Flexi Says: Pulmonary circulation is the part of the circulatory system that carries blood between the heart and lungs. Deoxygenated blood leaves the right ventricle through pulmonary arteries, which transport it to the lungs. In the lungs, the blood gives up carbon dioxide and picks up oxygen. This gaseous exchange occurs in alveoli sac of lungs through process of diffusion. The oxygenated blood then returns to the left atrium of the heart through pulmonary veins. Systemic circulation is the part of the circulatory system that carries blood between the heart and body. The aorta and other arteries transport the blood throughout the body, where it gives up oxygen and picks up carbon dioxide through the thin walls of blood capillaries via diffusion.
