Lungs & gas exchange

Question 1

Why do we need oxygen

Answer 1

• For the cells to carry out cellular respiration and produce energy that our body needs

Question 2

What is the process of inhaling oxygen and exhaling CO2

Answer 2

• Air is inhaled via the nose / mouth
• The air is transported by the trachea to the two seperate bronchi
• From the 2 bronchi, it is transportedto progressively smaller tubes known as bronchioles
• The air is then held in small air sacks known as alveoli

Question 3

How do alveoli work

Answer 3

• There is a large network of blood capillaries running next to the alveoli (small diffusion distance)
• The blood in these capillaires is deoxygenated. Therefore, oxygen diffuses into the blood from the alveoli. CO2 in the blood will diffuse into the alveoli from where it is then exhaled
• The now oxygenated blood is taken to the cells that require oxygen for cellular respiration

Question 4

Adaptations of alveoli

Answer 4

• 1 cell thick cell wall (small diffusion distance)
• Rich blood supply (maintain strong concentration gradient)
• Large surface area (as there are loads of alveoli)