week 13

Question 1

factors that influence EDV/preload

Answer 1

venous return
skeletal muscle pump
filling time
venous tone
venous BP
blood volume

Question 2

factors that influence afterload

Answer 2

arterial BP
vasodilation/constriction
vascular resistance

Question 3

factors that influence contraction force

Answer 3

preload
contractility

Question 4

during extended heavy exercise, cardiac output remains stable but…

Answer 4

HR increases and SV decreases

Question 5

how does decreased blood volume lead to decreased stroke volume?

Answer 5

1. decreased blood volume leads to decreased venous return
   
   • decreased prelaod/decreased EDV
     
     • decreased SV beause less blood in the heart before contraction
   • decreased contraction force
     
     • lower SV bc less of the blood that is in the ventricle gets squeezed out
2. decreased blood volume leads to lower mean arterial pressure
   
   • lower afterload
     
     • increased SV bc the heart needs to overcome less force to eject blood

overall: the effect of lower venous return outweighs the effect of lower MAP and SV drops

Question 6

if lower blood volume leads to decreased SV, what would happen to HR?

Answer 6

HR increases in order to keep Q constant

Question 7

copy down second slide on page 5 of CVII

Question 8

review first slide on page 6 of CVII

Question 9

how do we mitigate cardiovascular drift and its functional consequences?

Answer 9

stay hydrated and cool

Question 10

write down page 7 of CVII

Question 11

what happens in acute exercise?

Answer 11

1. numerous changes (increased mvmt, emotions, body temp, local metabolites, etc…) are detected by receptors throughout the body and are communicated to the cardiovascular control center in the medulla
2. the cardiovascular control center integrates the inputs and responds by reducing in PSNS outflow to the SA node via the vagus nerve. if needed, SNS outflow to the SA node via the accelerator nerve will also be increased
3. the result is an increase in HR up to HRmax at max SNS stimulation

Question 12

what are some cardiovascular challenges of exercise?

Answer 12

• we need to pump a lot more blood per minute
• we need to direct blood flow to the right places

Question 13

copy down second slide on page 9 of CVII

Question 14

will MAP always be closer to or further from DBP than SBP

Answer 14

MAP will always be closer to DBP than to SBP

Question 15

diastolic vs systolic BP

Answer 15

diastolic BP: intra-arterial pressure during ventricular relaxation

systolic BP: intra-arterial pressure during ventricular contraction

Question 16

what do SBP and HR influence?

Answer 16

SBP (force of contractions) and HR (how many contractions) influence myocardial work and myocardial VO2

Question 17

what is the formula for rate pressure product (RPP)

Answer 17

RPP provides an estimate of myocardial work aka “strain on heart”

rate pressure product (RPP) = SBP x HR / 100

Question 18

how do we selectively vasodilate/vasoconstrict different vessels?

Answer 18

smooth muscle in arterioles is regulated via:
- autonomic nervous system control (dilation/constriction in response to SNS/PSNS innervation)
- hormonal control (constriction in response to epinephrine/norepinephrine)
- intrinsic metabolic control (dilation/constriction in response to local metabolic activity)

Question 19

copy down page 12 of CVII

Question 20

how do patterns of blood flow distribution change during exercise?

Answer 20

• increased O2 delivery to skeletal muscle, heart and brain
• decreased O2 delivery to viscera
• increased blood flow to skin at lower intensities (to help thermoregulate) but skeletal muscle takes priority at max exercise so blood flow to skin decreases

Question 21

review page 14 of CVII

Question 22

acute vs. chronic responses to exercise

Answer 22

acute responses: how the body responds to a single bout of exercise

chronic: how the body changes in response to chronic (repeated) exposure to exercise - training adaptations

Question 23

what are the 5 training principles

Answer 23

1. overload
2. progression
3. individual differences
4. reversibility
5. specificity

Question 24

aerobic exercise imposes a high ___ on the heart and resistance exercise imposes a high ___ on the heart

Answer 24

volume load

pressure load

Question 25

why do endurance athletes have bradycardia (low HR) at rest?

Answer 25

• cardiac adaptations + increased blood volume = increased SV
• can achieve the same Q with lower HR