Anus in the context of "Flatus"

Feces (also faeces or fæces) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relatively small amount of metabolic waste products such as bacterially-altered bilirubin and dead epithelial cells from the lining of the gut.

Feces are discharged through the anus or cloaca during defecation.

Bilateria (/ˌbaɪləˈtɪəriə/) is a large clade of animals characterised by bilateral symmetry during embryonic development. This means their body plans are laid around a longitudinal axis with a front (or "head") and a rear (or "tail") end, as well as a left–right–symmetrical belly (ventral) and back (dorsal) surface. Nearly all bilaterians maintain a bilaterally symmetrical body as adults; the most notable exception is the echinoderms, which have pentaradial symmetry as adults, but bilateral symmetry as embryos. With few exceptions, bilaterian embryos are triploblastic, having three germ layers: endoderm, mesoderm and ectoderm, and have complete digestive tracts with a separate mouth and anus. Some bilaterians lack body cavities, while others have a primary body cavity derived from the blastocoel, or a secondary cavity, the coelom. Cephalization is a characteristic feature among most bilaterians, where the sense organs and central nerve ganglia become concentrated at the front end of the animal.

Bilaterians constitute one of the five main lineages of animals, the other four being Porifera (sponges), Cnidaria (jellyfish, hydrozoans, sea anemones and corals), Ctenophora (comb jellies) and Placozoa. They rapidly diversified in the late Ediacaran and the Cambrian, and are now by far the most successful animal lineage, with over 98% of known animal species. Bilaterians are traditionally classified as either deuterostomes or protostomes, based on whether the blastopore becomes the anus or mouth. The phylum Xenacoelomorpha, once thought to be flatworms, was erected in 2011, and has provided an extra challenge to bilaterian taxonomy, as they likely do not belong to either group.

The gastrointestinal tract (also called the GI tract, digestive tract, and the alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is one of the largest of the body's systems. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines.

Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores (ostia) throughout their body for digestion and a larger dorsal pore (osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion.

Pubic hair (or pubes /ˈpjuːbiːz/, /pjuːbz/) is terminal body hair that is found in the genital area and pubic region of adolescent and adult humans. The hair is located on and around the sex organs, and sometimes at the top of the inside of the thighs, even extending down the perineum, and to the anal region. Pubic hair is also found on the scrotum and base of the penile shaft (in males) and on the vulva (in females). Around the pubis bone and the mons pubis that covers it, it is known as a pubic patch, which can be styled.

Although fine vellus hair is present in the area during childhood, pubic hair is considered to be the heavier, longer, coarser hair that develops during puberty as an effect of rising levels of hormones: androgens in males and estrogens in females.

Defecation (or defaecation) follows digestion and is the necessary biological process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces (or faeces) from the digestive tract via the anus or cloaca. The act has a variety of names, ranging from the technical (e.g. bowel movement), to the common (like pooping or crapping), to the obscene (shitting), to the euphemistic ("doing number two", "dropping a deuce" or "taking a dump"), to the juvenile ("going poo-poo" or "making doo-doo"). The topic, usually avoided in polite company, forms the basis of scatological humor.

Humans expel feces with a frequency varying from a few times daily to a few times weekly. Waves of muscular contraction (known as peristalsis) in the walls of the colon move fecal matter through the digestive tract towards the rectum. Flatus may also be expulsed. Undigested food may also be expelled within the feces, in a process called egestion. When birds defecate, they also expel urine and urates in the same mass, whereas other animals may also simultaneously urinate during defecation, but the processes are spatially separated. Defecation may also accompany childbirth and death. Babies defecate a unique substance called meconium prior to eating external foods.

Deuterostomes (from Greek: lit. 'second mouth') are bilaterian animals of the superphylum Deuterostomia (/ˌdjuːtərəˈstoʊmi.ə/), typically characterized by their anus forming before the mouth during embryonic development. Deuterostomia comprises three phyla: Chordata, Echinodermata, Hemichordata, and the extinct clade Cambroernida.

In deuterostomes, the developing embryo's first opening (the blastopore) becomes the anus and cloaca, while the mouth is formed at a different site later on. This was initially the group's distinguishing characteristic, but deuterostomy has since been discovered among protostomes as well. The deuterostomes are also known as enterocoelomates, because their coelom develops through pouching of the gut, enterocoely.