Why do we make a sound and involuntarily close our eyes when we sneeze?

Sneezing is a complex defensive mechanism triggered by the body to rapidly expel irritants and pathogens from the respiratory tract. The sound of a sneeze arises through two stages: it begins with a sudden inhalation, followed by a forceful exhalation that occurs after muscle contraction and temporary closure of the mouth, which raises pressure inside the lungs and causes air to burst out suddenly, producing the familiar sound. Although the physiological mechanics and tongue position are identical across all humans, the tone varies depending on the shape of the mouth at the moment air is expelled. This process is controlled by a neural cycle that starts with stimulation of receptors in the nasal mucous membranes, which send signals via the trigeminal nerve to the brainstem to coordinate the contraction of the diaphragm and other muscles. Triggers are not limited to nasal irritation; about a quarter of the population sneezes when suddenly exposed to bright light due to a hereditary neural crossover. The automatic closing of the eyes during a sneeze is merely an involuntary reflex resulting from neural synchronization in the brain, serving to protect the eyes from flying droplets and germs. Conversely, doctors strongly warn against stifling a sneeze, as trapped pressure may seek an alternative exit, potentially causing health complications such as a ruptured eardrum or damage to small blood vessels. Source: “Cell” scientific journal