What is Digestive system?
{{one source}} [[File:Digestive system diagram en.svg|thumb|270px|Human digestive system]] The '''digestive system''' is the parts of the [[body]] that [[Digestion|digest]] food. It is the '''gastrointestinal system'''. It breaks down food into simple [[chemical]]s which can be [[wikt:absorb|absorbed]] into the [[blood stream]]. It also produces waste, which be expelled by passing gas, pooping, or even passing urine. From the blood stream, nutrients go to the [[liver]], which is a kind of chemical factory for the body. The liver adjusts the nutrients so that the mix is what the body needs. In the stomach, gastric acid is introduced. This is basically dilute [[hydrochloric acid]]. It is very reactive and has a [[pH|pH level]] of 1.5 to 3.5.<ref>Elaine N. Marieb, Katja Hoehn, Katja N. Hoehn 2018. ''Human anatomy and physiology'', 11th edition. Pearson Education, p1264. ISBN 978-0134580999</ref> The stomach has a layer of [[mucus]] to protect itself from the acid. The digestive system also get rid of waste material. The gastrointestinal system starts at the [[lip]]s and ends at the [[anus]]. Animals like [[worm]]s, [[insect]]s, [[mammal]]s, [[bird]]s, [[fish]], and [[human|people]] all have digestive systems. Passing gas during digesting is normal. It is Mother Nature's way of releasing excess gas. The digestive system is not just the '''gut''', but also many other [[Organ (anatomy)|organs]] which help us digest food. For example, digestive [[enzymes]] are needed to break down [[carbohydrates]] and [[meat]] into substances which can be absorbed. The absorbed food then goes to the rest of your body, and makes you healthy. The parts of the [[human]] digestive system are the same in many animals: *[[Mouth]] *[[Pharynx]] *[[Oesophagus]] *[[Stomach]] *[[Intestine]]s **[[Small intestine]] ***[[Duodenum]] ***[[Jejunum]] ***[[Ileum]] **[[Large intestine]] ***[[Cecum]] ***[[Colon (anatomy)|Colon]] *[[Rectum]] *[[Anus]] Other organs that are part of the gastrointestinal system but are ''not'' part of the gut are: