0 votes
3.1k views
in Biology Form 2 by
Describe the mechanism of gaseous exchange in the gills of a bony fish.

1 Answer

0 votes
by
The mouth opens and the floor of the mouth is lowered ;hence volume of the buccal cavity increases and pressure falls; this causes water to rush into the mouth;
opercula bulge outwards raising the volume; and a fall in the pressure of the buccal cavity.
Water is forced to flow over the gills at high pressure; This is enabled by the higher external pressure; which presses both opercula initially before opening the mouth and the opercula.;
The water entering the mouth has more oxygen; and low in carbon (iv) oxide; which creates a steep diffusion gradient;
Oxygen diffuses from the water to the blood in the capillaries and combines with hemoglobin;
Carbon (iv) oxide diffuses from the blood capillaries into the water
Welcome to EasyElimu Questions and Answers, where you can ask questions and receive answers from other members of the community.

6.4k questions

9.6k answers

6 comments

590 users

...