How The Gut Functions
With the normal functioning of the gastrointestinal tract, the various components of the gut serve different purposes.
The sight and smell of food stimulates the senses and the gastrointestinal tract to be ready to receive and digest food. Food is ingested via the mouth where it is chewed as a way of beginning to break it down.
The gut is like a long assembly line and each part of the assembly line serves a different purpose. It is also important that the assembly line works in a smooth and co-ordinated way for it to be efficient. At each stage of the assembly line within the gut, signals are sent ahead to alert the following parts of the gut to be ready to do their part, as food is on it’s way.
On the inside of the gastrointestinal tract, there are muscles and nerve endings, in fact there’s an entire Enteric Nervous System, amongst many other things. Natural relaxation and contractions of the muscles (peristalsis), propels the food along and the nerve endings send signals back to the brain, as well as on to other parts of the gut.
Food travels along the oesophagus and through the oesophageal sphincter into the stomach, where acid is secreted and the stomach churns and further breaks down the food. The food commences it’s journey into the small intestine through the pyloric sphincter, first entering the duodenum, where more digestive enzymes are released. It then progresses on to the jejunum and ileum, also within the small intestine.
Here further digestion takes place and the nutrients are absorbed from the food in to the bloodstream to fuel the body and support immune function. It continues it’s journey propelled by peristalsis. Finally, what remains of the food, travels from the small intestine to where it meets the large intestine at the cecum, joining via the iloececal valve.
In the large intestine, the remnants can remain for many hours, as water is absorbed back in to the body and the fermentation of unabsorbed materials occurs. The waste is then stored in the rectum to be delivered from the body. Within the rectum are also the internal and external sphincters, which control the defecation process by involuntary and voluntary control mechanisms. As the faeces is stored within the rectum, the walls gradually expand and stretch, triggering the internal sphincter to commence defecation. The external sphincter has more voluntary control over whether to continue or halt this process. Finally, the waste is removed via the anus completing the digestive process.
The gut is designed to be independent and function to a large extent autonomously.