What are the functions of the turbinates?
•Design of the nasal cavity acts to reduce speed of air flow
•Disturb laminar airflow, making it turbulent
•Throwing the cavity into folds increases surface area/volume ratio
–Air spends a long time in the nasal cavity
–Dry air is humidified
–Incoming cold air is warmed to within 1oC of body temperature
–Incoming warm air is cooled to within 1oC body temperature
–Dust particles in air are filtered
–Airborne bacteria is filtered out
What Main Factor Underpins Functions of Turbinates?
Increase in cross-sectional area of the nasal cavity will reduce velocity of air-flow through it
•Narrow anterior naris
•Narrow choanae (Increase flow-again)
What is the structure of the nasal mucosa?
•Respiratory Epithelium lining the upper
airways is classified as ciliated
pseudostratified columnar epithelium (with goblet cells)
•All cells of the epithelium form a single cell
layer, with each cell making contact with the
•Tight packing of the cells leads to squeezing
of the Nuclei to various levels along the
longitudinal axis of the cell, giving the
appearance of multi-layering
•3 Cell types- Goblet, ciliated (mucocilliary escalator) and basal cells
Explain why nasal mucosa might be found to be red and swollen?
Redness- due to highly vascularity, supplied from branches of both the internal & external carotid arteries
Moist – lined by respiratory epithelium
Serous & mucus secretions
Swollen - due to inflammation of the mucous membrane.
Explain why a patient with red and inflamed nasal mucosa might have copious nasal discharges?
Nasal discharges would have been due to extravasation of fluid from the inflamed mucosa and associated increased mucous secretions, etc.
Explain the underlying causes of headaches & facial pain.
•Blocked nasal passages; discharge of secretions from the sinuses interrupted; stuffy feeling; irritation of the mucosa;
•Nerves supplying the nasal cavity & sinuses also supply intracranial structures (the meninges, in patricular)
Where is the opening of the maxillary air sinus in the nasal cavity? Explain why its anatomy is a cause of nasal disorder.
Its opening is high up on the medial wall of the maxilla. During maxillary congestion, its opening is obstructed thereby affecting its drainage
What is responsible for the change in the shape of the face of a child during the time of the eruption of the permanent teeth and subsequent during puberty?
Rapid growth of the face during infancy and early childhood coincides with the eruption of primary teeth. These changes are more marked after the secondary teeth erupt after 5 – 6 years. Enlargement of the frontal and facial regions is associated with the increase in the size of the paranasal sinuses; growth of the sinuses is responsible for the alteration in the shape of the face.
Why should a patient complaining about toothache be asked about recent upper respiratory tract infections?
The floor of the maxillary sinus lies adjacent to the roots and alveolar processes of the upper teeth (pre-molar & molars). Pain from infection in the maxillary sinus, due to upper respiratory tract infection, is quite indistinguishable from that of dental origin because the teeth & maxillary sinus are both innervated by the maxillary branch of the trigeminal nerve.
Why is it possible for the infection in the frontal sinus to drain into the maxillary sinus?
The drainage of the frontal paranasal sinus is by gravity to the middle meatus. The ostium of the maxillary paranasal sinus which opens into this area is located as such for infection in the frontal sinus to drain straight down into the maxillary sinus.