CV changes during exercise

Question 1

The 5-6 fold increase in cardiac output during exercise is due to an increase in what?

Answer 1

Stroke volume

Question 2

Why is there a decrease in TPR during exercise?

Answer 2

Vasodilation in active muscle

Question 3

Why is there a decrease in VO2 during exercise?

Answer 3

More blood is being redistributed to the tissues

Question 4

At what 2 locations does SNS stimulation during exercise cause vasoconstriction?

Answer 4

1. Arterioles to decrease flow to non-active muscle

2. Veins to increase MCFP which increases VR

Question 5

During exercise, does AO2 increase or decrease?

Answer 5

Stays relatively constant

Question 6

There is a greater AVO2 difference during exercise due to which variable changing?

Answer 6

VO2 decreasing

Question 7

SNS stimulation during exercise is due to what 3 things?

Answer 7

1. Cerebral cortex stimulation
2. Reflex signals from active joint receptors & muscle spindles
3. Local chemoreceptor signals originating in the active muscle

Question 8

The SNS effects of increased HR and SV (CO) during exercise induce vasoconstriction or vasodilation at the heart?

Answer 8

Vasodilation from local metabolic factors

Question 9

How do we maintain slightly increased blood pressure during exercise?

Answer 9

SNS stimulation of vascular smooth muscle in walls of arteries

Question 10

Do the brain and lungs have a strong vasocontrictor response from SNS stimulation?

Answer 10

NO, weak response that doesn’t limit blood flow (we don’t want to reduce blood flow to these areas!)

Question 11

What is the increase in SBP during exercise due to?

Answer 11

Increased CO

Question 12

Is the increase in SBP larger, equal to, or smaller than the decrease in TPR during exercise?

Answer 12

Greater than

Question 13

What changes occur to DBP during exercise?

Answer 13

Slight increase, may decrease

Question 14

What changes occur to pulse pressure during exercise?

Answer 14

Increase because the increase in SBP is larger than the change in DBP

Question 15

Is the increased blood flow to the active muscle during exercise due to SNS?

Answer 15

NO! Due to local release of tissue metabolites in response to the increase in metabolism
-Adenosine, CO2, K, histamine, lactic acid

Question 16

What are the only 2 CV factors to decrease during exercise?

Answer 16

TPR and VO2

Question 17

What is VO2 max?

Answer 17

The maximum volume of oxygen that one can take up from the lungs and deliver to the tissues per minute

Question 18

What is VO2 max a function of?

Answer 18

CO and AV O2 difference

Question 19

What occurs if energy demands of exercise cannot be met by oxidative phosphorylation?

Answer 19

Oxygen debt (respiration remains elevated after exercise to repay debt)

Question 20

Extra O2 is used in oxygen debt to:

Answer 20

Restore metabolite levels

Metabolize lactate generated by glycolysis

Question 21

How do we maintain slightly increased blood pressure during exercise?

Answer 21

SNS stimulation of vascular smooth muscle in the walls of arteries

Question 22

Do the lungs and brain have strong vasocontrictor responses due to SNS stimulation?

Answer 22

NO, weak constrictor response that doesn’t limit blood flow

we don’t want to reduce blood flow to these areas!

Question 23

What happens to pulse pressure during exercise?

Answer 23

Increases (because the increase in SBP is larger than the increase in DBP)

Question 24

What is the increase in SBP during exercise due to?

Answer 24

Increased CO

Question 25

Is the increase in SBP during exercise larger or smaller or equal to the decrease in TPR?

Answer 25

Larger