At first when some solid food or liquid goes into the mouth, it is chewed and manipulated there to make it ready for swallowing. But lack of control, strength or feeling, which may happen due to nerve disease or stroke, can push the food or liquid directly to the throat causing serious choking hazard.
At the oral stage the tongue drives the chewed food particles and liquid to the back of the mouth. The food particles create muscle rigidity and contractions. The muscle which opens at the back of the mouth to let the food move into the throat can malfunction and trigger aspiration (food morsels moving into the windpipe), resulting in chocking.
This stage is also known as pharyngeal stage. The mouth is connected to the pharynx through a swallowing tube or esophagus to allow food or liquid to pass from one organ to the other. But due to muscle contraction food may get stuck in the chest.
At the final stage or esophageal stage food or liquid passes through the esophagus and the lower esophageal sphincter muscle allows food into the stomach. But the lack of strength of the esophageal muscle at the opening of the stomach can create reflux, a condition where acidic secretions are forced to come back up into the stomach.