• Appendix

• cecum

• Colon

• Rectum

• Anus

Defecation reflex

1. Rectum fills
2. Rectal distention (stretch receptors) trigger spinal cord reflex
   1. afferent signals to spinal cord via pelvic nerve
   2. efferent signals to descending colon, sigmoid colon and rectum through pelvic nerve →   SMC rectal wall contracts (propelling to anus) and internal anal sphincter relaxes
3. External anal sphincter under conscious control (striated muscle) pudendal nerve control. sacral segments influenced by hypothalamus midbrain and cerebral cortex

other effects include deep breath, closure of glottis and increased abdo pressure to expel contents