Cardiac A&P Flashcards
What is the function of the valves of the heart?
To control the flow of blood between chambers and into the great vessels
When do the mitral and tricuspid valves close?
During Ventricular systole
What are the two branches of the Left Main Coronary artery?
The Left Anterior descending and the circumflex arteries
What are the three branches of the Left anterior Descending artery
Ramus, Diagonals, Septals
The circumflex artery ecentually becomes the ___
Obtuse Marginals
What is Automaticity?
The ability of the cardiac cells to initiate an electrical stimulus
What is Excitability
The ability of the myocardial cells to respond to a stimulus
What is conductivity
The ability to transmit the impulse from one cell to another
what is contractility?
The ability of myocardial cells to shorten (contract) in response to an electrical stimulus
What is refractoriness?
The inability of cells to respond to an electrical impulse if they have not recovered from the previous episode.
What are the two refractory periods?
The absolute and the relative
WHat is the absolute refractory period?
The period of time when the heart will not respond to stimuli of any magnitude
What is the relative refractory period?
The heart can still respond to a strong stimuli
What is stroke Volume?
The amount of blood ejected with each contraction of the LV
WHat is heart rate?
The number of times the ventricles contract in one minute
What is cardiac output?
The volume of blood pumped in one minute
What is the normal range for Cardiac output?
4-7 Liters per minute
How is Cardiac Output calculated?
Stroke volume X Heart rate
CO= SV X HR
WHat is the Cardiac index?
An asjustment made to the CO based on the body size in terms of BSA
What is the normal range for Cardiac INdex?
2.7-3.2 L/min/M sq
Why is Cardiac Index important?
Because it takes body size into account when calculating Cardiac Output Needs. An obese Person will need more CO to supply their tissues so a normal CO value may still be inadequate for them
How is Cardiac Index calculated?
CI= CO/BSA
What is preload?
The amount of myocardial stretch at the end of the diastole.
What determines the Pre-load?
The Left Ventricular End Diastolic Volume (LVEDV)
Preload is tied to what law
Starlings Law