Describe and explain how the human lungs are adapted for efficient gas exchange (3 marks)

  1. There are millions of alveoli (gas exchange surface), so they have a very large surface area collectively, which is further increased by having a folded membrane. A larger surface areas means there is a faster rate of diffusion of oxygen and carbon dioxide.
    2) Alveoli walls only have a single layer of epithelial cells. The walls of capillaries surrounding the alveoli only have a single layer of endothelial cells. Therefore, there is a shorter diffusion pathway, so there is a faster rate of diffusion of oxygen and carbon dioxide.
    3) Ventilation of the lungs brings oxygen into the alveoli and removes carbon dioxide. The circulation of blood through capillaries is constantly bringing in blood with low oxygen. This maintains a steep concentration gradient across the alveolar wall for a faster rate of diffusion for oxygen and carbon dioxide.
Answered by Biology tutor

8831 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

How does synaptic transmission across a neuromuscular junction work?


a) Name a hormone secreted by the ovaries (1 mark). b) A female takes a contraceptive pill that increases the body's levels of progesterone. Explain what effects this has on the female's body and what effects that it has on her other hormones (3 marks)


What is the difference between the Parasympathetic Nervous System and the Sympathetic Nervous System?


How is energy generated from carbohydrates?


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