Which type of substance present in …

The human nose is the most protruding part of the face that bears the nostrils, and is the first organ of the respiratory system. The nose is also the principal organ in the olfactory system. The shape of the nose is determined by the nasal bones and the nasal cartilages, including the nasal septum which separates the nostrils and divides the nasal cavity into two. On average the nose of a male is larger than that of a female. The main function of the nose is respiration, and the nasal mucosa lining the nasal cavity and the paranasal sinuses carries out the necessary conditioning of inhaled air by warming and moistening it. Nasal conchae, shell-like bones in the walls of the cavities play a major part in this process. Filtering of the air by nasal hair in the nostrils prevents large particles from entering the lungs. Sneezing is a reflex to expel unwanted particles from the nose that irritate the mucosal lining. Sneezing can transmit infections, because aerosols are created in which the droplets can harbour pathogens. Another major function of the nose is olfaction, the informing of odours that the sense of smell carries out. The area of olfactory epithelium, in the upper nasal cavity contains specialised olfactory cells responsible for this function. The nose is also involved in the function of speech. Nasal vowels and nasal consonants are produced in the process of nasalisation. The nasal cavity is the third most effective vocal resonator. There are many plastic surgery procedures on the nose, known as rhinoplasties available to correct various structural defects or to change the shape of the nose. Defects may be congenital, result from nasal disorders or from trauma and these are carried out by reconstructive surgery. Procedures used to change a nose shape electively are carried out by cosmetic surgeries.

Mucous