BIOL 1002 Chapter : Ch 32 Notes
Document Summary
Overview: the need for circulation (and circulatory systems) arose, as animals got larger, small (and thin) animals have all of their cells in close proximity to the outside environment. This means there is a very short distance that food and oxygen have to travel to get to the center of each cell. Likewise, the distance that waste and co2 have to travel to get out of the cell is also very short: materials (good or bad) can efficiently move over short distance in an organism by diffusion. Larger distances require some energy requiring process (active transport, circulation, etc. In larger animals since diffusion is not effective enough to get the good things (nutrients and oxygen) in and get the bad things (waste and carbon dioxide) out, circulation is required. In the open circulatory system part of the channel that the fluid circulates through is an open space within the body called the hemocoel (blood cavity)
