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Question #46864
The Question
A novel pharmacological agent selectively binds to and irreversibly blocks the gap junctions located within the intercalated discs of a mammalian heart. Which of the following physiological consequences is most likely to occur?
Options
- A.
The SA node will lose its auto-excitability, resulting in the immediate cessation of action potential generation.
- B.
The cardiac tissue will lose its functional syncytium property, leading to asynchronous contractions and conduction blocks.
- C.
The rate of ventricular depolarization will increase as impulses bypass the AV node through desmosomes.
- D.
The cardiac muscle fibers will undergo sustained tetanic contractions due to the trapping of intracellular calcium.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Intercalated Disc Function|Conducting System Sequence|ECG Wave Interpretation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Differentiating between the generation of an impulse (SA node auto-excitability) and its propagation (gap junctions).
Common Misconception: Students often confuse the distinct roles of the two components of intercalated discs: desmosomes (mechanical anchoring) and gap junctions (electrical syncytium), or assume SA node firing depends on surrounding tissue coupling.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Intercalated Disc Function |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |