Functions

• Respiration
• Air-conditioning of Inspired Air.
• Protection of lower Air way.
• Vocal resonance
• Nasal relfex functions
• Olfaction

Respiration

Nose is natural pathway for breathing. Mouth breathing is an acquired act. Newborn with choana atresia may asphyxiate to death.

• During Quiet Respiration: inspiratory Air current passes through middle part of nose.
• During expiration: Air current follows the same course as during inspiration, but entire air current is not expelled directly through Nares

Nasal Cycle

Nasal mucosa undergoes rhythmic cyclical congestion and decongestion. One working nasal chamber equal to both.

Air Conditioning of Inspired Air

• Filtration and purification

Nasal vibrissae act as filters for dust pollen, bacteria adhere to mucosa

• Temperature Control of Inspired Air

The region of middle and inferior turbinates is highly vascular with Cavernous venous space which control the blood flow and inc, dec the size of turbinate Efficient Radiator mechanism to warm.

• Humdification

Functions goes simultaneously with temperature control of Inspired air. Aor dry in winter and saturated with moisture in summer.

Protection of Lower Airway

• Mucociliary Mechanism

Nasal mucosa is rich in goblet cells, secretory gland (mucous and serous) and form mucous blanket. Floating on top of cilia which are constantly beating to carry it like a conveyer belt toward nasopharynx with speed of 5-10 mm/min.

• Enzyme & immunoglobins

Muramidase which kills bacteria and virus. IgA and Ig E and interferon also present.

• Sneezing

Protective reflex. Foreign particle sneezed out.

Vocal Resonance

Nose form a resonating Chamber for certain consonants in speech.

Nasal Reflex

Several reflexes are initiated by nasal mucosa. Smell of palatable food cause relfex secretion of saliva and gastric juice. Irritation Sneezing. Nasal function related to Nasobronchial and Nasopulmonary reflex.

Olfaction

Sense of smell is well developed in lower animals.

• Disorder of Smell

Anosmia: Total loss of sense of smell.

Hyposmia: Partial loss of sense.

Causes: Nasal obstruction, polyp, Allergic rhinitis.

Paraosmia: Perversion of Smell. Interprets the odours incorrectly.

Sense of smell can be checked by asking the patient to smell common odoura as lemon peppermint, rose, garlic, cloves.