Session 7 - Nose, paranasal Sinuses

Question 1

What is the 4 functions of the nasal cavity?

Answer 1

Warms and humidifies inspired air
Removes and traps pathogens and particulate matter
Sense of smell
Drains and clears the paranasal sinuses and lacrimal ducts

Question 2

Answer 2

Question 3

What is the lining of the olfactory and respiratory region?

Answer 3

Olfactory - Lined by olfactory cells with olfactory receptors

Resp region - pseudostratified epithelium with mucus secreting goblet cells

Question 4

What are the 3 nasal conchae?

Answer 4

superior middle inferior

Question 5

Answer 5

Question 6

What are the 4 pathways for air to flow in the nasal cavity?

Answer 6

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

Question 7

What is the function of the conchae?

Answer 7

• 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

Question 8

Answer 8

SENSE

Question 9

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

Answer 9

a) middle meatus
b) ethmoidal bulla - bulge in lateral wall
c) superior meatus
d) posterior roof
e) inferior meatus
f) inferior meatus

Question 10

How do nerves, vasculature, and lymphatics access the nasal cavity?

Answer 10

via cribiform plate on the roof

Question 11

What structures pass through the sphenopalatine foramen?

Answer 11

Sphenopalatine artery, vein and nerve nerves pass through here.

Question 12

What structures pass through the incisive canal?

Answer 12

Sphenopalatine nerve and descending palatine artery.

Question 13

What is the purpose of the rich blood supply of the nose??

Answer 13

Has rich blood supply to change humidity and temp of inspired air

Question 14

What internal carotid branches supply the nose? How do they reach the nasal cavity?

Answer 14

Anterior and posterior ethmoidal artery
Descend into nasal cavity through cribiform plate

Question 15

What external carotid branches supply the nose?

Answer 15

Sphenopalatine artery
Greater palatine artery
Superior labial artery
Lateral nasal arteries

Question 16

Why is a bleed in the anterior part of the nose more likely than in the posterior portion?

Answer 16

These arteries form anastomoses with each other. Particularly in the anterior portion of nose

Question 17

Where do the veins drain from the nasal cavity? Where do they drain in only some individuals and why is this clinically relevant?

Answer 17

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.

Question 18

Answer 18

Question 19

What nerves supply the ability to smell?

Answer 19

olfactory nerves, which feed into olfactory bulb

Question 20

Describe the general innervation of the septum, lateral walls, and skin of nose

Answer 20

Septum and lateral walls innervated by nasopalatine nerve and nasociliary nerve
Skin of nose innervated by trigeminal nerve

Question 21

What can take place as a result of trauma to the nose? Why does this result in a loss of smell?

Answer 21

• 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).