Gaseous exchange

Question 1

What does gaseous exchange involve?

Answer 1

• Getting O2 from the lungs (alveoli) and into the blood. Then getting it to the working muscles to be used during exercise.
• Also, removing CO2 from the muscles and back into the blood, where it is transported to the lungs to be expired.

Question 2

Define partial pressure.

Answer 2

The pressure exerted by a single gas in a mixture of gases.
- Expressed as pO2 mmHg/ pCO2 mmHg.
- Measured in millilitres of mercury (mmHg).

Question 3

Define diffusion.

Answer 3

• The movement of gas from areas of high concentration to areas of low concentration.

Question 4

Define diffusion gradient.

Answer 4

• The rate/ speed diffusion occurs.
• The greater the difference between the mmHg values, the faster that diffusion will occur.
• High gradient= fast diffusion.
• Low gradient= slow diffusion.

Question 5

The process pt.1

Answer 5

1. Breathe in.
2. Partial pressure of oxygen is higher in the lungs (alveoli) than the blood.
3. Oxygen diffuses into the blood- gas moves from an area of high concentration to areas of low concentrations.
4. The rate that diffusion occurs depends on the diffusion gradient.
5. Diffusion is constant until both sides are equal.
6. Blood becomes oxygenated.

Question 6

The process pt.2

Answer 6

7. Blood moves to the muscles.
8. The same process occurs and the oxygen diffuses from the blood into the muscles.
9. Oxygen is used in muscular contractions.
10. CO2 is produced as a waste product.
11. Partial pressure of CO2 increases.
12. The above process if reversed to allow CO2 to be diffused into the blood to be transported to the lungs and then be expired.