Alveoli

Question 1

What are alveoli adapted for?

Answer 1

gas exchange by diffusion between air in the lungs and blood in capillaries

• absorbing oxygen (needed for respiration) into the blood from the air in the lungs
• transferring carbon dioxide (produced by respiration) from the blood into the lungs

Question 2

What are gases required and produced by?

Answer 2

cellular (aerobic) respiration

Question 3

exchange surface

Answer 3

an area of the lungs that is adapted for efficient transfer of gases

Question 4

name for the process of breathing in/out?

Answer 4

ventilation

Question 5

respiratory system

Answer 5

the organ system where air is taken into and out of the body, and gas exchange happens

Question 6

adaptions of alveoli for efficient gas exchange (4)

Answer 6

• small size: each one alveolus is a small sphere, giving it a larger surface:volume ratio (allowing for more efficient diffusion)
• millions of them: creates large surface area for diffusion of gases
• constant blood flow though capillary and ventilation of alveolus: maintains concentration gradient as gases are being removed continually
• walls of alveoli and capillaries are only one cell thick: minimises diffusion distance

Question 7

Why do humans need to have a circulatory system?

Answer 7

• cells around body all need or produce gases
• they can’t absorb them from air, so the blood supply provides the gases
• the circulatory system reaches all of these cells individually
• without it there would not be oxygen supplise for respiration