W6: Guest Lecture

Question 1

OXYGEN CONSUMPTION (VO2)

Oxygen Transport System

Answer 1

Question 2

The Fick Principle:

Answer 2

Question 3

ADAPTATIONS TO ENDURANCE TRAINING that explain why Vo2 max increases

Question 4

What are central adaptations?

Answer 4

“Central”

• Adaptations related to O2 delivery

in red

Question 5

What are peripheral adaptations?

Answer 5

“Peripheral”

• Adaptations related to O2 extraction

in purple

Question 6

Why is HR lower at rest?

Answer 6

parasympathetic dominance on the SA node

Exercise ➜ ↑ PNS Activity & ↓ SA Node
Intrinsic Firing Rate ➜ ↓ HRrest

Question 7

How does HR vary during submaximal excersize?

Answer 7

Exercise ➜ Sympathetic Drive ➜ HR
for same intensity

Question 8

How to determine maximal heart rate?

Answer 8

Question 9

HR variation in different individuals

Answer 9

Question 10

What are the 3 Determinants of SV?

Answer 10

1. Preload
2. Afterload
3. Myocardial Contractility

Question 11

What is Preload?

Answer 11

Preload is the degree of stretch of the cardiac muscle fibers at the end of diastole, determined by the volume of blood returning to the heart.

Question 12

What is Afterload?

Answer 12

Afterload is the resistance the left ventricle must overcome to eject blood during systole.

Question 13

What is myocardial contractility?

Answer 13

Myocardial contractility is the ability of the heart muscle to contract and generate force independently of preload and afterload.

Question 14

What is Exercise-induced cardiac remodeling (EICR; aka Athlete’s Heart)?

Answer 14

● Repetitive and sustained exercise ➜ heart’s mass and volume increase
○ Athletes have 10–20% increase in LV wall thickness and 10–15% increase in ventricular chamber size vs. individuals of similar age and size
● EICR ➜ increased preload and myocardial contractility ➜ increased SV

Question 15

How does blood volume affect VO2 max

Answer 15

1. ↑ BV ➜ ↑ venous return ➜ ↑preload ➜ ↑ SV
2. ↑ RBC ➜ ↑ O2 carrying capacity