Lec 22 Cardiovascular Part 2 Flashcards
Arteries establish what
Bulk flow and driving pressure
Without the means of direction
Arterioles establish what
Regulation of flow to specific regions
Capillaries establish what
Are the ONLY sites for gas exchange with tissues
Veins and venules establish what
Regulate flow return
What are the contributions of sympathetic and parasympathetic NS in relation to rest to exercise
Rest
Parasympathetic contribution is high and sympathetic is low
Max intensity
Sympathetic contribution is high and parasympathetic is low
What is stroke volume
How is it measured
The volume of blood ejected during one heart beat
The difference in ventricular volume at the end of diastole and end of systole
SV = EDV - ESV
What is ejection fraction
How is it measured
Is the fraction in a percentage of blood pumped out of the left ventricle relative to the total volume of left ventricle
EF = SV/EDV
Compare trained to non trained
Ejection fraction, how much blood goes in and out of the heart, EDV, SV
Ejection fraction stays the same
How much blood goes in and out is different
EDV and SV is different
What is cardiac output (Q)
How is it measured
Is the amount of blood pumped by the heart in one minute
= SV x HR
In relation to cardiac output what happens in one minute
Approximately all your blood is pumped throughout the body - 5L
Compare trained and untrained
HR and stroke volume
Untrained will have a higher heart rate and a lower stroke volume
Trained will have a higher stroke volume but lower heart rate
What is the definition of the Fick equation
How is it measured
Oxygen uptake is equal to the product of cardiac output and oxygen extraction
Q x avo2 difference
Avo2 difference _______ with intensity
What happens to Cao2 and Cvo2
What is caused
Increases
Cao2 (arterial) stays at a steady state - increased ventilation ensures nearly complete arterial saturation
Cvo2 (venous) declines - more o2 stakes up by the muscles
A greater avo2 difference
What stays the same during increasing intensity exercise and what changes
Arterial o2 content stays the same
Venous o2 content decreases
HR ___________ ____________ with intensity
What are the intrinsic and extrinsic regulation factors
Increases linearly
Intrinsic - heart maintains it own rhythm (~100bpm) — Sa node - av node - av bundle - ventricles
Extrinsic - adjust HR (~25-200bpm)
- parasympathetic, sympathetic, central command, endocrine, peripheral input ( mechanical - muscles, vasculature) and (chemical - group III/IV metabolites )
What happens to stroke volume with in increase in intensity
During submaximal exercise Q and HR increase linearly with progressive increase in intensity HOWEVER, SV has an initial increase followed by small changes/plateau at around 30-50% of vo2max
What two factors impact EDV
What two factors impact ESV
Venous return and ventricular distensibility
Ventricular contractility and aortic (or pulmonary artery) pressure
What factor plateaus during exercise
Stroke volume
What three factors impact venous return
Muscle pump
Respiratory pump
Valves located in veins
During prolonged constant intensity exercise, there is a gradual decrease in SV due to ________,__________,________
This results in a _________ in HR
Water loss, fluid shifts, and blood flow redistribution
An increase
Why does cardiac output increase during exercise? Stroke volume or HR
hR
What plateaus faster ? Stroke volume or cardiac output
SV
What is the frank-starling law of the heart
Stretching ventricles increases force of contraction
A greater EDV yields a greater SV within physiological limits
