Multiple choice

Which among the following does not characterises a mammalian heart?

  1. The heart is effectively a syncytium.

  2. Few cardiac cells can contract without any signal from the nervous system.

  3. The SA node generates electrical impulses.

  4. The impulses are delayed for about 0.1s at bundle of His.

  5. This entire cycle, a single heart beat, lasts about 0.8 seconds.

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The atrioventricular node is located in the wall between the right atrium and the right ventricle. Here, the impulses are delayed for about 0.1s before spreading to the walls of the ventricle.

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