BIOL 382 Lecture Notes - Lecture 15: Chitin, Extracellular Fluid, Buccal Pumping
Document Summary
Fick"s e(cid:395)uatio(cid:374) states that to (cid:373)a(cid:454)i(cid:373)ize diffusion, respiratory surfaces are typically thin with a large surface area. For gases, the gradient of pressure, not concentration is important. Gases dissolve, diffuse, and react according to pressure, not necessarily concentration. Dalto(cid:374)"s la(cid:449) of pa(cid:396)tial p(cid:396)essu(cid:396)e states that the. Like respiratory tubes? sum of partial pressures of gases in a gas mixture yields the total pressure of the gas mixture. At 20c at sea level the molar concentration of oxygen in air is approximately 9mm, whereas the concentration of oxygen in water under these conditions is less than 0. 3mm. To obtain the same amount of oxygen, an animal that uses water as its respiratory medium must move 30 times more fluid across its respiratory surface than an equivalent organism that uses air as its respiratory medium. He(cid:374)(cid:396)(cid:455)"s la(cid:449) states that gases dissol(cid:448)e i(cid:374) solutio(cid:374) according to their partial pressure and solubility.
