Session 5: Extra

Question 1

What nerve is in charge of smell sensation

Answer 1

Olfactory nerve (I)
Olfaction (smell)

Question 2

What sensory nerves innervate the nasal cavity

Answer 2

trigeminal (V)
Anterior nasal cavity = V1
Posterior = V2 (involved in sneeze reflex)

Question 3

Facial nerve functions (afferent and efferent

Answer 3

Efferent:

1. parasympathetic innervation to glands like lacrimal gland and salivary glands- submandibular and sublingual
2. Parasympathetic innervation to mucous membranes
3. Facial expression muscles

Afferent
1. Taste from anterior 2/3 tongue (NOT general sensation of tongue which is innervated by V3 for the anterior 2/3 of tongue, glossopharyngeal for everything of the posterior 2/3 of tongue

Question 4

Where does the sympathetic innervation of the nasal cavity/upper airway come from

Answer 4

T1, they mainly innervate the vascular smooth muscle in the blood vessels of upper airway. (the sympa nerves travel along with arteries)

Question 5

Outline the arterial supply and venous drainage of the nasal cavity

Answer 5

Arterial:
1. Superiorly, branches of internal carotid (anterior and posterior ethmoidal arteries) enter the cavity supply the cavity

2.Posteriorly, Branches of external carotid also enter the cavity supply the nasal cavity

Venous:

1. Superiorly, blood is drained into the cranial cavity (cavernous sinus)
2. Posteriorly, blood drains to the pterygoid plexus (between the temporalis muscle and lateral pterygoid)

Question 6

What is the significance of the venous drainage of the nasal cavity

Answer 6

Nasal cavity traps pathogens but then the veins drain it into the brain - flaw in design