| Question |
 |
|
| Answer |
|
|
| Cardiac Output |
volume of blood pumped by each ventricle per minute |
| Stroke Volume |
Volume of blood ejected per beat |
| Heart Rate |
Number of heart beats/minute |
| Cardiac Output Equation |
CO = HR x SV |
| Stroke Volume Equation |
SV = EDV - ESV |
| Schematic for the SV component of the Equation |
Preload (Starling Effect)
Contractility
Afterload
Compliance |
| Ejection Fraction |
EF = (SV)/(EDV) |
| Inotropy |
contractility |
| Starlings Law |
As volume increases, length increases and the greater the contraction |
| Compliance Equation |
(delta)V/(delta)P |
| Increasing Preload causes |
Increasing EDP
Increasing EDV
Increases SV and CO |
| Decreased HR causes |
less time for filling and results in a lesser force |
| Afterload |
force it has to overcome (arterial pressure) |
| Increasing Afterload |
Increases pre-ejection pressure
Increases ESV
Decreases SV and CO |
| Increasing contractility |
Decreases ESV
Increases SV |
| Lowering Compliance |
decreased EDV
Decreases SV and CO |
| length affects |
tension and velocity |
| Ejection Fraction in normal health |
55% |
| What is the only way to change the slope of the left ventricular pressure |
change contractility |
| What affects contractility? (3) |
Positive inotropic effects
|
| Postive inotropes caused by |
open Ca channels
inhibition of the Na/Ca exchanger
Inhibit plasma membrane pump
Activations of B1 receptors |
| what cardiac drug induces positive inotropic effects? |
Cardiac glycosides (digitalis) |
| Negative inotropes |
Ca channel blockers
Low Ca
High extracellular Na |
| Determinants of O2 demand on the heart |
afterload
extent of muscle shortening
heart rate
inotropic state
heart size |
| 60-90% of cardiac ATP derived from ________ |
free fatty acids |
| Calculating CO using the Fick Principle: |
"oxygen is the indicator" |
| Cardiac Output equation using Fick Principle |
CO = O2 consumption / (O2 pulmonary vein - )2 pulmonary artery) |
HHS Shrek
