BIO202H5 Study Guide - Midterm Guide: Perfusion, Tonicity, Nephridium
Document Summary
Hence, the concentration gradient increases and diffusion is maximized: ventilation increases p1 due to the gas exchange past the respiratory surface, whereas, perfusion decreases p2 due to the movement of body fluids (blood, concurrent exchange is when water flows in opposite direction of the blood flow, maximizing the concentration gradient (p1 p2, oxygen from the water diffuses into the blood raising its oxygen content, crosscurrent exchange in birds, exchange in which the fluids are moving in opposite directions, however, the tubes they"re flowing in are perpendicular to each other, first cycle: oxygen flows into the posterior sac. Countercurrent exchange deoxygenated blood from the heart flows in opposite direction to the water to maximize concentration gradient. The buccal force pump forces water through the gills when the mouth closes, while the opercular suction pump draws water through the sieve formed by the gills when the opercula open.
