Human: Circulatory System
The circulatory system is an organ system that passes nutrients (such as amino acids, electrolytes and lymph), gases, hormones, and blood cell to and from cells in the body to help fight diseases, stabilize body temperature, and to maintain homeostasis. There are two types of circulatory systems, Closed, and Open; and humans have the Closed Circulatory system. The closed circulatory system means that the blood that is traveling through the body never leaves the network of arteries, veins and capillaries. There are two types of circulation; pulmonary and systemic circulation. The pulmonary circulatory system is the portion of the cardiovascular system in which deoxygenated blood is pumped through the right atrium, then to the right ventricle away from the heart, through the pulmonary artery, to the lungs. That is where the blood is oxygenated, and then sent back to the heart through the pulmonary vein to the left atrium, then to the left ventricle where it is sent to the major arteries. Systemic circulation is the portion of the cardiovascular system which transports oxygenated blood away from the heart, to the rest of the body, and returns oxygen-depleted blood back to the heart. In the blood that the body circulates are RBC, WBC, platelets, and plasma. The red blood cells (RBC) are erythrocytes. The disc shaped cells are produced in the bone marrow and commonly have immune-stimulating polysaccharides called antigens on the surface of their cells. The white blood cells (WBC) also referred to s leukocytes are also produced in the bone marrow, but have a different function. They are commonly known for playing a major role in the immune system, but scientists also believe that they play a role in allergic reactions. The platelets in the blood are also produced in the bone marrow. They serve as a starting material for blood clotting, The platelets adhere to damaged blood vessel walls, and thromboplastin is liberated from the injured...