8. Heart 1 Flashcards
What is the number 1 worldwide cause of mortality, causing 1/3 of deaths in the US?
Cardiovascular disease (CAD, stroke, peripheral vascular dz)
The heart should weight approx 0.4-0.5% of the body. 250-320gm for females and 300-360gm for males. What are the right and left ventricle normal thicknesses?
Left ventricle 1.3-1.5cm
Right ventricle 0.3-0.5cm
Hypertrophy of the heart is when there is an increase in ventricular thickness, cardiomegaly is when there is an increase in cardiac weight and dilation means?
enlarged chamber size
Atrial myocytes have storage granules that contain atrial natriuretic peptide which promotes arterial vasodilation and stimulates what, which is beneficial in HTN and CHF?
renal salt and water elimnation (natriuresis and diuresis)
Pathologic changes of valves are largely of 3 types… damage to collagen that weakens leaflets as seen in mitral prolapse, nodular calcification in interstitial cells as in calcific aortic stenosis (NOTCH 1) and?
fibrotic thickening as seen in rheumatic heart dz
SA node is the pacemaker of the heart and the AV node is the gatekeeper of the heart which ensures?
that atrial contraction precedes ventricular systole
LAD has diagnol branches and left circumflex A has marginal branches. When do the coronary arteries get their blood?
during ventricular diastole when the aortic valve closes, allowing blood flow to myocardium
The cardiac stem cells are bone marrow derived precursors and stem cells present in the myocardium. Do the cells get replaced often?
NO! only 1% each year, so not able to recover from damage like other areas in the body
As the heart ages the LV cavity/volume decreases while the walls thicken and there is an increase in epicardial fat, what can be seen histologically? 2
Lipofuscin and basophilic degeneration
With age, aortic and mitral valves build annular calcification and fibrous thickening occurs. Mitral leaflets may buckle leading to what?
increase in left atrium size (d/t increased volume)
what are small filiform processes that form on the closure lines of aortic and mitral valves probably resulting from the organization of small thrombi?
Lambl Excrescences
What occurs when the myocardium contracts weakly during systole and there is inadequate cardiac output OR myocardium may relax insufficiently during diastole to permit adequate ventricular filling?
Pump failure
Another cardiac pathophysiology mechanism that can occur are lesions can obstruct blood flow through a vessel or prevent valve opening or otherwise increased ventricular chamber pressure… known as?
flow obstruction
What occurs when a portion of the output from each contraction flows backward through an incompetent valve, adding a volume overload to the affected atria or ventricles?
Regurgitation flow
What occurs when blood is diverted from one part of the heart to another thorugh defects that can be congenital or acquired?
Shunted flow
What is the most common cardiac pathophys when conduction defects or arrhythmias due to uncoordinated generation or transmission of impulses lead to nonuniform and inefficient myocardial contrations - fatal?
disorders of cardiac confuction
What occurs in situations there is cataclysmic exsanguination either into body cavities or externally?
rupture of the heart or a major vessel
What occurs when the heart is unable to pump blood at a rate to meet peripheral demand or can only do so with increased filling pressure?
Congestive heart failure CHF
CHF may results from loss of myocardial contractile function (systolic dysfunction) or from loss of ability to?
fill the ventricles during diastole (diastole dysfunction
Cardiac myocytes become hypertrophic when there is sustained pressure or volume overload due to systemic HTN or aortic stenosis or when there is sustained?
trophic signals such as B-adrenergic stimulation
In the setting of pressure overload hypertrophy, the myocytes become thicker and?
the left ventricle increases thickness concentrically (cause need stronger contraction to beat high pressure)
In the setting of volume overload hypertrophy, myocytes elongate resulting in?
ventricular dilation
What is the best measure of hypertrophy in a dilated heart?
the heart weight
The hypertrophied heart is not accompanied by increase in blood supply despite the inc. in energy demand, making the heart vulnerable to?
ischemia-related decompensation