CIRCULATORY SYSTEM

 

The circulatory system has different functions. It transports gases like oxygen from lungs to cells and carbon dioxide from cells to lungs. It transports nutrients like glucose. It also transports wastes from cells to organs that eliminates them. The circulatory system has cells that fight infections and foreign bodies. It maintains pH and fluid levels. Lastly, it helps maintain body temperature especially in endothermic animals. There are two types of circulatory systems, one is an open system and the other is a closed system. In an open system, blood isn't contained in the blood vessels. In a closed system, blood is actually contained in the blood vessels. Structures like the heart, blood and blood vessels are a part of this system. 

Advantages of animals with an open system are able to control over their body temperature. For example, it prevents them from dying out. They're not exposed to pressure as much which lets some organisms live very deep in the ocean. Animals with a closed system have a good control over the oxygen's delivery to the tissues. The lymphatic system helps decrease the pressure of tissues. Blood is very important because it helps fight off infections. For example, white blood cells act as antibodies and prevent diseases. 

Disadvantages of animals with open systems are low metabolism. They have low metabolism because of their diffusion limitations. Transportation in an open system is slow, therefore there's a limit on the oxygen the take and the blood flow. Animals with a closed system have high blood pressure. The heart maintains the circulation of the blood around our whole body with high pressure. 

Sources:

http://daman92.hubpages.com/hub/Circulatory-System

http://www.arthursclipart.org/frogs/frogs/page_01.htm

http://library.thinkquest.org/26153/marine/arthro.htm

http://sciencenotes.wordpress.com/2012/01/21/traces-of-evolution/earthworm-circulatory-system-3d/

http://www.cartage.org.lb/en/themes/sciences/zoology/AnimalPhysiology/CirculatorySystem/CirculatorySystem.htm

Holt, Rinehart and Winston Modern Biology

Austin: Holt, Rinehart and Winston, 2002