1. Oral Cavity, Pharynx and Oesophagus

Question 1

Name the muscles of mastication

Answer 1

Temporalis; Masseter; Lateral pterygoid, Medial Pterygoid

Question 2

Name the Action of the temporalis

Answer 2

Elevation of mandible (jaw) ; opens/closes.

Retracts mandible - moving it backwards

Question 3

Name the actions of the masseter

Answer 3

Elevates the jaw and protracts (moves jaw anteriorly)

Question 4

Name the action of the lateral pterygoid

Answer 4

Protracts and adducts and abducts mandible

Question 5

Name the actions of the medial pterygoid

Answer 5

Protracts, adducts and abducts

Question 6

What are the muscles of mastication innervated by?

Answer 6

Innervated by the mandibular division of the trigeminal nerve - CNV3 (the mandibular division is the 3rd of 3 divisions of the trigeminal nerve, which is cranial nerve 5. )

Question 7

Name the muscles of facial expression (also involved in speech)

Answer 7

Orbicularis Oris:: The sphincter of the lips is called the orbicularis oris, because it ‘orbits’ the mouth

Buccinator muscle- cheeck muscle: positioning a bolus of food between the molar teeth for grinding (but the movements at the TMJare caused by muscles of mastication

Question 8

What are the muscles of facial expression innervated by?

Answer 8

CN7- Facial nerve

Question 9

How many teeth do we have? what are they called?

Answer 9

Permanent: 4 quadrants x 8 teeth/quadrant

2 incisors
1 canine/cuspid
2 premolars/bicuspids
3 molars

32 teeth

PRIMARY (deciduous) 
4 quadrants x 5 teeth:
2 incisors
1 canine
2 molars
= 20 teeth

Question 10

Explain the motor innervation of the tongue

Answer 10

MOTOR:
The muscles of the tongue (intrinsic and intrinsic) are innervated by the HYPOGLOSSAL NERVE (CN12)
EXCEPT the palatoglossus, which is innervated by the VAGUS NERVE (CNX). This muscle is also a muscle of the palate and most palate muscles are innervated by the vagus nerve

Question 11

Explain sensory innervation of the tongue

Answer 11

Sensory innervation of the tongue includes general sensation (touch, pain, temperature) and hthe special sensation of taste.

Anterior 2/3 of the tongue:

• General sensation: MANDIBULAR DIVISION OF TRIGEMINAL NERVE (CNV3)
• Taste: FACIAL NERVE (CN7)

Posterior 1/3 of tongue
General Sensation: Glossopharyngeal Nerve (CN9)
Taste: Glossopharyngeal nerve again!

Question 12

What are the intrinsic tongue muscles?

Answer 12

These are within the tongue:

Longitudinal, transverse, vertical= and change the shape of the tongue

Question 13

Name the extrinsic tongue muscles

Answer 13

BONE TO TONGUE

• Genioglossus; Depress and protrudes the tongue
• Hyoglossus: depress and retract the tongue
• Styloglossus: Elevate and retract the tongue
• Palatoglossus- Elevates posterior tongue, closes oropharyngeal isthmus and aids in initiation of swallowing.

Question 14

What are the salivary glands in the oral cavity?

Answer 14

Parotid, submandibular, sublingual, many small intrinsic.

Produce 1-1.5 l of saliva!!

Question 15

How do we stimulate salivary gland secretions?

Answer 15

The thought, sight, smell, presence of food stimulates the PARASYMPATHETIC NERVOUS SYSTEM (or the craniosacral division of the autonomic nervous system) to stimulate saliva production and secretion.

Question 16

What stimulates the Parotid Salivary gland?

Answer 16

CN9 (glossopharyngeal).
preganglionic nucleus is in the medulla
Ganglion: Otic

Question 17

What stimulates the submandibular and sublingual salivary glands?

Answer 17

CN7 (facial nerve)
Preganglionic nucleus: in the pons
Ganglion: submandibular

Question 18

What are the functions of the pharynx and oesopahgus?

Answer 18

Swallowing, propulsion of food to stomach
Pharynx also a part of the upper respiratory tract for breathing
Secretions (mucous) protect the mucosa
Upper and lower oesophageal sphincters - prevent air from entering the oesophagus and reflux of stomach contents

Question 19

What are the three parts of the pharynx?

Answer 19

Nasopharynx
Oropharynx
Laryngopharynx

Question 20

What level does the pharynx run?

Answer 20

from BASE OF SKULL to C6/7 vertebrae

Question 21

What is the sensory innervation of the pharynx?

Answer 21

CN9- GLOSSOPHARYNGEAL

CNX- VAGUS

Question 22

What are the muscles of the pharynx? and what are they innervated by?

Answer 22

Superior, middle, inferior pharyngeal constrictors
Inferior constrictor include cricopharyngeus (upper oesophageal sphincter UOS or UES)

Palatopharyngeus

All innervated by CNX except

Stylopharyngeus - innervated by CN9

Question 23

What are the muscles of the soft palate?

What is their innervation

Answer 23

LEVATOR VELI PALATINE

TENSOR VELI PALATINE- elevate palate during swallowing to prevent food moving into the nasopharynx.

PALATOGLOSSUS, PALATOPHARYNGEUS- depress palate and narrow opening to the oropharynx- enable you to chew and breathe at the same time.

All innervated by CNX (vagus)
Except tensor veli palatine (innervated by mandibular division of trigeminal nerve CNV3)

Question 24

The Oesophagus

Answer 24

Skeletal, mixed and smooth muscle, innervated by CNX (Vagus nerve)
Mucus from glands protect the mucosa
Constrictions of the oesophagus at the origin (UOS), arch of aorta, diaphragm, LOS - pathology is more likely at these areas

Question 25

Describe the anatomical relationship of the pharynx

Answer 25

In the posterior mediastinum: it is anterior to the descending aorta.
In the abdominal cavity it is posterior to the left lober of the liver.

Question 26

Explain the stages of sWhat are the stages of swallowing?

Answer 26

VOLUNTARY (oral/buccal) phase

Pharyngeal phase

Question 27

Explain the voluntary phase of swallowing

Answer 27

Tongue moves bolus of food into the oropharynx

Question 28

Explain the pharyngeal phase of swallowing

Answer 28

Soft palate is elevated to close off the nasopharynx

Larynx: Elevated, moves anterior (suprahyoid muscles)- this opens the laryngopharynx

Elevation of the pharynx by the stylopharyngeus, palatopharyngeus.

The larynx is protected by contraction of the muscles around the laryngeal inlet to narrow the inlet, epiglottis pulled posteriorly- by the aryepiglottic and thyroepiglottic muscles
Vocal and vestibular folds are ADDUCTED by the lateral and transverse cricoarytenoids

The UOS RELAXES to allow bolus into the oesophagus
Waves of relaxation and contraction of the pharyngeal constrictors from superior to inferior moves bolus inferiorly.

CONTROL- Bolus contracting soft palate and oropharynx initiating swallowing reflex

The swallowing centre in the medulla coordinates motor neurons in pons, medulla, and upper cervical cord.

Question 29

Explain the oesophageal phase of swallowing

Answer 29

Waves of peristalsis (contraction, relaxation) propels bolus from superior to inferior to stomach.
Controlled via swallowing centre and locally via the enteric nervous system.
UOS, LOS tonically contracted, relax to let bolus pass.

Question 30

What are the pressures of the UES and LOS??

Answer 30

UOS: 60mmHg

LOS: 20-40mmHg

Question 31

What are some oesophageal Disorders?

Answer 31

Oesophageal Reflux and Complications
Achalasia- poor relaxation of LOS, loss of peristalsis, simultaneous contraction of full length of oesophagus

Scleroderma causes fibrosis of the oesophagus

Tumours

Question 32

What are the parts of the teeth?

Answer 32

CROWN, NECK, ROOT

The teeth are secured by gomphoses (fibrous joints of the ‘peg in socket’ variety) to the superior alveolar process of the maxilla and the inferior alveolar process of the mandible.
The teeth are living structures, with a rich neurovascular supply. The SUPERIOR ALVEOLAR nerves, branches of the maxillar division of the trigeminal nerve (CNV2) innervate the MAXILLARY teeth.
The INFERIOR alveolar nerve, a brance of the mandivular division (CNV3) of the trigeminal nerve, innervates the MANIDBULAR TEETH