Mucus is a slippery secretion of the lining of the mucous membranes in the body. It is a viscous colloid containing antiseptic enzymes (such as lysozyme) and immunoglobulins. Mucus is produced by goblet cells in the mucous membranes that cover the surfaces of the membranes. It is made up of mucins and inorganic salts suspended in water. Phlegm is a type of mucus that is restricted to the respiratory tract, while the term mucus refers to secretions of the nasal passages as well.
In the respiratory system, mucus traps particles such as bacteria and dust, helping to prevent them from entering the body; this occurs especially in the nose. Mucus aids in the protection of the lungs by trapping foreign particles that enter the nose during normal breathing. Additionally, it prevents tissues from drying out.Increased mucus production in the respiratory tract is a symptom of many common illnesses, such as the common cold. The presence of mucus in the nose and throat is nor