The stimulus for the defecation reflex is:
A)the stretching of the rectum
B)the contraction of the rectum
C)impulses from the spinal cord
D)contraction of the external anal sphincter

Question

Quizplus · Accepted Answer

The stretching of the rectum is the main stimulus for the defecation reflex. When fecal material fills the rectum, it stretches the walls of the rectum, which triggers sensory receptors to send signals to the spinal cord. This results in the reflexive relaxation of the internal anal sphincter and activation of the urge to defecate.

The Stimulus for the Defecation Reflex Is