Mechanical Properties of the Heart

Were you able to watch the videos in Canvas?

• Yes

• Yes, but did not finish

• No

Arrange the steps in the excitation-contraction coupling of cardiac muscles:

• DHP receptors open to allow Ca2+ influx.

• Free Ca2+ binds to tropC exposing the myosin-binding site.

• Ca2+ influx triggers opening of ryanodine receptors.

• Action potentials traveling down the T-tubules depolarize the cell membrane.

• Actin myosin binding occurs.

Which of the following exhibits positive inotropy?

• beta 1 receptor activation

• beta 1 receptor inhibition

• muscarinic receptor activation

What will be the effect of Na+/K+-ATPase inhibitor on the contraction of cardiac muscles?

Arrange the events in cardiac cycle that occurs after atrial systole.

• Diastasis

• Ejection phase

• Isovolumetric contraction

• Isovolumetric relaxation

• Rapid ventricular filling

Match the heart sounds with their causes.

• Closure of SL valves

• S4

• Rush of blood during rapid ventricular filling

• S2

• Closure of AV valves

• S3

• Vibration produced by the atrial muscles when contracting against noncompliant ventricles

• S1

Can we give beta blockers on patients with heart failure?

• Yes

• No

Which best describes cardiac output?

• The volume of blood pumped out per ventricular contraction

• The volume of blood pumped out per minute

• The portion of the end-diastolic volume that is ejected.

• The number of beats per minute.

Which pressure-volume loop depicts the effects of changes in inotropy to stroke volume?

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