Question

Select the INCORRECT statement.

• A. Cardiac activity is regulated by autonomic nerves supply to SA node.
• B. Conducting gel is applied between electrodes and skin to detect tiny impulses in the record of electrocardiogram.
• C. QRS complex represents spreading of impulse from SA node to bundle of His, AV node and Purkinje fibres.
• D. Degeneration of heart muscles may result from factors such as malnutrition, chronic infection etc.

Hint:

The QRS complex in an ECG represents ventricular depolarization, not the spreading of the impulse from the SA node.

Answer 1

The Correct Option is C

Step 1: Understanding the ECG.
The QRS complex represents the depolarization of the ventricles, not the spreading of the impulse from the SA node. The SA node initiates the impulse, which spreads through the atria and then to the AV node, bundle of His, and Purkinje fibers.
Step 2: Analyzing the options.
(A) Cardiac activity is regulated by autonomic nerves supply to SA node: Correct — The SA node is regulated by autonomic nerves, controlling heart rate.
(B) Conducting gel is applied between electrodes and skin to detect tiny impulses in the record of electrocardiogram: Correct — Conducting gel helps improve electrical signal detection for ECG.
(C) QRS complex represents spreading of impulse from SA node to bundle of His, AV node and Purkinje fibres: Incorrect — The QRS complex represents ventricular depolarization, not the spreading of the impulse from the SA node.
(D) Degeneration of heart muscles may result from factors such as malnutrition, chronic infection etc.: Correct — Heart muscle degeneration can result from malnutrition and chronic infections.
Step 3: Conclusion.
The incorrect statement is (C) QRS complex represents spreading of impulse from SA node to bundle of His, AV node and Purkinje fibres.