A-VO2 difference and HR ECK

Question 1

What is A-VO2 difference?

Answer 1

• it is the difference in O2 content in arterial blood and venous blood

Question 2

why is A-VO2 difference low at rest?

Answer 2

• The muscles do not need as much O2 compared to when you are exercising.
• As a result, much of the blood going past the muscles is still oxygenated.

Question 3

What happens to A-VO2 difference during exercise?

Answer 3

• More O2 intake means that more O2 diffuses into the blood.
• Blood O2 volume in arteries increase massively
• O2 content in veins massively decreases due to O2 intake from muscles
• A-VO2 diff increases.

Question 4

How does A-VO2 effect gaseous exchange?

Answer 4

• more O2 taken in
• causes an increase in blood O2
• Allows for more O2 to be removed.

Question 5

During a game, a player’s VO2-diff increases. What is the significance of this? (3 marks)

Answer 5

• Difference between O2 content in arterial blood and venous blood.
• More O2 is used by muscle which is why there is an increase in A-VO2
• More O2 is diffused into the capillaries via increase in gaseous exchange.
• This improves performance.

Question 6

Control of HR ECK

STEP 1

Answer 6

• adrenaline is released and detected by hormonal receptors

- causes anticipatory rise

Question 7

Control of HR ECK

STEP 2

Answer 7

• chemo receptors detect increase in CO2 and blood acidity

Question 8

Control of HR ECK

STEP 3

Answer 8

• impulses are then sent to CCC in medulla

Question 9

Control of HR ECK

STEP 4

Answer 9

• CCC sends impulses down symp NS to SA node in the heart.

Question 10

Control of HR ECK

STEP 5

Answer 10

-HR increases