BISC 101 Lecture Notes - Lecture 10: Cellular Respiration, Partial Pressure, Intercostal Muscle
15 Dec 2017
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Document Summary
Respiratory and circulatory systems co-evolved to solve some major challenges faced by most animals. Firstly, because animals are active, aerobic organisms, animal cells must be efficiently supplied with oxygen so that they can use energy from food molecules to produce large numbers of atp via cellular respiration. When oxygen is lacking, animal cells must resort to fermentation to produce a smaller number of atp per food molecules, and will produce lactic acid as a by- product. Secondly, because animals are multicellular, and diffusion is a very slow process even over short distances, animals cannot rely on diffusion alone to deliver the necessary oxygen to all cells. Circulatory systems, in general, use a muscular heart to circulate blood within the body, so that every cell is efficiently supplied with needed nutrients, and wastes are efficiently removed. In both systems, the exchange surfaces are kept as thin as possible (1-2 cells thick) so that diffusion distances are minimized.
