The pulmonary circuit carries deoxygenated blood. The right auricle receives the impure blood by superior and inferior vena cava, then the blood enters the right ventricle. From the right ventricle, the deoxygenated blood moves to the lungs by the pulmonary artery.
In the lungs, the deoxygenated blood gets oxygenated and enters the left ventricle through pulmonary veins. The pureblood then passes into the left ventricle and then the ventricle pumps the oxygenated blood to different parts of the body. This blood passes to the body aways from the heart by aorta. When the blood gets deoxygenated, it again enters the right auricle. In this way, double circulation occurs and both types of blood do not mix together.
Endocrine Signaling Signals from distant cells are called endocrine signals; they originate from endocrine cells. In the body, many endocrine cells are located in endocrine glands, such as the thyroid gland, the hypothalamus, and the pituitary gland.
