NS - Respiration III

Question 1

Does increasing blood flow (PERFUSION) alter blood O2 saturation?

Answer 1

No - in a normal lung

Question 2

What two physiologically regulated factors determine the rate of O2/CO2 transfer between alveolus and tissue?

Answer 2

1) Rate of alveolar ventilation

2) Blood flow (Perfusion)

Question 3

What is a problem with alveolar ventilation?

Answer 3

Not all the alveoli are ventilated or perfused equally

Question 4

How is this inherent problem resolved?

Answer 4

Ventilation-Perfusion matching

Question 5

What is hypoxic vasoconstriction?

Answer 5

When pO2 within the alveoli decreases, there is a decrease in perfusion to that alveolus (Acts to rest V:Q ratio)

Question 6

When is haemoglobin almost completely saturated?

Answer 6

When pO2 is 80mm Hg or above

Question 7

What occurs between the 4 subunits in haemoglobin?

Answer 7

Binding of oxygen to one subunit induces conformational changes in the remaining active sites (enhancing their affinity)
- Sigmoidal curve

Question 8

What causes the dissociation curve to shift right? (4)

Answer 8

1. Increased H+ ions (Lower pH)
2. Increased CO2
3. Increased temperature
4. Increased BPG

Question 9

How does 2,3-Bisphosphoglycerate alter the position of the O2/Hb curve?

Answer 9

Binds to a specific site in the β chain of Hb and it decreases its oxygen affinity

Question 10

Why does fetal Hb have a higher affinity for O2 than human?

Answer 10

Fails to interact with 2,3-Bisphosphoglycerate