oral cavity, larynx, pharynx

Question 1

1. Name the muscles of mastication, and explain how each affects mandibular movement

Answer 1

a. ALL INNERVATED BY CN 5 (trigeminal)
b. Masseter
i. Elevates and protracts mandible
c. Temporalis
i. Elevates and retracts mandible
d. Lateral and medial pterygoids
i. Protract and move mandible side to side
ii. Medial - elevates mandible

Question 2

salivary gland innervation

Answer 2

parasympathetic innervation : CN VII and IX

Question 3

2. Describe the muscles and movements of the tongue.

Answer 3

a. Intrinsic muscles
i. Change shape of tongue
ii. Inside of tongue
b. Extrinsic muscles (most innervated by CN Xll)
i. Genioglossus
1. Stick out
ii. Styloglossus
1. Elevate, retract
iii. Hyoglossus
1. Retract, downward
iv. Palatoglossus
1. Elevate
2. CN X

Question 4

3. Define and describe the structure, location, and innervation pathway of gustatory receptors

Answer 4

gustatory= taste

a. Axons of gustatory cells of the tongue travel through cranial nerves Vll and lX to the brainstem
b. From the brainstem, taste information is sent to the thalamus
c. From the thalamus, taste fibers project to the primary gustatory cortex in the insular cortex

Question 5

4. Explain the anatomy and function of the various structures in the oral cavity, including the tongue, palate, and salivary glands.

Answer 5

a. Tongue
i. Functions
1. Begin mechanical digestion - form bolus
2. Assist in sound production
3. House tastebuds
ii. Taste buds and papillae
1. Taste buds
a. Specialized organs for taste
b. Each is composed of many gustatory cells w taste receptors
2. Papillae
a. Filiform
i. Short and bristle like
ii. Distributed over anterior ⅔ of tongue
iii. Most common
b. Fungiform
i. Contain taste buds
c. Vallate
i. Least numerous, but LARGEST
ii. Contains most of the taste buds
b. Palate
i. Soft palate
1. Posterior ⅓, soft and muscular
2. Uvula = extension of soft palate
a. Closes oropharynx from nasopharynx
b. Helps with gag reflex
ii. Hard palate
1. Anterior ⅔, made of maxilla and palatine bone
c. Salivary glands
i. Intrinsic salivary glands: unicellular, in mouth
ii. Extrinsic salivary glands
1. Parotid
a. Innervated by CN 9 (glossopharyngeal)
b. Facial nerves pierces it, but does NOT innervate it
c. Parotid duct brings saliva to mouth
2. Submandibular
a. Innervated by CN 7 (facial)
b. Produces majority of saliva
c. Submandibular duct carries saliva to mouth
d. Below jaw
3. Sublingual
a. Small ducts under tongue
b. Innervated by CN 7 (facial)
iii. Parasympathetic innervation: CN 7 and 9
iv. Sympathetic innervation: superior cervical ganglia
1. Control saliva production

Question 6

5. Identify the muscles of the pharynx and explain their function in swallowing.

Answer 6

a. Palatal muscles
i. Levator veli palatini
1. Elevate the soft palate when swallowing
2. Innervated by CN 10 (vagus)
3. Close path to nose
ii. Tensor veli palatini
1. Tenses soft palate and opens auditory tube when swallowing or yawning
2. Innervated by CN V (trigeminal)
a. Mandibular branch

Question 7

6. Compare and contrast the functions of the regions of the pharynx.

Answer 7

a. Nasopharynx
i. Continuous with the nasal cavity and superior to the soft palate
ii. Lining: pseudostratified ciliated columnar
iii. Auditory tubes: connect to middle ear
iv. Pharyngeal tonsils
b. Oropharynx
i. Soft palate to epiglottis (hyoid)
ii. Lining: non-keratinized stratified squamous
iii. Palatine tonsils
iv. Lingual tonsils
c. Laryngopharynx
i. Inferior to the hyoid and continuous with the larynx and esophagus
ii. Lining: non-keratinized stratified squamous

Question 8

8. Describe the anatomy and functions of the larynx.

Answer 8

a. Functions
i. Producing vocalizations
ii. Passageway for air
iii. Prevents ingested material from entering the respiratory tract
iv. Participates in both the sneeze and cough reflex
v. Produces sound for speech
b. Anatomy
i. Connects pharynx to trachea
ii. Supported by framework of nine cartilages held in place by ligaments, membranes, and muscles
iii. Thyroid cartilage
1. Largest cartilage
2. Does NOT form complete ring
3. Laryngeal prominence
iv. Cricoid cartilage
1. Inferior to thyroid cartilage
2. Full ring
3. Holds larynx open
v. Epiglottis
1. Elastic cartilage
2. Function: swallowing causes the epiglottis to close the opening to the larynx
vi. Cartilage involved in sound production
1. Arytenoid cartilage, corniculate cartilage, cuneiform cartilage
vii. Vocal folds
1. Vocal ligaments covered by a mucous membrane
viii. Glottis
1. Opening between the vocal folds

Question 9

9. Describe the actions of muscles of the larynx on the vocal cords.

Answer 9

a. Extrinsic muscles
i. Suprahyoid and infrahyoid muscles
b. Sound production dependent on sinuses
c. By moving joints between cartilages, length and tension on vocal cords change so we produce sounds with different pitches - muscles changes the tension to make different sounds
i. Shorter, tenser cord - higher pitch
ii. Longer, looser cord - lower pitch