The<unk>  occurs when stimulation of<unk>  receptors in the respiratory tract by dust or other foreign particles produces a<unk> , which causes rapidly moving air which usually remove the foreign material before it reaches the lungs. This typically clears particles from the bronchi and trachea, the tubes that feed air to lung tissue from the nose and mouth. The larynx (voice box) and carina (at the bottom of the trachea, as it splits into bronchi) are especially sensitive.<unk>  receptors in the surface cells (epithelium) of the respiratory tract are also sensitive to chemicals. Terminal bronchioles and even the alveoli are sensitive to chemicals such as sulfur dioxide gas or chlorine gas.
Cough reflex
Pharyngeal reflex
Conscious breathing
Sense of balance
Snout reflex
Mouth breathing
Voice change
Pain tolerance