Circulatory System
Circulatory system, cardiac location and structures, the heart is the driving force of the circulatory system, contracting about 70 times/minute to pump an adequate volume of blood with sufficient pressure to perfuse all body organs. The muscular organ weights from 300 to 400g, it’s located within the mediastinum of the thoratic cavity. Living things must be capable of transporting nutrients, wastes and gases to and from cells. Single-celled organisms use their cell surface as a point of exchange with outside environment. Multicellular organisms have developed transport and circulatory systems to deliver oxygen and food to cells and remove carbon dioxide and metabolic wastes. Sponges are the simplest animals, yet even they have a transport system. Seawater is the medium of transport and is propelled in and out of the songe by ciliary action. Simple animals, such as the hydra and planaria, lack specialized organs such as hearts and blood vessels, instead using their skin as exchange points for material. This, however, limits the size an animal can attain. To become larger, they need specialized organs and organs system. The heart has three tissue layers: the epicardium (outer layer), the myocardium (middle layer),and the endocardiu
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Some common words found in the essay are:
, ventricle prevents, left atrium, venous blood, blood flow, ventricle prevents flow, central nervous system, controls blood flow, muscle fibers contract, left atrium mitral, central nervous, blood pulmonary, systemic circulation, atrium mitral, cell bodies, nervous system,
Approximate Word count = 998
Approximate Pages = 4 (250 words per page double spaced)
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