Nasal and Oral Cavities

Question 1

Where is the tongue positioned?

Answer 1

The tongue fills the floor of the mouth and is attached to the posterior of the ramus of the mandible and hyoid bone. The surface of the anterior ⅔ of the tongue lies against the palate and the posterior ⅓ against the posterior wall of the oropharynx.

Question 2

What is the function of the tongue?

Answer 2

The tongue is covered with special sensory cells to detect sugar, salt, sour, bitter and umami.

Question 3

What is the tongue’s sensory taste sensation innervated by?

Answer 3

Taste sensation from the anterior ⅔ of the tongue is carried in the facial nerve and the posterior ⅓ in the glossopharyngeal nerve.

Question 4

What is the tongue’s general sensation innervated by?

Answer 4

The tongue also has general sensation: touch, vibration, hot, cold etc and these sensations are carried in the trigeminal nerve from the anterior ⅔ and the glossopharyngeal in the posterior ⅓.

Question 5

What are is the motor function of the tongue innervated by?

Answer 5

The muscles of the tongue are supplied by the hypoglossal nerve.

Question 6

What is the blood supply to the tongue?

Answer 6

The tongue’s blood supply is mostly from the lingual artery (a branch of the external carotid artery).

Question 7

What is the palatine tonsil?

Answer 7

A consolidation of lymphoid tissue which samples organisms which may try to enter the body via the mouth or nose.

Question 8

Where is the palatine tonsil located?

Answer 8

Located on the lateral wall of the oropharynx beyond the posterior third of the tongue. The lateral surface is covered by a fibrous capsule, and is separated from the superior constrictor of the tonsillar bed by loose areolar connective tissue.

Question 9

What are the palatoglossal and Palatopharyngeal muscles?

Answer 9

They form the palatoglossal and palatopharyngeal folds which lie in front and behind the tonsillar fossa respectively.

Question 10

What is a Tonsillectomy?

Answer 10

A surgical procedure in which both palatine tonsils are fully removed from the back of the throat. The procedure is mainly performed for recurrent throat infections and obstructive sleep apnea.

Question 11

What are the Adenoids?

Answer 11

Adenoids are glands located in the roof of the mouth, behind the soft palate where the nose connects to the throat. The adenoids produce antibodies, or white blood cells, that help fight infections. Typically, the adenoids shrink during adolescence and may disappear by adulthood.

Question 12

What are basics of the teeth?

Answer 12

Standardised mouth contains 32 teeth. In the adult mouth there are two incisors anteriorly, one canine, two premolars on each side, top and bottom.

Question 13

What is the roof of the mouth?

Answer 13

The palate which separates the oral and nasal cavities.

Question 14

What is the hard palate?

Answer 14

The anterior two thirds of the palate which is formed by the palatine processes of the maxillary bones anteriorly and the horizontal plates of the palatine bones posteriorly.

Question 15

What is the soft palate?

Answer 15

The posterior third of the palate is muscular. The tensor palatine, levator palatine, musculus uvuli, palatoglossus and palatopharyngeus form the soft palate.

Question 16

What is the function of the soft palate?

Answer 16

It’s function is to control the orifice between the nasal and oral parts of the pharynx. Elevation of the soft palate closes the orifice and this occurs during swallowing to stop reflux of food into the nasopharynx and during phonation to allow the production of explosion consonants.

Question 17

What is the Eustachian tube?

Answer 17

A cartilaginous and bony tube that connects the middle ear to the nasopharynx. It acts to equalise the pressure of the middle ear to that of the external auditory meatus.

Question 18

What is the nasal cavity?

Answer 18

Nasal cavity lies above the palate and communicates with the nasopharynx posteriorly. The bony sinuses, middle ear and tear duct all join the nasal cavity.

Question 19

What are the functions of the nasal cavity?

Answer 19

Warms and humidifies the inspired air.
Removes and traps pathogens and particulate matter from the inspired air.
Responsible for sense of smell.
Drains and clears the paranasal sinuses and lacrimal ducts

Question 20

What areas is the nasal cavity divided into?

Answer 20

Vestibule – the area surrounding the anterior external opening to the nasal cavity.
Respiratory region – lined by a ciliated psudeostratified epithelium, interspersed with mucus-secreting goblet cells.
Olfactory region – located at the apex of the nasal cavity. It is lined by olfactory cells with olfactory receptors.

Question 21

What is the nasal septum?

Answer 21

The bone and cartilage in the nose that separates the nasal cavity into the two nostrils. The anterior part of the nasal septum is cartilage whereas the posterior is bony (vomer).

Question 22

What are the nasal conchae?

Find them on a diagram

Answer 22

Projecting out of the lateral walls of the nasal cavity are curved shelves of bone, the nasal conchae. The are three conchae – inferior, middle and superior.

Question 23

What is the function of the nasal conchae?

Answer 23

To increase the surface area of the nasal cavity – this increases the amount of inspired air that can come into contact with the cavity walls. They also disrupt the fast, laminar flow of the air, making it slow and turbulent. The air spends longer in the nasal cavity, so that it can be humidified.

Question 24

What are the nasal meatuses?

Answer 24

The nasal conchae create four pathways for the air to flow. These pathways are called meatuses:
Inferior meatus – between the inferior concha and floor of the nasal cavity.
Middle meatus – between the inferior and middle concha.
Superior meatus – between the middle and superior concha.
Spheno-ethmoidal recess – superiorly and posteriorly to the superior concha (the olfactory nerve passes through here to the brain).

Question 25

What is the nasolacrimal duct?

Answer 25

Acts to drain tears from the eye. It opens into the inferior meatus.

Question 26

What is the bulla ethmoidalis?

Answer 26

A bulge in the lateral wall formed by the middle ethmoidal sinus itself whereby the middle ethmoidal sinuses empty out into the nasal cavity.

Question 27

What is the Hiatus semilunaris?

Answer 27

A crescent-shaped groove on the lateral walls of the nasal cavity. This is where the frontal, maxillary and anterior ethmoidal sinuses open into the middle meatus so that they can drain into the nasal cavity.

Question 28

Where do each of the paranasal sinuses join the nasal cavity?

Answer 28

Frontal, maxillary and anterior ethmoidal sinuses open into the middle meatus.
Middle ethmoidal sinuses empty out onto the ethmoidal bulla.
Posterior ethmoidal sinuses open out at the level of the superior meatus.
Sphenoid sinus drains onto the posterior roof (not the lateral walls of the nasal cavity).

Question 29

What are the 4 paranasal sinuses and find them on a diagram?

Answer 29

Air-filled extensions of the respiratory part of the nasal cavity. There are four paired sinuses, named according to the bone in which they are located; maxillary, frontal, sphenoid and ethmoid. Lined with respiratory mucosa.

Question 30

What is the function of the paranasal sinuses?

Answer 30

It is thought that they may contribute to the humidifying of the inspired air. They also reduce the weight of the skull.

Question 31

Where is the frontal sinus?

Answer 31

Most superior in location, found under the forehead. Always triangular-shaped. They drain into the nasal cavity via the frontonasal duct, which opens out at the hiatus semilunaris on the lateral wall.

Question 32

Where is the maxillary sinus?

Answer 32

The largest of the sinuses. It is located laterally and slightly inferiorly to the nasal cavities. It drains into the nasal cavity at the hiatus semilunaris, underneath the frontal sinus opening. This is a potential pathway for spread of infection – fluid draining from the frontal sinus can enter the maxillary sinus.

Question 33

Where is the sphenoid sinus?

Answer 33

Lies at the level of the spheno-ethmodial recess. The sphenoid sinuses drain out onto the roof of the nasal cavity. The pituitary gland can be surgically accessed via passing through the nasal roof, into the sphenoid sinus and through the sphenoid bone.

Question 34

Where is the ethmoid sinus?

Answer 34

There are 3 ethmoid sinuses. They empty into the nasal cavity at different places:
Anterior – Hiatus semilunaris
Middle – Ethmoid bulla
Posterior – Superior meatus

Question 35

Why are children born with a cleft palate at risk of ear problems?

Answer 35

Children born with a cleft palate may not have function in the soft palate muscles to open the Eustachian tube during swallowing. They will be at risk of middle ear infections and conductive deafness.

Question 36

What problems do enlarged adenoids cause?

Answer 36

Persistent enlargement of the adenoids due to repeated throat infections often leads to middle ear infection and conductive deafness.

Question 37

What is a grommet and how is it used?

Answer 37

Treatment for enlarged adenoids: remove them and create an artificial passage into the middle ear to ‘bypass’ the diseased Eustachian tube. This is done by placing a tiny plastic tube through the ear drum directly into the middle ear cavity (a grommet).

Question 38

What is different about the maxillary sinus?

Answer 38

Majority of the nasal sinuses communicate with the nasal cavity at their lowest point. But the maxillary sinus communication point is near the top of the sinus. This results in less efficient drainage of mucous and an increased incidence of maxillary sinusitis. Getting the patient to lie on their side will aid drainage and therefore recovery.