Question
Countercurrent exchange systems are used in all of the following except gill systems. cetacean flippers. red muscle. osmoregulatory systems. Which of the following is incorrect about gill systems of fishes? Ram ventilation may be used to move water over the gills. Opercular pumping may be used to move water over the gills. The lamellae is where gas exchange occurs. Water leaving the gills has an oxygen tension (content) far higher than the blood leaving the gill. Pressure is higher in the oral cavity than opercular cavity most of the respiratory cycle. Sharks have high levels of urea in their bodies, which is used for ___ and requires ___ to stabilize its toxic effects. buoyancy; squalene buoyancy; TMAO osmoregulation; squalene osmoregulation; TMAO
Explanation / Answer
43) B- red muscle is not a counter-current exchange system itself, but it is in the circulatory system in the red muscle which exchanges heat between red muscle and surrounding.
44)D- blood leaving the gill areas to have a higher oxygen tension than water leaving the gill.
45) D- high level of Urea is for osmoregulation and its toxic effects can be stabilized by TMAO-Trimethylamine oxide.