Digestive System
A 9-metre tube — plus the liver and pancreas — that turns food into fuel.
Digestion begins the moment food enters the mouth and continues for hours as enzymes, acid, bile and trillions of gut microbes break food into absorbable nutrients. The gut is now understood to be a major immune and even neurological organ in its own right, communicating constantly with the brain via the vagus nerve.
Key organs & structures
How it connects
The majority of the body's immune tissue sits directly in the gut wall.
Gut inflammation is linked to several inflammatory skin conditions.
The gut produces a large share of the body's serotonin, influencing mood.
Common goals
Common symptoms
Deep-dive guides in the digestive system
Conditions involving this system
Symptoms involving this system
Did you know?
- • Your gut is lined with its own independent nervous system, sometimes called the 'second brain'.
- • The liver can regenerate a substantial share of its own tissue after injury or partial removal.