Gills Affecting The Rate Of Gas Exchange In Water

Fish live in water and it is essential that they do as their gills only allow them to take in oxygen from the water. The percentage of oxygen is the water is significantly lower than the amount of oxygen in the air. Fish have adapted to be able to filter oxygen from the water despite its low percentage. Gas exchange in fish occurs in their gills which is supported by a bony arch. Fish take water in through their mouths. Water enters via a fish’s open mouth, its opercula close and stop water from leaving before being forced through the gill filaments. Once the fish has shut its mouth and the water has passed through the gills, the opercula then opens to allow the existing water to flow out.
A fish’s gills have specifically adapted to efficiently remove oxygen from the moving water. Gills are made up of tissue like structures called filaments. These filaments have small bumps going over each side of the filaments which are called lamella. Lamella greatly increase the surface area of the gills and make their exchange of oxygen and carbon dioxide efficient. Lamella are also very thin, ensuring the some percentage of oxygen in the water and diffuse quickly into the fish’s circulatory system.
Moisture of a fish’s gills is not an issue as a fish’s environment is in the water. It allows for their gills to be external as there is no risk of desiccation. It is essential for the gills to be in water as the water flows between each filament and helps the to sway apart. Out of water, the thin filaments stick together and gas exchange couldn’t