in this article.