BSC 197 Lecture Notes - Lecture 29: Surface Tension, Respiratory Pigment, Myoglobin
29 Dec 2016
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Gas exchange will occur across cell membranes in structure. Membranes need to be exposed to aqueous environment. Respiratory surfaces are kept moist by the organism. 3 main types of structures: gills. Highly vascular structures extending from the body of aquatic animals. Often surface area of gills is greater than the surface are of the rest of the animal. Function: ventilated by animal moving through water or they may deliberately pass water over gills while not moving, there is a system of countercurrent exchange (like in blood heating) in which: Blood with lowest oxygen pressure is exposed to ventilated water last. Blood with middle pressure is exposed sooner. Fish can extract 80% of oxygen from ventilated water: tracheal systems (insects use these) A network of tubes that branch throughout water. Any single area of tissue would be near a gas exchange structure. There may be no need to combine circulation and respiration.
