Which of the below represents the countercurrent mechanism in fish?
Which of the below represents the countercurrent mechanism in fish?
The correct option is B 2
The 2nd diagram represents countercurrent mechanism, so called because the blood and water flows in opposite directions, making respiration in fishes efficient. When the water enters in through the mouth, it is richly oxygenated let us say it has 100 PPm of O2init.Nowwhenitleavestheotherside,throughthegills,ithasgivenupO2tothebloodandthelevelofO2 has dropped to say 20 PPm. Now the blood, which is flowing in the opposite direction has 40 PPm here, and as it flows it gains oxygen and by the time it reaches the opening of the operculum where water enters it would have gone up to 80 PPm. Thus there is a constant gradient that is created which helps oxygen diffusion to happen more effectively.
2
The 2nd diagram represents countercurrent mechanism, so called because the blood and water flows in opposite directions, making respiration in fishes efficient. When the water enters in through the mouth, it is richly oxygenated let us say it has 100 PPm of O2init.Nowwhenitleavestheotherside,throughthegills,ithasgivenupO2tothebloodandthelevelofO2 has dropped to say 20 PPm. Now the blood, which is flowing in the opposite direction has 40 PPm here, and as it flows it gains oxygen and by the time it reaches the opening of the operculum where water enters it would have gone up to 80 PPm. Thus there is a constant gradient that is created which helps oxygen diffusion to happen more effectively.
