HRR: Cardiodynamics I Flashcards
What initiates the electrical activation of the heart?
The SA node
The SA node is known as the natural pacemaker of the heart.
What occurs after the impulse spreads to the AV node?
The impulse waits, generating the PR segment
This delay allows the atria to fully depolarize and contract before the ventricles.
What does the QRS complex represent?
Depolarization of the ventricles
The QRS complex is typically narrow in healthy individuals.
What is the first area to depolarize in the ventricles?
Endocardium and papillary muscles
This helps the chordae tendineae maintain valve closure during pressure changes.
Which heart chambers are significant when referring to systole and diastole?
Ventricles
Systole refers to contraction, while diastole refers to relaxation.
How is blood flow from the vena cava and pulmonary veins characterized?
Continuous
There is no pulsatility associated with this flow.
What is end diastolic volume?
The volume in the ventricle just before contraction
This is the maximum volume of blood in the ventricle during the cardiac cycle.
What is end systolic volume?
The volume in the ventricle just after contraction
This represents the minimum volume of blood remaining in the ventricle.
Define stroke volume.
The amount of blood ejected in one cycle
Stroke volume is a key indicator of heart function.
What is the ejection fraction?
The percentage of blood emptied during a beat
Ejection fraction is an important measure of cardiac efficiency.
How do valves in the heart work?
They rely on pressure differences
Valves open when proximal pressure exceeds distal pressure.
Where is resistance higher when a valve is closed?
Proximal side
This is due to the pressure differential across the valve.
What is the typical pressure in the right atrium?
4 mmHg
This pressure is crucial for understanding cardiac function.
What is the typical pressure in the right atrium?
4 mmHg
The right atrium typically experiences low pressure compared to other chambers of the heart.
What is the typical pressure in the right ventricle?
21/4 mmHg
The right ventricle has a low pressure compared to the left ventricle, as it pumps blood to the lungs.
What is the trial pressure in the pulmonary artery?
21/10 mmHg
This pressure reflects the resistance the right ventricle faces when pumping blood into the pulmonary circulation.
What is the typical pressure in the left ventricle?
120/8 mmHg
The left ventricle generates higher pressure to pump blood into the systemic circulation.
What is the typical pressure in the aorta?
120/80 mmHg
This pressure represents the systolic and diastolic pressures in the aorta during the cardiac cycle.
What does the Wiggers diagram represent?
The relationship between cardiac pressures, volumes, and ECG waveforms
It illustrates the phases of the cardiac cycle and the corresponding pressures in different heart chambers.
Fill in the blank: The pressure in the right atrium is typically _____ mmHg.
8
Fill in the blank: The pressure in the aorta is typically _____ mmHg.
120/80
True or False: The pressure in the left ventricle is lower than in the right ventricle.
False
The left ventricle has a much higher pressure due to its role in systemic circulation.
What is the significance of the pressure in the pulmonary artery?
It indicates the pressure the right ventricle must overcome to pump blood to the lungs
Elevated pressures in the pulmonary artery can indicate pulmonary hypertension.
What is the normal pressure range in the right ventricle?
21/4 mmHg
This low pressure is necessary for the function of the right ventricle as it pumps blood into the pulmonary artery.
