Chapter 5- Basic Cardiac Cycle Flashcards
When the QRS complex begins, is it almost immediately followed by an increase or a decrease in ventricular pressure ?
An Increase in ventricular pressure
The P wave is followed very closely by changes in pressure in the atria, is it called atrial systole or atrial diastole and how pressure changes ?
It is called atrial systole, which is increased pressure in the atria corresponding to atrial contraction
How is the ventricular contraction phase called?
The ventricular systole
What happens when ventricular pressure increase above atrial pressure ?
The AV valves close
When left ventricular pressure increases above aortic pressure what happens?
The SL aortic valve opens
What happens when the pressure in the left ventricle becomes less than the aortic pressure ?
The aortic SL valve closes, preventing the back flow of the blood in the left ventricle
What happens when the ventricular pressure falls below the atrial pressure ?
The AV valves open, then the ventricles start to fill with blood again
When the atria contract they do push more blood in ventricles increasing the intraventricular volumes slightly or tremendously ?
During atrial systole, the ventricular volume increase slightly
When ventricles contract what happen to ventricular volumes ?
Ventricular volumes decrease
Ventricles are filling with blood during ventricular diastole or systole ?
During ventricular diastole
Hear sound 1 is caused by what event ?
When AV valves close
Heart sound 2 is caused by what event ?
When SL valves close
Hear sound 1 indicates the beginning of which phase?
Ventricular systole
Heart sound 2 indicates the beginning of which phase ?
Ventricular diastole
What defines the cardiac output ?
The cardiac output is the volume of blood ejected from a ventricle per minute
What factors determine cardiac output ?
Heart rate and volume of blood ejected by the heart = stroke volume
Cardiac output = heart rate x stroke volume
What means EDV ?
End diastolic volume, which is the volume in the ventricle at the end of ventricular diastole, the highest volume of blood in the ventricle
What means ESV ?
End systolic volume, which is the volume in the ventricle at the end of ventricular systole, the lowest volume of blood in the ventricle
What means SV?
Stroke volume, which is the volume of blood ejected during a single heart beat
SV = EDV - ESV
What is the autonomic nervous system ?
The sympathetic nervous system and the parasympathetic nervous system
What are the consequences of the sympathetic nervous system action on the heart ?
Increase heart rate ( tachycardia) and force of contraction
What are the consequences of parasympathetic nervous system action on the heart ?
Decrease heart rate ( bradycardia via the vagus nerves)
