Question

An example of unstriated muscles which are entirely involuntary is located ________.

• A. In the diaphragm
• B. In the eyelid
• C. At the pylorus
• D. At the base of external ear

Answer 1

The correct option is C At the pylorus

The muscles of the alimentary canal that includes the esophagus, stomach, small and large intestine are completely involuntary, that is, not controlled by will. The junction between two regions of the alimentary canal, the stomach and the small intestine is guarded by a circular muscle or sphincter the pylorus which allows small portions of partially digested food into the small intestine. The muscles of the sphincter are uninucleate, spindle shaped and entirely involuntary.

So, the correct answer is 'At the pylorus'