Oxygen Dissociation Curve

Question 1

How does oxygen diffuse into capillaries?

Answer 1

1. The partial pressure of O2 is higher in the alveoli than the capillaries
2. This causes a diffusion gradient
3. The O2 diffuses from the alveoli into the capillary

Question 2

How does carbon dioxide diffuse into alveoli?

Answer 2

1. The partial pressure of CO2 is higher in the pulmonary capillary than in the alveoli
2. This causes a diffusion gradient
3. CO2 diffuses from the capillaries into the alveoli

Question 3

How is oxygen released into muscles?

Answer 3

1. When oxy haemoglobin reaches the muscles, the hb releases the oxygen
2. The oxygen diffuses into the muscles
3. Here it joins with myoglobin, which stores the oxygen for the mitochondria
4. Made easier as myoglobin has higher affinity for oxygen than hb

Question 4

What is the Bohr shift?

Answer 4

When an increase in blood carbon dioxide and a decrease in PH levels results in a reduction of the affinity of hb for oxygen

Question 5

What is the advantage of the Bohr shift?

Answer 5

During exercise, the hb will be forced to release its carbon dioxide, meaning more oxygen can get to the working muscles where it is needed to make energy

Question 6

What are the stages of the Bohr shift?

Answer 6

1. Exercise produces an increase in blood temperature
2. There is also an increase in blood carbon dioxide concentration
3. Oxyhemoglobin dissociation curve shifts to the right
4. Resulting in less saturation of hb with oxygen
5. Therefore an increase in oxygen release