Lecture 10 Flashcards
What do the heart sounds represent?
first valve sound comes from systole where the atrioventricular valves close.
second heart sound occurs during diastole.
What are the kinds of problems associated with valves?
2 kinds of valve problems:
Stenosis: restricted valve opening causing reduced flow and higher pressure gradient. Upstream chamber is where the blood comes from. Pressure load needs to be overcome and this causes concentric hypertrophy (more pressure required from bigger walls).
Incompetence: Imperfect closure causes a reduced forward flow due to leaking back of the blood through the valve (regurgitation) upstream chamber ends up having an increase in volume. This is due to the chamber upstream having to operate at higher volumes.
What is turbulence in relation to blood flow?
Incompetence in valves causes turbulence in blood flow due to disruption in lamina flow. Turbulence results in heart murmors and this can be heard with a stethoscope.
When can turbulence occur if the valves are not incompetent?
When the heart blood flow is higher than required.
This is the case in children, during fevers, and anemia.
What does exercise do to people with heart valve murmours?
Exercise can exacerbate the difficulties associated with valve dysfunction in people with valve lesions. This is because exercise increases the demands more cardiac output. This can be used to diagnose a valve problem.
How long do physiological changes take to manifest in people with valve dysfunction?
physiological changes associated with valve dysfunction depends on the rapidity of its onset.
What is the result of some heart attacks on valves?
heart attacks can cause lack of blood to the papillary muscles and their death results in the breaking off of the chordae tendinae which causes backflow of blood.
What is the result of aortic regurgitation?
Aortic regurgitation causes blood to fall back into the LV during diastole causing overload of LV and its eventual hypertrophy.
What kind of hypertrophy affects people with aortic regurgitation?
Eccentric hypertrophy; this is to accomodate a greater amount of blood and to be able to push it.
What is the effect of aortic regurgitation on cardiac output?
stroke volume and pulse pressure increases as a result of aortic regurgitation.
What is the result of a bad left atrioventricular valve?
mitral regurgitation causes less blood entering aorta and instead blood enters atrium and the aorta. As a result LV gets higher blood volume.
Hypertrophy is seen in both the left atrium and left ventricle.
What is the result of mitral stenosis?
Mitral stenosis causes increase in left atrial pressure which results in concentric hypertrophy of the left atrium.
