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Terms in this set (41)

FUNCTIONS OF THE CIRCULATORY SYSTEM
• The circulatory system consists primarily of blood, the heart and a network of blood vessels. The main functions of the circulatory system are gas exchange, hormone and nutrient distribution, as well as waste elimination. The heart pumps the blood throughout the body, which is transported by the blood vessels to the necessary tissues and organs. Gas exchange involves spreading oxygen throughout the body and removing carbon dioxide waste. Oxygen must be delivered to all functioning body cells in order for them to metabolize, or carry out their functions and activities. Blood also transports helpful nutrients and antibodies so that the body's immune system may be healthy and responsive.
OPEN CIRCULATORY SYSTEM
• The open circulatory system is the simpler of the two systems. Here, the heart pumps blood into open cavities, where blood vessels carry the blood throughout the body at a low pressure. There are two major differences between the open and closed system. First, the open system bathes all organs and tissues throughout the body with blood and, second, there are no arteries or major veins to increase blood pressure and direct distribution. Animals with an open circulatory system typically have lots of blood and low blood pressure.
CLOSED CIRCULATORY SYSTEM
• Larger and more active animals, including all vertebrates, have a closed circulatory system. This more complex system includes two major processes: pulmonary and systemic circulation. In the former process, deoxygenated blood is passed through the lungs in order to receive oxygen. Afterward, systemic circulation distributes the newly oxygenated blood throughout the body. In a closed circulatory system, blood is directed through arteries to veins throughout the body. As opposed to bathing all tissues and organs with blood, the blood remains in vessels and is transported at high pressures to all extremities of the body at a rapid rate.
BOTH SYSTEMS HAVE THREE BASIC COMPONENTS:
A circulatory fluid (blood or hemolymph)
A set of tubes (blood vessels)
A muscular pump (the heart)