How does the body prevent food from entering the windpipe?

The body prevents food from entering the windpipe through a flap of tissue called the epiglottis.

The human body has a sophisticated mechanism to ensure that food and drink are directed into the oesophagus, not the windpipe. This is primarily achieved through the action of the epiglottis, a leaf-shaped flap of cartilage located at the base of the tongue, where the throat divides into the oesophagus and the windpipe (trachea).

When we swallow, a complex reflex is triggered. The larynx (voice box) moves upward, which helps the epiglottis to close over the windpipe, creating a seal that prevents food and drink from entering. This is known as the swallowing reflex. It's an involuntary action, meaning it happens automatically without us having to think about it.

The process of swallowing is divided into three stages: the oral phase (where food is prepared for swallowing), the pharyngeal phase (where the food is propelled into the oesophagus), and the oesophageal phase (where the food is transported to the stomach). The epiglottis plays a crucial role in the pharyngeal phase.

If the epiglottis doesn't function properly, or if someone tries to swallow and breathe at the same time, food or liquid can get into the windpipe. This can cause choking or aspiration pneumonia, a serious lung infection.

In summary, the body uses the epiglottis as a sort of gatekeeper to prevent food and drink from entering the windpipe. This is part of a complex reflex that ensures we can eat and drink safely.