<P> In the human respiratory system , mucus , also known as airway surface liquid ( ASL ) , aids in the protection of the lungs by trapping foreign particles that enter them , in particular , through the nose , during normal breathing . Further distinction exists between the superficial and cell - lining layers of ASL , which are known as mucus layer ( ML ) and pericilliary liquid layer ( PCL ) , respectively . `` Phlegm '' is a specialized term for mucus that is restricted to the respiratory tract , whereas the term `` nasal mucus '' describes secretions of the nasal passages . </P>
<P> In the human respiratory system , mucus , also known as airway surface liquid ( ASL ) , aids in the protection of the lungs by trapping foreign particles that enter them , in particular , through the nose , during normal breathing . Further distinction exists between the superficial and cell - lining layers of ASL , which are known as mucus layer ( ML ) and pericilliary liquid layer ( PCL ) , respectively . `` Phlegm '' is a specialized term for mucus that is restricted to the respiratory tract , whereas the term `` nasal mucus '' describes secretions of the nasal passages . </P>
what does mucus do in the respiratory system
what does mucus do in the respiratory system
aids in the protection of the lungs by trapping foreign particles that enter them , in particular , through the nose , during normal breathing
aids in the protection of the lungs by trapping foreign particles that enter them , in particular , through the nose , during normal breathing