01 / Location & anatomical relationships
At the end of the large intestine, inside the pelvis.
02 / Structure & organization
The rectum follows the sigmoid colon and lies within the pelvis before the anal canal. Its wall can accommodate temporary filling. Distension activates sensory pathways involved in the defecation reflex.
03 / Function
It holds stool before it leaves your body.
04 / Mechanism
Its wall stretches when stool arrives. Nerves signal that it is filling, and muscles coordinate with the anal sphincters when stool is passed. It is mainly a temporary holding area rather than a place of digestion.
Working together: digestive system
Teeth break food into pieces, the stomach mixes it, and the small intestine absorbs nutrients. Your blood then carries these nutrients around your body.
Meet this body system →FOR DEEPER STUDY
Connect structure with function
Continence depends on rectal storage, anal sphincters, pelvic-floor muscles and neural control. The rectum and anus are adjacent structures with different roles.
Check your understanding
Locate the rectum in relation to its neighbors. Explain how the structural features described above support its function, then distinguish it from a nearby structure with a different role.
Keep learning
Further reading: NIDDK: Your Digestive System & How It Works.
Continue with OpenStax Anatomy and Physiology for system-level study. This atlas is educational and has not undergone independent medical peer review.