Question

Major percentage of the heart __________ muscle, which is the only muscle with automaticity, meaning contractions are controlled by the autonomic nervous system.

1) Cardiac
2) Smooth
3) Rough
4) Hard

Answer 1

Cardiac muscle, found only in the heart, is the major percentage of the heart and is controlled by the autonomic nervous system. It is not under conscious or voluntary control.

Step-by-step explanation:

Cardiac muscle, found only in the heart, is the major percentage of the heart. It is the only muscle with automaticity, meaning that contractions are controlled by the autonomic nervous system. The involuntary contractions of cardiac muscle are controlled by electrical impulses from specialized cells in the heart known as the sinoatrial node.

Even though cardiac muscle has automaticity, it is not under conscious or voluntary control. If the cardiac muscle were under conscious or voluntary control, the heart rate and contractions would be influenced by our conscious decisions, leading to irregular heartbeats and potential health complications.