481. Heart muscle, true are all except_______________?

A. Act as syncytium
B. Has multiple nuclei
C. Has gap junctions
D. Has branching

482. Isovolumetric relaxation ends immediately after________________?

A. AV Valve closes
B. When ventricular pressure falls below aortic pressure
C. When ventricular pressure falls below atrial pressure
D. None of the above

483. Ventricular muscle receives impulses directly from the_______________?

A. Purkinje system
B. Bundle of HIS
C. Right and left bundle branches
D. AV node

484. Distribution of blood flow is mainly regulated by the________________?

A. Arteries
B. Arterioles
C. Capillaries
D. Venules

485. Effect on force of contraction of heart is_____________?

A. Chronotropic effect
B. Dromotropic effect
C. Bathmotropic
D. Ionotropic effect

486. Cardiac output is maximum to _________________?

A. Liver
B. Brain
C. Kidney
D. Heart

487. Absolute period when whole heart is in diastole is______________?

A. 0.7 seconds
B. 0.3 seconds
C. 0.7 seconds
D. 0.4 seconds

488. Cardiac cycle duration in man is_______________?

A. 0.4 seconds
B. 0.8 seconds
C. 1.2 seconds
D. 1.6 seconds

489. Coronary blood flow is usually predominantly controlled by_____________?

A. Auto regulation
B. Hormones
C. Parasympathetic impulses
D. Sympathetic impulse

490. Fastest conducting tissue in human heart _________________?

A. AV node
B. SA node
C. Bundle of His
D. Purkinje fibers

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