Oral Cavity

Question 1

What are the associated organs of the digestive system?

Answer 1

Salivary glands, liver, gallbladder and pancreas

Question 2

What are the functions of the the digestive system?>

Answer 2

Ingestion, mastication, deglutition (swallowing), propulsion (peristalsis and segmentation), mechanical digestion, chemical digestion, absorption and defecation

Question 3

What is the oral cavity made up of and what are its functions?

Answer 3

Oral vestibule and the oral cavity proper. The functions are mastication, initiates swallowing and saliva production

Question 4

Describe the boarders of the oral vestibule and oral cavity proper?

Answer 4

Oral vestibule - Space between teeth, gums, lips and cheeks.

Cavity proper - Deep to the teeth and is bounded posteriorly by palatoglossal folds

Question 5

Where is the vermilion border?

Answer 5

It is between the skin of the lips and the mucous membrane. Poorly keratinized skin and is rich in blood vessels.

Question 6

Describe the different regions of teeth in the oral cavity

Answer 6

There are 4, left, right, maxillary and mandibular. Each region has Incisors (2), Canine (1), premolars (2) and molars (3) = 32

Question 7

Name the muscles of mastication and their innervation

Answer 7

Medial pterygoid, lateral pterygoid (only muscle that opens mouth), masseter and temporalis. They are supplied by the mandibular division of the trigeminal nerve.

Question 8

Describe the layers of the buccae (cheek)

Answer 8

Skin, Buccal fat pad, buccopharyngeal fascia, buccinator muscle, buccal glands and mucous membrane.

Question 9

Where does the buccinator muscle attach?

Answer 9

Maxilla (superiorly), mandible (inferior), pterygomandibular raphe (posterior) and orbicularis oris (anteriorly)

Question 10

What is the modiolus?

Answer 10

It is a point of cross over of the buccinator muscle fibres just lateral to the angle of the mouth

Question 11

What is the buccinator muscle innervated by?

Answer 11

Facial nerve (cranial nerve 7)

Question 12

What is the palatine aponeurosis

Answer 12

Formed by periosteum and tendon of tensor veli palatini which supports the soft palate

Question 13

Name the two arches which extend from the uvula to the lateral walls? And what lies between the two arches?

Answer 13

Palatoglossal arch anteriorly and the palatopharyngeal arch (made by the muscle covered by mucosal membrane) In-between is a tonsillar fossa which houses the palatine tonsils.

Question 14

Name the muscles of the soft palate and their function

Answer 14

Palatoglossus and palatopharngeus (pull the palate inferiorly) Levator veli palatini and Tensor veli palatini (elevate the pharynx)

Question 15

Describe the differences between the anterior (2/3rds) and posterior (1/3rd) parts of the tongue

Answer 15

Anterior = Horizontal, oral cavity, involved in taste (facial nerve) and general sensory (mandibular division of trigeminal nerve) .
Posterior - Vertical, oropharynx, taste and general sensation (glossopharyngeal nerve)

Question 16

Name the different papillae in the anterior 2/3rds of the tongue and their function

Answer 16

• Folate papillae, vallate papillae and the fungiform papillae (all have taste buds)
• Filiform papillae which are densely packed anteriorly (touch and temp)

Question 17

How does the tongue sit in the oral cavity? and what are these called?

Answer 17

it is suspended by 4 pairs of skeletal muscles; Genioglossus, hypoglossus, styloglossus (all 3 are hypoglossal nerve) and palatoglossus (vagus).

Question 18

What is the function of the intrinsic and extrinsic muscles of the toungue?

Answer 18

Extrinsic - Changes the position of the tongue (mastication, swallowing and speech).

Intrinsic - Modify the shape

Question 19

What does the mylohyoid muscle form and what is its clinical relevance?

Answer 19

Forms muscular diaphragm which extends between mandible and hyoid bone. It has a free boundary which creates a fascial plane = spread of infection)

Question 20

What are crypts?

Answer 20

Pockets/folds that occur naturally in the tonsils

Question 21

Name the tonsils that form the waldeyer’s ring

Answer 21

Nasal - Tubal x2 and pharyngeal.

Oral - Palatine x2 and lingual

Question 22

What are the functions of the salivary glands?

Answer 22

Lubrication and binding of masticated food, solubilization of dry food, digestion of carbs via alpha amylase and oral hygiene. (facial and glossopharyngeal nerve)

Question 23

Name the different types of salivary glands and where they open into the oral cavity

Answer 23

Parotid gland - serous, opens via the parotid/stensen’s duct opposite 2nd maxillary molar.

Sublingual - Mucous, Opens into the floor of the mouth along the sublingual fold.

Submandibular - mixed mucous and serous. Opens at the sublingual papilla

Question 24

Name the three regions that the pharynx is divided into?

Answer 24

Nasopharynx, oropharynx and laryngopharynx.

Question 25

What are the constrictor muscles of the pharynx

Answer 25

Superior pharyngeal, middle pharyngeal and inferior pharyngeal muscles.

Question 26

What are elevator muscles?

Answer 26

Stylopharyngeus, palatopharyngeus and salpingopharyngeus

Question 27

Where do all the constrictor pharyngeal muscle insert onto?

Answer 27

The pharyngeal raphe

Question 28

What encloses the gap between the occipital bone and superior constrictor is closed by?

Answer 28

Pharyngobasilar fascia

Question 29

What is the sinus of morgagni?

Answer 29

Space between the base of the skull and the upper free boarder of superior constrictor.

Question 30

What is the clinical relevance of Killian’s dehiscence

Answer 30

It is a weak area when the superior pharyngeal constrictor ends. This can prolapse

Question 31

What is Passavant’s Ridge?

Answer 31

It is a mucosal ridge caused by superior pharyngeal constrictor. It encircles the lateral and posterior walls of the nasopharynx

Question 32

What passes through the oropharyngeal triangle?

Answer 32

Stylopharyngeus muscle, glossopharyngeus nerve and stylohyoid ligament

Question 33

Describe the arterial supply of the pharynx

Answer 33

Upper pharynx is supplied by branches of the external carotid artery eg, ascending pharyngeal artery.

Lower pharynx is supplied by pharyngeal branches of the inferior thyroid artery of thyrocervical trunk of subclavian artery

Question 34

Describe the venous and lymphatic drainage of the pharynx

Answer 34

Veins - Drained by pterygoid plexus

Lymph - drainage to retropharyngeal, paratracheal and infrahyoid nodes

Question 35

Where do the palatine tonsils drain too?

Answer 35

Jugulodigastric lymph node when is palpable when inflammed

Question 36

Describe the motor innervation of the pharynx

Answer 36

Stylopharyngeus is supplied by glossopharyngeal nerve, all other constrictor and elevators are supplied by the vagus

Question 37

Describe the sensory supply of the pharynx

Answer 37

Nasopharynx - Maxilary branch of trigerminal nerve.

Oropharynx - glossopharyngeus.

Laryngopharynx - Vagus

Question 38

Describe the process of degluttition (swallowing)

Answer 38

1) Blous pushed to back of oral cavity via mylohyoid and tounge muscles.
2) The palatoglossal and palatopharyngeal arches relax,
3) Tongue tips the bolus through oropharyng isthmus into pharynx via styloglossus.
4) Soft palate stretched and elevated via tensor veli palatini and levator veli palatini
5) Elevated soft palate and passavant’s ridge separate nasopharynx from oropharynx.
6) Pharynx elevated by pharyngeal elevators.
7) Laryngeal inlet is closed (aryepiglottic and thyroepiglottic muscles)
8) Bolus pushed towards oesophagus by pharyngeal constrictors

Question 39

Describe the infant anatomy of the tongue/pharynx

Answer 39

Omega shaped epiglottis, tongue with central groove, fat pads for generation of intra-oral suction, close proximity of soft palate and epigottis.