What is the lower part of the rectum?

The lower part of the rectum is known as the anal canal, which is the final section of the gastrointestinal tract, measuring about 2 to 4 centimeters in length. It serves as the passageway for stool to exit the body and is surrounded by anal sphincters that help control bowel movements. The anal canal is lined with sensitive tissue and plays a key role in the defecation process.