Module 3

Question 1

Oxyhaemoglobin association

Answer 1

HB4 + 4O2 <–> HB4O8
- gases move from high to low concentration
- HB is carried by partial pressure of O2

Question 2

Arterial blood in average male

Answer 2

15g x 1.34 ml O2 = 20 mL O2 per 100 mL of blood

PO2 is high in arterial blood

Question 3

Po2 is low where!?

Answer 3

At muscle bitch
- 40 mmHg at rest
- HB is 75% saturated

15g c (1.34 mL O2 x 0.75) + (small amount of O2 in plasma)
= 15 mL/100mL blood

Question 4

Amount of HB

Answer 4

15g of HB per 100 mL of blood

Question 5

Arteriovenous Oxygen Difference

Answer 5

• 20 mL O2 per 100mL arterial blood
• 15mL O2 per 100 mL venous blood
  5 mL arteriovenous difference (amount of O2 used for fuel)

Question 6

Exercise effect

Answer 6

• muscle needs more fuel
• cells use more O2
• tissue PO2 reduced
• HB releases more O2

Question 7

High Intensity Exercise Effects

Answer 7

• 40-15mmHg for instance
• saturation of O2 reduces as more is liberated from haemoglobin

Question 8

Exhaustive exercise effects

Answer 8

• PO2 falls to 2-3mL where blood releases almost all O2

Question 9

What causes increased a-VO2 difference?

Answer 9

increased intensity of exercise
- more o2 extracted from arterial blood by working muscles
- can be 3x or more of resting values
- fall in O2 content of venous blood

Question 10

O2 carrying capacity affected by

Answer 10

1. PO2 in blood
2. pH of blood (Bohr)
3. temperature of blood (Bohr)

Question 11

a-VO2 for elite athlete

Answer 11

20 mL of O2 per 100mL arterial
3mL O2 venous
- 17 mL difference

Higher difference due to more O2 used during exerciswe

Question 12

a-VO2 for average athlete

Answer 12

20 mL of O2 per 100mL arterial
5 mL O2 venous
- 15mL difference

Question 13

How does O2 extraction improve from training

Answer 13

• improved capillarisation
• increased mitochondrial density
• increased aerobic enzyme activity

Question 14

Fick Equation

Answer 14

VO2 (mL) = [cardiac output (mL) x a-VO2 difference] / 100