An organ system, (sometimes simply system), is a group of organs that work together to carry out a particular task. In humans and other animals, the organ systems are integumentary system, lymphatic system, muscular system, nervous system, reproductive system, urinary system, respiratory system, skeletal system, and immune system.
In humans, the digestive system is fundamentally comprised of the gastrointestinal tract. In particular, the gastrointestinal tract is comprised of the following organs: mouth, pharynx, esophagus, stomach, small intestine, large intestine, and rectum. It also includes accessory digestive glands such as salivary glands, liver, gallbladder, and pancreas. These organs and glands work together to digest foodstuff into smaller components that are absorbable forms to be assimilated by the body. Digestion begins in the mouth where salivation and chewing (mastication) aid in the formation of a bolus. The bolus is swallowed down the esophagus, into the stomach where it is mixed with the gastric juice. The resulting chyme moves into the small intestine (particularly the duodenum) where it will be fully broken down and absorbed (as chyle) into the lymphatic system. Reabsorption of water and other minerals takes place in the large intestine, particularly in the colon. The wastes are formed into faeces, which will be expelled from the rectum via the anus through defecation.
In other animals, there are specialized structures included in the digestive system. For instance, the crops in certain birds serve as a pouch in the gullet where food is stored or prepared for digestion. Ruminants have a stomach with four compartments, namely: rumen, reticulum, omasum, and abomasum (i.e. true stomach).
- Systema digestorium
- gastrointestinal system
- alimentary system
- alimentary apparatus
- digestive apparatus