MSF Questions and Answers

MSF Questions and
Answers


Mean Aortic Pressure


Ans- 100 mmHg




Mean Ateriole Pressure


Ans- 50 mmHg




Mean Capillary Pressure


Ans- 20 mmHg




Mean Vena Cava Pressure


Ans- 5 mmHg

,What is the most important determinant of pulse pressure?


Ans- Stroke volume




What does pulmonary wedge pressure measure?


Ans- the smallest artery in the pulmonary system - so essentially pulmonary

capillary pressure, which is approximately equal to left atrial pressure




Stimulation by the parasympathetic nervous system would cause a(n) _____ in

the PR interval.


Ans- Increase




What phase of an action potential is caused by a brief repolarization, and what

electrolytes are responsible?


Ans- 1; in part due to K+ outward current and in part by lack of Na+

conductance




What electrolyte is responsible for the upstroke of the SA action potential?


Ans- influx of Ca++

, Chronotropic effects produce a change in what?


Ans- Heart Rate, by increasing or decreasing firing rate of SA node




Dromotrophic effects produce a change in what?


Ans- Change in conduction velocity primarily through the AV node




What effect do cardiac glycosides have on intracellular Ca++ levels?


Ans- Ca++ levels increase intracellularly




Preload!


Ans- End-diastolic volume - related to right atrial pressure; increases with

increased venous return.




Afterload!


Ans- Aortic Pressure