Myocardial E-C Coupling MCQ Quiz | Cardiovascular System

Welcome to this specialized quiz on Myocardial Excitation-Contraction (E-C) Coupling, a cornerstone of cardiovascular physiology for MBBS students. This quiz is designed to test your understanding of the intricate sequence of events that translates an electrical action potential into a coordinated mechanical contraction of the heart muscle. You will be challenged on topics including ion channels, calcium-induced calcium release (CICR), sarcoplasmic reticulum function, and the roles of key regulatory proteins. A strong grasp of these concepts is vital for understanding cardiac function in both health and disease. This quiz consists of 25 multiple-choice questions. After submitting, you can review your score and download all questions with their correct answers in a PDF format for future revision.

1. The primary trigger for calcium release from the sarcoplasmic reticulum in cardiac myocytes is:

2. During which phase of the cardiac action potential does the major influx of Ca2+ occur?

3. The ryanodine receptor (RyR2) in cardiac muscle is located on the membrane of the:

4. Which protein is responsible for sequestering Ca2+ within the sarcoplasmic reticulum?

5. The primary mechanism for removing Ca2+ from the cytosol to induce myocardial relaxation is:

6. In its unphosphorylated state, phospholamban has what effect on SERCA2a?

7. Beta-adrenergic stimulation enhances myocardial contractility (inotropy) primarily by:

8. A key difference in E-C coupling between cardiac and skeletal muscle is that cardiac muscle:

9. The therapeutic effect of Digoxin is primarily mediated by:

10. The term ‘lusitropy’ refers to:

11. Which subunit of the troponin complex directly binds to Ca2+ to initiate contraction?

12. The Frank-Starling mechanism is primarily explained at the cellular level by:

13. The stoichiometry of the Na+/Ca2+ exchanger (NCX) in its forward mode is:

14. What is a “calcium spark”?

15. Acidosis negatively impacts cardiac contractility primarily by:

16. The close apposition of a T-tubule with a terminal cisterna of the SR in a cardiac myocyte is called a:

17. Which of the following plays the LEAST significant role in Ca2+ extrusion from the cardiac myocyte cytosol under normal conditions?

18. The force of cardiac contraction is most directly proportional to:

19. In chronic heart failure, the expression and activity of which protein is typically downregulated?

20. The function of T-tubules in cardiac myocytes is to:

21. The binding of Ca2+ to troponin C leads to a conformational change that primarily moves which protein?

22. An increase in heart rate can lead to an increased force of contraction (treppe or staircase phenomenon). This is best explained by:

23. L-type Ca2+ channels are also known as:

24. What is the effect of catecholamines on phospholamban?

25. Termination of the cross-bridge cycle and detachment of myosin from actin requires:

Author

  • G S Sachin Author Pharmacy Freak
    : Author

    G S Sachin is a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. He holds a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research and creates clear, accurate educational content on pharmacology, drug mechanisms of action, pharmacist learning, and GPAT exam preparation.

    Mail- Sachin@pharmacyfreak.com

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