Exercise physiology

Question 1

Which three system are involved in exercise and breathing - in which order?

Answer 1

Muscle
Heart and blood
Lungs

Question 2

During aerobic respiration, why do you have to breathe out more?

Answer 2

More carbon dioxide is made and do more breathing to remove the carbon dioxide

Question 3

How is the amount of CO2 made during lipid metabolism different to glucose metabolism?

Answer 3

During lipid metabolism, less CO2 is made per oxygen molecule (less breathing required so useful during ventilation of patients

Question 4

What is the ratio of C02 production to O2 consumption called?

Answer 4

respiratory quotient (muscles)
respiratory exchange quotient (mouth)

Question 5

How is the amount of CO2 made during protein metabolism different to glucose metabolism?

Answer 5

Protein is more efficient than glucose (less CO2 made) but less than lipid

Question 6

What is the theoretical maximum for RQ (glucose)?

Answer 6

1

Question 7

What happens to RQ when anaerobic respiration occurs, and why?

Answer 7

RQ goes above one as oxygen consumption doesn’t increase but CO2 production does.

Question 8

Seated at rest, how much oxygen does the average sized human require?

Answer 8

3.5ml/min/kg

Question 9

Why does stroke volume decrease the faster the heart rate goes (beyond a certain point)?

Answer 9

The heart doesn’t have enough time to fill completely

Question 10

Which two things must occur to increases oxygen consumption?

Answer 10

Cardiac output and more oxygen is extracted from the blood by the muscles
allow you to increase your oxygen consumption.

Question 11

What is the equation for VO2 (oxygen consumption)?

Answer 11

VO2 = Cardiac output * (a-v) O2 content [means extraction]

Question 12

How can a person who isn’t getting enough oxygen due to a muscle problem be identified?

Answer 12

mitochondrial disease - oxygen isn’t extracted
pulmonary artery catheter , during exercise the oxygen saturation is still high even if they are exercised (muscle problem)

Question 13

What are two types of exercise?

Answer 13

Incremental exercise - increases in intensity

Steady state exercise - intensity maintained

Question 14

Which two factors change in the lungs to increase oxygen entering the lungs?

Answer 14

breathing rate and tidal volume

Question 15

Why do we only breathe at half the vital capacity?

Answer 15

It requires a lot more effort to use the full vital capacity

Question 16

What causes effects like fainting due to hypoventilation?

Answer 16

pH goes up, fewer protons in blood and more calcium bind to albumin (which can also bind protons) so less calcium causes effects like fainting

Question 17

How does VQ matching differ between at rest and during exercise?

Answer 17

At rest VQ matching isn’t ideal but during early exercise the VQ matching improves

Question 18

At rest, where do most of the blood and air go to in the lungs and how does this change during exercise?

Answer 18

at rest most of the blood and air go to the bottom of the lung
Blood and air go all the way through the lungs during exercise.

Question 19

What happens to ventilation rate as CO2 increases?

Answer 19

As carbon dioxide concentration increases so does ventilation rate. There is close coupling of VE to VCO2.

Question 20

What is the Bohr effect?

Answer 20

The ODC shifts to the right during exercise as hemoglobin has less affinity for oxygen so more unloading.

Question 21

What is the ventilatory compensation point?

Answer 21

At the end of exercise , HCO3- runs out and hyperventilation occurs - chemoreceptors detect this. No more exercise can occur.

Question 22

During steady state exercise how does oxygen consumption change and why is there a time lag between increase in oxygen consumption and exercise?

Answer 22

Oxygen consumption increases and then stays stable. When oxygen is measured at the mouth, there is a time lag between exercise and increase in consumption due to the time it take to get from muscle to heart to the lungs.

Question 23

What is oxygen deficit?

Answer 23

The amount of oxygen consumed isn’t enough to fulfill demand so anaerobic mechanisms begin.

Question 24

What are the two main types of chemoreceptors?

Answer 24

peripheral chemoreceptors - aortic (detects carbon dioxide and O2 but not pH) and carotid bodies (detect all three)
central chemoreceptors - medulla