
22. The Rectum and Anus
An 8-inch chamber that connects the colon to the anus. The rectum receives stool from the colon, sends signals to the brain if there is stool to be evacuated, and holds stool until evacuation can happen. The last part of the digestive tract is the anus, which consists of pelvic floor muscles and two anal sphincters (internal and external). Together their jobs are to detect rectal contents.

Whether they are liquid, gas, or solid, and then control when stool should and shouldn’t be excreted from your body. The external sphincter of the anus is under voluntary control. This means you can decide whether you will open your bowels or not. Young children have to learn to control this during toilet training.