Part 2 Flashcards
platelets help in the repair of a damaged vessel wall by releasing what substance
growth factor
normally what prevents platelets from adhering to a normal endothelium
glycoproteins in the platelet wall
what function does thromboxane A2 play in activation of platelets
potentates platelet granule release
what is not a function of prostacyclin
acts as a vasoconstrictor
how does aspirin block the formation of both thromboxane A2 and prostacyclin production
blocks FA cyclooxygenase
which is capable of dissolving or liquifying a blood clot
plasmin
how does dicumarol function as an anticoagulant
inhibits liver clotting factors
what is the cause of a repercussion injury in the myocardium
free radical damage
what effect will occur if fast Na channels in a cardiac cell is blocked
the cell will depolarize at a slower rate
if EDV is 150 mL and ESV is 100 mL, what is the ejection fraction
33%
during isovolumic contraction to the left-sided valves are in what state
mitral closed, aortic open
most of the blood ejected from the ventricles is ejected in the first half of the ejection phase
true
what percent of blood that moves from atria to ventricles is actively pumped by the atria
25%
what is the major function of the AV node
delay the wave of depolarization from entering the ventricles
the stable resting polarized state in a typical cardiac muscle cell is due to
K at its Nernst equilibrium and an impermeable membrane to Na and Ca
under resting conditions, what % of oxygen is being extracted fro the arterial blood that is perfusing the myocardium
about 70%
how does digitalis act to increase strength of contraction
decreases function of calcium exchange protein
the first heart sound is associated with what event
closure of the AV valves
a machinery murmur heard throughout the entire cardiac cycle is likely associated with what condition
patent ductus arteriosis
a machinery murmur heard throughout the entire cardiac cycle is likely associated with what condition
patent ductus arteriosis
a diastolic murmur would likely be associated with what condition
aortic insufficiency
as systemic arterial blood pressure is increased, what happens to the strength of left ventricular contraction if the ANS effect on the heart is blocked
decrease in LV contractile strength
what is the function of the papillary muscles in the wall of the RVs when they contract
prevents prolapse of the tricuspid valve
which are dependent on ANS function
pressure induced homeometric autoregulation
how does the stretch on the SA nose increase HR
by increasing membrane permeability to Na/Ca
increase EC K levels 2-3X above normal will have what effect on myocardial performance
extreme weakness and flaccidity
what effect would a fever of 100 degrees F have on resting HR
increased HR 10 bpm
most of the energy consumed by the heart is associated with
the production of heat
the principal energy source for cardiac output is
FAs
increased stretch on the ventricular myocardium at the end of diastole is associated with
increase calcium influx
PSNS activation can cause inhibition of NE release presynaptically
true
what is most responsible for the all or none response of the cardiac myocardium
intercalated discs
what is not a feature of the SA node
stable resting polarized state
in a third degree AV block, what is true
the atria and ventricles are beating independently
describe atrial repolarization
buried in the QRS complex
what normally prevents cells other than SA nodal cells from firing spontaneously
purkinje cells
if the net deflection of the QRS complex in lead I is negative 5 mm, and the net deflection in lead AvF is positive 5 mm, what can you say about the mean electrical axis
right axis deviation
