HBIO 320 EXAM 2 - MUSCLE BLOOD FLOW EXAM QUESTIONS
AND ANSWERS WITH COMPLETE SOLUTIONS GRADED A++
What are the components of Cardiac output?
CO = heart rate X stroke volume
- Lungs will never be a limiting factor to VO2 max
How can stroke volume be modulated?
- Contraction strength
- End-diastolic volume (preload)
- Afterload (mean arterial pressure): how much of contraction pressure is solely devoted
to opening aortic valve
How can contractility of the heart be increased?
- Increased SNS activity: Increases cystolic calcium, causing greater contraction
- Stretch: frank-starling mechanism
What is the Frank-Starling mechanism?
- Greater preload -> greater contraction/stroke volume
- Cardiac muscle is stiffer than skeletal muscle (always shorter than optimal range)
- Stretch -> increase passive and active tension
How can preload be increased?
- Venoconstriction
- skeletal muscle pump: Contraction of leg muscles to push blood back up towards heart
AND ANSWERS WITH COMPLETE SOLUTIONS GRADED A++
What are the components of Cardiac output?
CO = heart rate X stroke volume
- Lungs will never be a limiting factor to VO2 max
How can stroke volume be modulated?
- Contraction strength
- End-diastolic volume (preload)
- Afterload (mean arterial pressure): how much of contraction pressure is solely devoted
to opening aortic valve
How can contractility of the heart be increased?
- Increased SNS activity: Increases cystolic calcium, causing greater contraction
- Stretch: frank-starling mechanism
What is the Frank-Starling mechanism?
- Greater preload -> greater contraction/stroke volume
- Cardiac muscle is stiffer than skeletal muscle (always shorter than optimal range)
- Stretch -> increase passive and active tension
How can preload be increased?
- Venoconstriction
- skeletal muscle pump: Contraction of leg muscles to push blood back up towards heart
