Explain how a fish is adapted for gas exchange?

A fish had gills, made up of gill filaments containing lamellae, which provide a very large surface area for oxygen to diffuse out of the water as it moves over them. The blood vessels are in very close proximity to the lamellae, allowing a short diffusion pathway. A fish also utilises a countercurrent system, where the blood flows in the opposite direction to the water across the gills. This allows a concentration gradient to be maintained, so oxygen moves into the blood along the entire length of the gill.

Related Biology A Level answers

All answers ▸

How does genetic variation occur in meiosis?


Why is it that an action potential only travels in one direction?


How does a signal move from one neurone to another and how does this process change for different motor responses?


How do the actions of steroid hormones cause proteins to be made?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences