Session 7 - Nose, paranasal Sinuses Flashcards
What is the 4 functions of the nasal cavity?
Warms and humidifies inspired air
Removes and traps pathogens and particulate matter
Sense of smell
Drains and clears the paranasal sinuses and lacrimal ducts
What is the lining of the olfactory and respiratory region?
Olfactory - Lined by olfactory cells with olfactory receptors
Resp region - pseudostratified epithelium with mucus secreting goblet cells
What are the 3 nasal conchae?
superior middle inferior
What are the 4 pathways for air to flow in the nasal cavity?
Inferior meatus – between inferior concha and floor of nasal cavity
Middle meatus – lies between inferior and middle conchae
Superior meatus – lies between middle and superior conchae
Spheno-ethmoidal recess – superior and posterior to superior concha
What is the function of the conchae?
- increase SA of nasal cavity, allowing more air to come into contact with cavity walls.
- Disrupts fast laminar flow of air making it slow and turbulent, giving more time for humidification
SENSE
Where are the openings of the following found:
a) paranasal sinuses
b) middle ethmoidal bulla
c) posterior ethmoidal sinus
d) Sphenoid sinus
e) nasolacrimal duct
f) eustachian tube
a) middle meatus
b) ethmoidal bulla - bulge in lateral wall
c) superior meatus
d) posterior roof
e) inferior meatus
f) inferior meatus
How do nerves, vasculature, and lymphatics access the nasal cavity?
via cribiform plate on the roof
What structures pass through the sphenopalatine foramen?
Sphenopalatine artery, vein and nerve nerves pass through here.
What structures pass through the incisive canal?
Sphenopalatine nerve and descending palatine artery.
What is the purpose of the rich blood supply of the nose??
Has rich blood supply to change humidity and temp of inspired air
What internal carotid branches supply the nose? How do they reach the nasal cavity?
Anterior and posterior ethmoidal artery
Descend into nasal cavity through cribiform plate
What external carotid branches supply the nose?
Sphenopalatine artery
Greater palatine artery
Superior labial artery
Lateral nasal arteries
Why is a bleed in the anterior part of the nose more likely than in the posterior portion?
These arteries form anastomoses with each other. Particularly in the anterior portion of nose
Where do the veins drain from the nasal cavity? Where do they drain in only some individuals and why is this clinically relevant?
drain into pterygoid plexus, facial vein or cavernous sinus
In some individuals, some nasal veins join with sagittal sinus, a potential pathway from infection to spread from nose into cranial cavity.
What nerves supply the ability to smell?
olfactory nerves, which feed into olfactory bulb
Describe the general innervation of the septum, lateral walls, and skin of nose
Septum and lateral walls innervated by nasopalatine nerve and nasociliary nerve
Skin of nose innervated by trigeminal nerve
What can take place as a result of trauma to the nose? Why does this result in a loss of smell?
- Fractured cribiform plate can penetrate meningeal linings of brain, causing leakage of CSF. Exposing brain to outside environment increases risk of meningitis, encephalitis and brain abscesses.
- Olfactory bulb lies on cribiform plate and can be damaged irreversibly, resulting in loss of smell (anosmia).
