The anus is the opening at the end of the digestive tract through which waste material is eliminated from the body. It is a part of the gastrointestinal system and is located at the end of the rectum.
The anus is made up of two sets of muscles: the internal anal sphincter and the external anal sphincter. The internal anal sphincter is made of smooth muscle and is under involuntary control, while the external anal sphincter is made of skeletal muscle and is under voluntary control.
The main function of the anus is to control the expulsion of feces from the body. The internal and external anal sphincters work together to regulate the passage of stool and prevent leakage between bowel movements.