Mouth

The mouth is the only part of the gastrointestinal tract where people have complete agency. Jaw movement begins after the mouth reaches its end-range open position. People control what enters the body through the mouth. People control how long food remains in the mouth. Control at the mouth directly influences digestive health outcomes. Oral function is linked to the gut's ability to maintain healthy movement. The mouth is connected to movement of food through the gastrointestinal tract. The full sequence includes placing the tongue up, opening the mouth fully, and moving the jaw forward and backward. The mouth is opened fully while the tongue remains pressed upward and outward. The mouth is described as important for digestive health.