Week 9 - Study Guide Flashcards
Definition of Cardiac Output
blood pumped by the ventricle in one minute (minute volume)
Formula for Cardiac Output
CO = (SV)(HR)
(ml/min) = (ml/beat)(bpm)
Average heart rate
75 bpm
Stroke Volume is
amount of blood pumped by each ventricle with each heart beat
Stroke Volume =
average 70 ml/beats
what is the AVG CO =
5.35 L/min
for every minute = is nearly the entire blood volume of the body
Total Blood volume =
5.5 L
Each ventricle pumps equivalent of total blood volume/minute at rest
Cardiac Reserve =
difference between CO at rest and all-out work
which is allowing us to understand that there is a normal resting cardiacoutput
AND
a large reserve capacity allowing us to increase our activity quite a bit
Exercise CO =
14-20 L/min
Hemorrhage CO =
1.5 L/min
Elite Athletes CO =
30 L/min
Contraction phase
Systole
pumped volume
Relaxation phase
Diastole
filled volume
Formula for Stroke Volume (SV) =
SV = EDV - ESV
when ventricles are full = EDV
when ventricles pump = ESV
SV is the difference
Dicrotic Notch
closure of the aortic semilunar valve causes temporary increase pressure
blood briefly backflow against the valve.
Which contraction is the biggest pressure change?
Left ventricular contraction
which alters Left atria and aortic pressure
Frank-Starling Law
Better fill = Better pumping
Amount of stretching in ventricle prior to contraction
Factors affecting stroke volume
- Frank-Starling Law
- Sympathetic nerve activity
- Venous return (determines and influences the EDV)
What do you want in cardiac muscle in regards to sarcomere length?
Want the most stretching, the greatest filling that you can - in order to create the greatest pumping efficiency
The more you stretch - the better the contractile strength.
Preload
filling or stretching of the ventricles - creating the strength of their contractions
for heart to be effective, preload has to be greater than afterload