Week 10: Ear, Nose and Mouth

Question 1

Bones that form the external boundaries of the oral cavity

Answer 1

Maxilla and Mandible

Question 2

Bones that form the internal boundaries of the oral cavity

Answer 2

Palatine process of Maxilla

Horizontal process of the Palatine bone

Question 3

External muscles of the MOUTH and their innervation

Answer 3

Orbicularis m.
Buccinator m.
Masseter m.
Temporalis m.

OB = Facial n. (VII) // MT = Trigeminal n. (V)

Question 4

Floor of the mouth

Answer 4

Myohyloid m., the diaphragm muscle that attaches to the mandible and the hyoid.

Question 5

External muscles of the TONGUE and their innervation

Answer 5

Palatoglossus m.
Styloglossus m.
Hyoglossus m.
Genioglossus m.

All innervated by the hypoglossal n. except for palatoglossus, which is innervated by the vagus n.

Question 6

Internal muscles of the tongue and their innervation

Answer 6

Superior longitudinal
Inferior longitudinal
Transverse
Vertical

All innervated by the hypoglossal n.

Question 7

Teeth in order and quantity

Answer 7

There are 32 teeth in total.
Looking just at the superior part, we have:
4 incisors
2 canines
4 premolars
6 molars

And it is exactly the same inferiorly.

Question 8

Salivary glands

Answer 8

Sublingual gland
Submandibular gland
Parotid gland

Question 9

The parotid duct opens on the

Answer 9

Inside of cheek, close to second molar

Question 10

The skeleton of the external nose is made up of

Answer 10

Nasal bones
Frontal bone
Frontal process of the maxilla

Cartilages: lateral, septal and alar

Question 11

The skeleton of the internal nose (lateral) is made up of

Answer 11

Floor: maxilla and palatine bone
Roof: Ethmoid bone
Lateral wall: Ethmoid, Sphenoidal, Lacrimal bone and inferior concha

Question 12

The skeleton of the internal nose (medial) is made up of

Answer 12

Septal cartilage, ethmoid bone, vomer bone, maxilla and palatine bone.

Question 13

What are some important features of the medial wall of the nasal cavity?

Answer 13

Highly vascularised (temperature)
Ciliated (aids movement of particles)
Mucus producing cells (traps particles)
Sensory area for smell

Question 14

What are the turbinates? What is their function?

Answer 14

Superior, middle and inferior concha. They vibrate as the air passes through the nasal cavity, maintaining the air in contact with the walls of the cavity in order to heat it up and humidify it.

Question 15

Name the 4 sinus and their respective innervation

Answer 15

Frontal, Ethmoid, Sphenoid, Maxillary.

All are innervated by the Trigeminal n. (CNV)

The first three are innervated by the ethmoidal n. from the 1st division (ophthalmic). Maxillary is innervated by the superior alveolar n. from the 2nd division (maxillary).

Question 16

Why do people’s noses get runny when they start to cry?

Answer 16

The nasolacrimal duct opens into the inferior meatus, so when the lacrimal sac cannot contain all the tears, they run through the duct into the nose.

Question 17

Nasal cavity: Name the quadrant and the artery

Answer 17

Posterior quadrant: sphenopalatine a.
Anterior quadrant: facial a. (lateral wall) and labial a. (medial wall)
Superior: ethmoidal a.
Inferior: greater palatine a.

Question 18

Nasal cavity: general innervation

Answer 18

Olfactory n. (CNI)
1st and 2nd division of the trigeminal n. (CNV)

1st division opthalmic = ethmoidal nerves ( superior)
2nd division maxillary = superior alveolar n. (inferior)

Question 19

What is the function of the auditory tube?

Answer 19

It projects anteroinferiorly to nasopharynx and helps to equalize the pressure in the ear.

Question 20

Name the ossicles from the one closer to the membrane to the one most distal to it. What is their function?

Answer 20

Malleus, Incus, Stapes. They transport the vibration from the tympanic membrane through to the inner ear.

Question 21

What is the clinical significance of the auditory tube (Eustachian tube) differences from infants to adults?

Answer 21

It is shorter and more horizontal in infants = more chances of infection in the ear because bacteria can travel through the nose to the ear much easier. Also, hard for infection to drain, due to the angle.

Question 22

The 2 muscles attached to the ossicles are called? What is their function? What is their innervation?

Answer 22

Tensor Tympani (CNV) and Stapedius (CNVII). They’re important to dampen the amplitude of movement of the ossicles when the sound is too loud.

Question 23

The bony labyrinth is filled with ___________ and the membranous labyrinth is filled with ____________.

Answer 23

Perilymph and endolymph

Question 24

Sensory receptors for static equilibrium are located in the?

Answer 24

Saccule and utricle

Question 25

Sensory receptors for dynamic equilibrium (head movement) are located in the?

Answer 25

Ampulla