Grades 3–5 · Organisms
How does a tickle in your nose become a sneeze?
A sneeze can begin when the inside of the nose is irritated. Sensory nerves in the nose respond and send signals toward the brain. Things such as smoke or other irritating material can set off this response. The nose provides the starting signal, but muscles elsewhere produce the movement of air.
In the diagramA sneeze coordinates a fast outward breathIrritated nosesensory nervessend signalsBrainstemnetworkscoordinateBreathingmusclesmove airA breath in comes first.Then air moves quickly out.Moving air can carry mucus and particles.Route is simplified; airflow speed is not predicted.
The signals reach coordinating networks in the brainstem, a region that connects the brain with the spinal cord. Messages then activate breathing muscles in a coordinated sequence. There is an inward breath before the forceful outward part of the sneeze. Several actions have to fit together to make that quick burst.
The outward airflow can carry mucus and particles away from the upper airway. This is why sneezing is described as a protective reflex: sensory input can lead to a rapid, organized response without a planned decision to sneeze. The response links what the nose senses with coordinated actions of the breathing muscles.
About this explanation
Starting knowledge: Know that nerves carry messages and muscles move parts of the body.
Sources
- Li and colleagues; Washington University School of Medicine; National Library of Medicine — Sneezing reflex is mediated by a peptidergic pathway from nose to brainstem
- NHS — Non-allergic rhinitis