What is the anus understanding?

The anus is part of the digestive tract. This is the opening at the end of the outlet that starts from the mouth, and its function is to remove waste from the digestive system. This term comes from the Latin word meaning "circle" or "ring," and refers to the sphincter muscle that controls the opening and closing of the anus.

In mammals, solid or semi-solid waste is excreted through this opening, while liquid waste is excreted through the urethra. This physiological characteristic is one that distinguishes mammals from other animals. Birds, reptiles and amphibians only have a single hole, called a "cloaca" or "vent," used to excrete both liquid and solid waste, and for reproduction and laying eggs.

The part of the digestive tract just before the anus in humans and mammals is the rectum. When food has passed through the digestive tract, nutrients and water are both removed, leaving a collection of undigested waste called faeces. Feces can consist of digestible tissue from plants or animals, as well as dead bacteria from the intestines. As dirt accumulates in the rectum, an increase in pressure causes a series of muscle contractions. This contraction removes impurities along the rectum and relaxes in the anus, which opens, expels from the body. This process is called defecation.

Many human cultures have important taboos relating to defecation, and some forms of cleansing are almost always practiced. This might include washing the anal area with soft soap and water, or wiping with a cloth or paper. Regular cleaning is good for maintaining the health of the digestive tract, although cleaning with coarse material can cause painful irritation.

The anus has a large number of nerve endings, which makes it very sensitive. As a result, the anal area is stimulated in some form of generative activity. Anal sex is considered taboo or controversial in some cultures. Like all generative activities, unprotected anal sex can lead to generative infectious infections.