Science behind sneezing

    Sneezing is a reflex that involves involuntary muscle contractions.

    

    The process begins when irritants like dust, pollen, or other foreign particles stimulate sensory receptors located in the nasal mucosa. These receptors rapidly send signals via the trigeminal nerve (三叉神經) to a designated area in the brainstem, sometimes referred to as the "sneeze center." In response, your body initiates a cascade of involuntary nerve signals that result in the rapid contraction of several muscle groups. Notably, the diaphragm, intercostal muscles, and muscles in the throat contract suddenly, forcing a powerful burst of air out of the lungs. This coordinated response effectively helps to expel the irritants from your respiratory system, protecting your airways and lungs.

(cascade: something arranged or occurring in a series or in a succession of stages so that each stage derives from or acts upon the product of the preceding)

    Because this reflex operates through neural pathways and muscle responses that you cannot consciously control, it is classified as an involuntary reflex. Although you might try to stifle (阻止) a sneeze, the underlying physiological mechanism is automatic, showcasing the body's remarkable ability to protect itself from potentially harmful invaders.

    Sneezing may come along with mucus. I experience further times of sneezing when I do not get rid of the nasal discharge using tissue.

    Sneezing often continues if nasal mucus is not cleared with a tissue, it is because mucus itself can continue to stimulate the sensitive receptors in your nasal passages. This mucus is not just a byproduct --- it is a complex mixture designed to trap dust, allergens, and other irritants. If the mucus stays in place, these irritants linger (逗留), repeatedly activating your sneeze reflex through the nerve endings in the nasal mucosa.

    The sneeze reflex is your body's rapid-response mechanism to expel unwanted particles from your respiratory system. When you blow your nose, you mechanically remove much of the mucus along with the trapped irritants. Without this cleaning action, those irritant signals can persist, effectively prolonging or even restarting the cycle of sneezes. In this way, blowing your nose serves as an important first step in breaking the chain reaction of sneezing.

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