Oral Cavity Part 1

Question 1

What are the functions of the digestive system?

Answer 1

• ingestion
• mastication
• deglutition
• propulsion (peristalsis and segmentation)
• mechanical digestion
• chemical digestion
• absorption
• defacation

Question 2

What makes up the oral cavity?

Answer 2

Oral vestibule:
(Borders)
- internal: teeth and gums
- external: lips and cheek

Oral cavity proper:
(Borders):
- anterior/lateral: teeth
- posterior: palatoglossal folds (found hanging off the uvula)

Question 3

What are the functions of the oral cavity?

Answer 3

• mastication
• initiate swallowing
• saliva production (for antimicrobial defence, digestions and lubrication of food bolus)

Question 4

Describe the lips

Answer 4

• externally lined with skin
• has vermillion border (between skin and mucous membrane) of poorly keratinized skin and is rich in blood vessels
• internally lined with oral mucosa with small labial glands that open to oral vestibule

Question 5

Describe the important anatomical features of the mandible

Answer 5

• sublingual fossa (for sublingual gland)
• mylohyoid line (for mylohyoid muscle)
• submandibular fossa for submandibular gland
• retromolar fossa (for attachment of pteryhomandibular raphe)
• lingula of mandible (for sphenomandibular ligmanet)
• mandibular canal/foramen/mental foramen (for inferior alveolar nerve to mental nerve to mandibular teeth)

Question 6

Briefly describe teeth

Answer 6

4 regions:

• left/right
• maxillary/mandible

each region has:

• 2 incisors
• 1 canine
• 2 pre-molars
• 3 molars

total of 32 teeth

Question 7

What are the 4 main muscles of mastication and their supply?

Answer 7

• medial pterygoid
• lateral pterygoid (only one that opens mouth)
• masseter
• temporalis
• all supplied by mandibular division of trigeminal nerve (CN V)

Question 8

Describe the layers of the cheek from superficial to deep

Answer 8

• skin
• buccal fat pad (enhances sucking ability of infant)
• buccopharyngeal fascia
• buccinator muscle
• buccal glands
• mucus membrane

Question 9

Describe the attachments and supply of the buccinator muscle

Answer 9

• superior: maxilla
• inferior: mandible
• posterior: pterygomandibular raphe
• anterior: orbicularis orbis
• innervated by facial nerve (CN VII)

Question 10

Where does the fibres of the buccinator muscle cross-over and what is it called?

Answer 10

it is called modiolus found lateral to the angle of the mouth

Question 11

Describe the palate briefly

Answer 11

• hard palate anteriorly made of bone

- soft palate posteriorly which is musculomembranous

Question 12

Palatine foramen

Answer 12

• incisive foramen for nasopalatine nerve

- greater palatine foramen for greater palatine nerve

Question 13

What are Epstein’s pearls?

Answer 13

clusters of white spots in the midline at the junction of hard and soft palates

Question 14

Describe the palatine arches

Answer 14

• 2 arches that extend from the uvula to the lateral walls
• anteriorly: palatoglossal arch of the palatoglossal muscle
• posteriorly: palatopharyngeal arch of the palatopharyngeus muscle
• there is a tonsillar fossa between arches where the palatine tonsils are

Question 15

Name the muscles of the soft palate and their innervation

Answer 15

• palatoglossus
• palatopharyngeus
• levator veli palatini
• tensor veli palatini
• innervated by the vagus nerve (CN X)

Question 16

What is the tongue and its function?

Answer 16

• a bag of constricted muscles covered in a mucous membrane
• mastication
• deglutition
• taste
• speech
• has furry appearance for gripping food and housing tastebuds

Question 17

Describe the different parts of the tongue

Answer 17

Posterior 1/3:

• vertical part
• in oropharynx
• taste and general sensation (CN IX)

Anterior 2/3:

• horizontal part
• in oral cavity
• taste (CN VII)
• general sensory (CN V3)

where papillae are found:
- foliate papillae
- vallate papillae
- fungiform papillae 
(^ taste buds)
- filiform papillae (touch, temperature)

• anterior and posterior sections separated by sulcus terminalis

Question 18

What are the extrinsic muscles of the tongue and their action?

Answer 18

• genioglossus
• hyoglossus
• styloglossus
• palatoglossus
• function to change the position of the tongue during mastication, swallowing and speech

Question 19

What are the intrinsic muscles of the tongue and their action?

Answer 19

• superior and inferior longitudinal muscle of tongue
• vertical and transverse muscle of the tongue
• modify the shape of the tongue during function

Question 20

What nerves supply the muscles of the tongue?

Answer 20

• hypoglossal nerve (CN XII)

- except palatoglossal which is vagus nerve (CN X)

Question 21

What makes up the floor of the mouth?

Answer 21

• muscular diaphragm of mainly mylohyoid muscle between the mandible and the hyoid bone to support the tongue
• where the fascial plane is located (site of spread of infection)

Question 22

What are the functions of the salivary glands?

Answer 22

• lubrication and binding of masticated food
• solubilization of dry food
• digestion of carbohydrates
• oral hygiene

Question 23

What nerves supply the salivary glands?

Answer 23

• facial nerve (CN VII)

- glossopharyngeal nerve (CN IX)