Regulation of Cardiac Function Flashcards
What happens during diastole in the heart?
Passive filling (from vena cava and pulmonary vein)
AV valves open
Pulmonary and aortic valves closed
Pressure is consistent between the atria and the ventricle
What happens to the heart during atria systole?
The AV valves are open
Aortic and pulmonary valves are shut
Last of the blood is ejected from the atria into the ventricles
What happens during isovolumetric contraction?
Both the AV and SL valves are closed.
No blood flow, isovolumetric contraction of the ventricles occurs during ventricular systole.
No change in ventricular volume but as the pressure begins to increase, the AV valves close.
Ventricular pressure increases dramatically.
What happens during ejection?
The AV valves and the SL valves are open. Rapid outflow of blood into the aorta and the pulmonary artery.
Ventricular pressure exceeds that of the aorta and pulmonary artery.
After a contraction, what happens in isovolumetric relaxation?
AV and SL valves shut. Ejection slows as ventricular contraction loses force. Brief backflow prevented by AV valve closing. One below the pressure of the outflow vessels, the aortic and pulmonary valves close to prevent backflow.
Ventricles undergo isovolumetric relaxation, rapidly decreasing pressure.
What is the time length for a cardiac cycle?
500msec
What causes the ventricles to mainly fill themselves once the mitral valve opens?
Elastic recoil of the ventricle
What is the dicrotic notch in the cardiac cycle caused by?
The aortic valve closing
What is the LVEDV?
What is LVESV?
What is the difference between them called?
Left ventricular end diastolic volume
Left ventricular end systolic volume
Stroke volume
What is the P wave?
What is the QRS complex?
What is the T wave?
P wave - atrial depolarisation
QRS - complex due to ventricular depolarisation
T wave - ventricular repolarisation
There are 4 sounds during heart contraction, lub-dub and 2 more noises. What are they due to?
S1 - initiation of V systole (lub sound)
S2 - closure of SL valves (dub sound)
S3 - opening of AV valves and rapid refilling
S4 - Atrial systole: rarely heard unless end diastolic pressure is raised
What is a murmur and what causes it?
It is a turbulence in the blood.
It is caused by increased blood velocity.
What is stenosis and what two murmurs does it cause?
It is the narrowing of blood vessels.
Mitral Stenosis - diastolic murmur as ventricle fills
Aortic stenosis - systolic murmur (high pressure)
What is valve incompetence and what two murmurs can it form?
It is leakage (backflow).
Mitral incompetence - a systolic murmur
Aortic incompetence - early diastolic murmur
What is a sign of valve incompetence and how do we test for it?
Pulsing veins (seen in the neck). A pulsating vein would stop pulsing if a patient sits up,. If it persists, then the pulsating may be in the carotid artery.
