Cardiovascular System - Lecture 10

Question 1

What happens to the cardiovascular effects of exercise? (2)

Answer 1

1. sustained (steady state)
2. O2 used = O2 taken in

Question 2

What happens to HR during exercise?

Answer 2

it increases

Question 3

HR during exercise is proportional to what?

Answer 3

work

Question 4

How can you find your Max HR?

Answer 4

220-age (variable) and decreases as a function of your age

Question 5

How much can your HR change during exercise?

Answer 5

3x or more (60 to 180 BPM)

Question 6

Why does HR increase during exercise?

Answer 6

due to increase in sympathetic tone and decrease in parasympathetic tone

Question 7

What happens to stroke volume during exercise?

Answer 7

it increases a little (in the situation in the notes, it dips)

Question 8

What increases contractility in stroke volume during exercise?

Answer 8

sympathetic activity

Question 9

At very high heart rates there is usually a ___ in SV.

Answer 9

fall

Question 10

Why is there a fall in SV at very high heart rates?

Answer 10

• decrease systole
• diastolic period shortens much more
• filling time decreases

Question 11

What happens to cardiac output during exercise?

Answer 11

it goes up linearly

Question 12

What does CO mostly depend on during exercise?

Answer 12

HR

Question 13

What is the factor for both HR and CO?

Answer 13

3

Question 14

What does circulating epinephrine bind to on the SA node to increase HR and contractility?

Answer 14

b-receptors

Question 15

What happens to MAP during exercise?

Answer 15

it increases a bit (20%)

Question 16

What is the factor of increase in MAP compared to CO?

Answer 16

1.2 compared to 3

Question 17

What happens to diastolic AP during exercise?

Answer 17

almost no increase

Question 18

What happens to systole AP during exercise?

Answer 18

increases from 120 to 190

Question 19

What do you check during the cardiac ‘stress test’?

Answer 19

make sure the systolic rises to a high level (around 200 mmHg)
- measures the ventricles ability to generate force

Question 20

What does low force during cardiac stress test indicate?

Answer 20

damage to ventricles (scar tissue)

Question 21

What happens to TPR during exercise?

Answer 21

it drops 40% its resting value

Question 22

Why does TPR drop during exercise?

Answer 22

because muscles consume more O2 and generate waste products: metabolic autoregulation

Question 23

What happens to oxygen consumption during exercise?

Answer 23

it rises by around 9x

Question 24

Why does oxygen consumption increase by 9x?

Answer 24

Oxygen consumption increase due to 3x increase in CO and a 3x increase in the amount of O2 extracted (3x arteriovenous O2 difference).

Question 25

What is the ranking of increased blood flow during exercise?

Answer 25

1. muscle 2. skin 3. heart 4. elsewhere

Question 26

What factor does blood flow increase in muscle during exercise?

Answer 26

12x

Question 27

What factor does blood flow increase in skin during exercise?

Answer 27

5x

Question 28

What factor does blood flow increase in the heart during exercise?

Answer 28

3.5x

Question 29

Why is there a drop in the rest of the body during exercise?

Answer 29

because MAP is almost constant which compensates for increase

Question 30

Norepinephrine is a potent ___ agonist.

Answer 30

alpha

Question 31

Epinephrine is a ___ agonist.

Answer 31

beta

Question 32

What receptor activation balance determines tone at rest?

Answer 32

alpha beta receptor activation

Question 33

What happens in non-exercising muscle and most organs during exercise?

Answer 33

1. alpha>>beta = constriction 2. R increases

Question 34

T or F: Non-exercise muscle does experience vasoconstriction in arterioles during exercise.

Answer 34

true

Question 35

What 3 substances increases vasoconstriction in alpha receptors?

Answer 35

plasma norepinephrine, norepinephrine in ECF, plasma epinephrine

Question 36

Which receptor causes vasoconstriction?

Answer 36

alpha

Question 37

Which substance increases vasodilation in beta receptors?

Answer 37

plasma epinephrine

Question 38

T or F: Training has an effect on max heart rate.

Answer 38

false, it has no effect on max heart rate

Question 39

What happens to stroke volume and heart rate during a few weeks of aerobic training?

Answer 39

SV: increases HR: doesnt increase

Question 40

What happens to contractility during endurance training?

Answer 40

it increases

Question 41

What happens to hypertrophy, SV and resting HR during endurance training when contractility increases?

Answer 41

hypertrophy: increases SV: increases resting HR: falls