i. The wind pipe is technically called the trachea.

ii. Its opening is covered with a covering called the epiglottis. The opening of the food pipe (esophagus).

iii. The pharynx is a junction where both the oesophagus (food pipe) and the trachea (windpipe) open.

iv. In the absence of food, the oesophageal sphincter muscle is contracted and the epiglottis is up, allowing air to flow through the trachea to the lungs.

v. When food swallowing, the oesophageal sphincter muscle relaxes and the epiglottis comes and closes glottis which prevents food from entering the trachea.

vi. But food sometimes enters the wind pipe and causes choking.