Question

Name the 2 sphincters located at the anus. Which sphincter undergoes involuntary relaxation during the defecation reflex?

Answer 1

Internal sphincter muscle of the anus and external sphincter muscle of the anus.

During defecation, the reflection of relaxation occurs in the inner sphincter muscle of the anus (involuntary), which is caused by the pressure of the fecal stools in the rectum.