A sneeze is a reflex action controlled by the brain's respiratory center, specifically triggered by irritation of the nasal passages.
The Sneeze Reflex: A Neurological Process
The sneeze reflex is initiated by sensory neurons in the nasal passages. When these neurons detect irritants (like dust, pollen, or an infection), they send signals via a peptidergic pathway to the brainstem. This pathway, as detailed in research published in Cell (June 15, 2021), uses peptides as neurotransmitters. The brainstem, in turn, coordinates the complex muscular contractions necessary for the forceful expulsion of air from the lungs through the nose and mouth. A study published in PMC highlights that the sneeze-evoking region is located within the ventromedial SpV of the brainstem (https://pmc.ncbi.nlm.nih.gov/articles/PMC8396370/). This process is involuntary, meaning we generally don't consciously control the initiation of a sneeze.
Factors Triggering Sneezes:
- Irritants: Dust, pollen, pepper, strong smells.
- Infections: Common cold, flu, allergies.
- Medications: Some nasal sprays.
- Bright light: A surprising trigger for some individuals (photic sneeze reflex).
Can We Control Sneezes?
While we can't completely stop a sneeze once it's initiated, some degree of control is possible. Pinching the bridge of the nose or rubbing it can sometimes lessen the intensity or prevent the sneeze entirely, as suggested by ABC News (https://www.abc.net.au/news/2019-09-11/can-you-control-how-loud-you-sneeze/11472994). This might involve interfering with the nerve signals reaching the brainstem. However, the primary control over sneezing resides within the involuntary reflexes of the nervous system.
Importance of Sneeze Hygiene
Sneezing is a powerful method of spreading respiratory droplets, carrying viruses and bacteria. The CDC emphasizes the importance of covering sneezes and practicing good hand hygiene to prevent the transmission of illnesses (https://www.cdc.gov/hygiene/about/coughing-and-sneezing.html and https://www.cdc.gov/respiratory-viruses/prevention/hygiene.html).
