Clin Phys Week 7 E Flashcards
What is the function of the heart
Deliver nutrients to the cells
Deliver waste to the excretory organs
What are the chordae tendineae?
A cord which the AV valves to papillary muscles on the ventricular floor.
Describe semilunar valve function
As the ventricles contact and inter ventricular pressure rises, blood is pushed up against the semilunar valves, forcing them to open. As the ventricles relax and inter ventricular pressure drops, blood flows back from the arteries, filling the cusps of the semilunar valves and forcing them to close to prevent further back flow.
What is systole?
Contraction / ejection of blood
What is diastole?
Relaxation / filling
What is typical end diastolic volume?
approx 130 mls
What is typical stroke volume?
approx 70 mls
What is end systolic volume?
The amount left in heart after ventricular contraction.
What are the heart valves made of?
Doubled over endocardium
What is the systolic and end diastolic range of the left ventricle?
Systolic: 90-140mm Hg
End diastolic: 4-12mm Hg
What is the systolic and end diastolic range of the right ventricle?
Systolic: 15-28mm Hg
End diastolic: 0-8mm Hg
What is the systolic range for the aorta?
96-140mm Hg
What is the diastolic range for the aorta?
60-90mm Hg
What does the heart sound S1 represent?
It indicates the beginning of systole and is heard as a “LUBB” sound. Best heart at the apex and is generally the loudest heart sound.
What does the heart sound S2 represent?
It represents the end of systole and is heard as a “DUBB” sound.
How many heart sound contribute to the S2? if more than one, what are they?
2 = A2 and P2
A2 = aortic valve closing
P2 = pulmonary valve closing.
Under what circumstances is the P2 sound occurring later than the A2 sound?
During inspiration (the venous return from the lungs is reduced as there is more space in the lung cavity so the pressure on the pulmonary semilunar valve is slightly less than the aorta, so it closes slightly later)