Heart As a Pump Flashcards
What is the only artery that carries deoxygenated blood?
Pulmonary artery
What is the valve between the right atrium and right ventricle?
Tricuspid valve
What is the valve between the left atrium and left ventricle?
Mitral valve
How many mls of blood are approximately in each chamber/cycle?
60 mls
Calculate stroke volume if the HR is 80 bpm
80 x 60 mls of blood = 4,800 mls of cardiac output
Which node is the pacemaker node?
Sino-Atrial
T/F the Parasympathetic system affects the cardiac muscles in order to affect HR
False, it affects the electrical firing
In a normal cardiac cycle, how does contraction in relation to the atriums and ventricles occur?
2 atria contract together while the 2 ventricles are relaxed; and viceversa
If there is a contraction of a chamber, it is termed:
Systole
Describe Diastole
The relaxation of any chamber
Describe pressure differences in the chambers while they are in systole or diastole
Pressure rises in contraction (systole) and drops in diastole
Where does the LA receive oxygenated blood from?
Pulmonary Veins
Another name for the mitral valve?
left atrioventricular valve
What is another name for the valve that prevents blood from returning into the Left Ventricle?
Aortic Valve/Left AV
Which part of the heart receives deoxygenated blood?
Right atrium
Where does the right ventricle eject blood into?
Pulmonary artery
Which valve prevents blood from returning into the right atrium?
Tricuspid (R AV)
Describe the function of the pulmonic valve
allow blood to flow from RV to Pulm a; prevent blood from returning into right ventricle
Ventricular _______ is ventricular relaxation/filling
diastole
Ventricular _____________ is ventricular contraction/ejection
systole
What follows electrical stimulation?
Mechanical contraction
Atrial Systole follows depolarization of what?
Atrial myocytes
Which wave on an ECG is Atrial systole?
P wave
What follows the depolarization of the ventricular myocytes?
Ventricular systole
Which wave is ventricular systole in the ECG?
QRS
List the 3 steps of the electrical impulse through the heart
- AV node
- Bundle of His
- Purkinje fibers
What is it called when pressure increases but volume is unchanged?
Isovolumic contraction
When do atrioventricular valves close?
When ventricular pressure exceeds atrial pressure
What happens when pressure in the ventricles exceeds pressure in large vessels?
Aortic and pulmonic valves open and ventricles eject blood
What is it called when pressure decreases but volume doesn’t change?
Isovolumic relaxation
Between the T and P waves, what is happening?
Ventricular cells are at rest
What wave stimulates the atria?
P wave
In the ejection phase, volume (increases/decreases)
Decreases
What happens to pressure during the ejection phase?
Increases then decreases
In what phase of Systole does the volume remain constant?
Isovolumic contraction
The 2 phases of the systole are:
Isovolumic contraction and ejection phase
List the 4 phases of the diastole
-isovolumic relaxation
- rapid ventricle filling
- slow ventricle filling
- atrial contraction
What is the term for the slow filling of the ventricles?
Diastasis
What marks the beginning of systole?
Closure of AV valves
What marks the beginning of diastole?
Closure of Semilunar valves
The ventricle generates enough pressure to equal that of the vessels during what phase of the cardiac cycle?
Systole
In diastole, describe pressure in the ventricles
it decreases until it is below atrial pressure
Which side of circulation is “high” pressured ?
Left
T/F: Since right side circulation is low pressured, Pulmonary artery pressure can fall to 0 at some point in the cycle
FALSE
When is pressure equal in the atria and the ventricles?
When the AV valves open
Ventricular pressure= arterial pressure when which valves open?
Semilunar
What is the end-systolic volume ?
~30 mls (ventricles dont empty completely)
End diastolic - end-systolic volume = ?
Stroke volume
If The end-diastolic volume is 72 mls and end-systolic is 35, what is the stroke volume?
37 mls
