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WorksheetsCardio Quiz
Total questions: 15
Worksheet time: 30mins
All the following are correct except:
The left atrial wall is about the same thickness as the right atrium
The left ventricle is separated from the left atrium by bicuspid valve
Purkinje system allows the excitation of all ventricular muscle fibers to occur at nearly the same time
The right heart receives oxygenated blood from the four pulmonary veins
The atrio-ventricular valves:
Have three cusps for each valve
Their closure is initiated when the ventricular pressure exceeds atrial pressure
Open by contraction of papillary muscles
None of the above
The left ventricle has a thicker wall than the right ventricle because:
It is richer in blood supply
It ejects blood through a narrower orifice
It ejects a greater cardiac output
It ejects blood against a higher pressure
Which is not a part of the specialized self-excitable conductive system of the heart?
SA node
AV node
Papillary muscle
Bundle of His
Action potential of skeletal muscles differs from that of cardiac muscle in:
it is propagated more slowly
it is shorter in duration
it has a higher amplitude
it has no plateau
all of the above
Regarding the ionic basis of action potential in cardiomyocytes, which is incorrect?
Phase 0: Na influx
Phase 1: K influx
Phase 2: Ca influx
Phase 3: K efflux
Action potential of the cardiac muscle is characterized by the presence of plateau which:
in the ventricular muscle it reached 100 m sec
in the atrial muscle, it reached 300 m sec
it result from a balance between Ca++ influx and K+ efflux
it result from an inflow of Cl- and outflow of bicarbonate ions
In the sinoatrial (SA) node, phase 4 depolarization (pacemaker potential) is attributable to
an increase in K+ conductance
an increase in Na+ conductance
a decrease in Cl— conductance
a decrease in Ca2+ conductance
The cardiac muscle is characterized by having all the following except
intercalated disk connecting ms
A T system located at the Z line
The same refractory period characteristics as the skeletal ms
Acts as a physiological syncytium
Positive chronotropic effect of sympathetic stimulation is
Mediated through activation of B2-adrenergic receptors
Due to activation of L-type Ca++ channels
Blocked by cAMP
Due to rapid influx of Na+ increasing rapidity of funny current
The absolute refractory period of cardiac muscle:
Coincides with total duration of action potential
During which the heart can respond to a maximal stimulus
Is longer than the refractory period of the skeletal muscle
Is the period during which delayed rectifier K channels are inactivated
Negative inotropic mechanisms include all except:
Ischemia of cardiac muscle
Calcium channel blockers
Inhibition of cAMP production
Inhibition of Na-K pump
Ventricular pressure is higher than the atrial pressure in all phases of the cardiac cycle except in:
isometric contraction phase
atrial systole phase
maximum ejection phase
reduced ejection phase
Which phase of the cardiac cycle is absent if there is no P wave on the electrocardiogram?
Atrial systole
Isovolumetric ventricular contraction
Reduced ventricular ejection
Rapid ventricular filling
At the beginning of which phase of the cardiac cycle does the second heart sound occur?
Isovolumetric ventricular contraction
Reduced ventricular ejection
Isovolumetric ventricular relaxation
Rapid ventricular filling
