Lecture 4: Larynx & Pharynx

Question 1

What are the 3 pharyngeal constrictors?

Answer 1

Superior
Middle
Inferior

Question 2

Oropharynx communicates with the nasopharynx via the ___________________; oral cavity via the ______________; and laryngopharynx at the level of the ___________

Answer 2

Pharyngeal isthmus; faucial isthmus; hyoid

Question 3

What nerve is responsible for the efferent component of the laryngeal expiration reflex?

Answer 3

The recurrent laryngeal nerve, intercostal, and abdominal nerves -> control the laryngeal, intercostal and abdominal muscles respectively

Effect of these is abrupt, involuntary EXPIRATORY coughing

Question 4

The pharyngeal plexus is embedded in what type of fascia?

Answer 4

Buccopharyngeal fascia

Question 5

What types of fascia form the anterior and posterior walls of the retropharyngeal space?

Answer 5

Anterior wall = buccopharyngeal fascia

Posterior wall = prevertebral fascia

Question 6

What s the chief sensory nerve to the interior of the larynx?

Answer 6

Internal branch of the superior laryngeal nerve -> supplies GVA sensory fibers to the interior of the larynx and is involved in the cough reflex

• Also supplies PNS fibers (GVE) to the saccule glands of the larynx such as the saccule

Question 7

The laryngeal receptors and afferent fibers of the internal branch of the superior laryngeal nerve represent the afferent component of the _____________________ reflex

Answer 7

Laryngeal expiratory reflex (LER) -> if the internal branch of the superior laryngeal nerve is not functional during the initiation of the protective cough reflex, the protective value of the LER is compromised and there is an increased risk of developing aspiration pneumonia in neurologically impaired patients

Question 8

The laryngopharynx communicates with the oropharynx at the level of the ________; larynx via the ______________; and esophagus at the level of ___________

Answer 8

Hyoid; laryngeal aditus; C6

Question 9

The inferior pharyngeal constrictor is attached laterally to the oblique line of the thyroid cartilage and cricoid cartilage, and posteriorly to the pharyngeal raphe. Its horizontal fibers comprise the ______________ muscle that is used during pharyngeal speech

Answer 9

Cricopharyngeus muscle

Question 10

Explain the third phase of swallowing: pharyngo-esophageal phase

Answer 10

The oropharynx elevates and constricts around the bolus and propels it down the esophagus

Question 11

What 2 muscles are pharyngeal elevators?

Answer 11

Stylopharyngeus

Salpingopharyngeus

Question 12

Explain the second phase of swallowing: oropharyngeal phase

Answer 12

Involves the elevation of the floor of the mouth and tongue in order to push the bolus into the oropharynx

Question 13

The __________________ reflex neurologically protects the upper airway from significant aspiration of food or fluid

Answer 13

Laryngeal cough reflex

Question 14

The pharynx is innervated by the pharyngeal plexus. The plexus receives sensory from what nerve?

Answer 14

Pharyngeal branch of the glossopharyngeal nerve

Question 15

What structures does buccopharyngeal fascia cover?

Answer 15

Buccinator muscle and the pharynx

Question 16

Zenker’s diverticulum is located just above the _______________ muscle

Answer 16

Cricopharyngeus muscle -> just above the upper sphincter of the esophagus UES

**Its a false diverticulum bc it doesnt include all the layers of the esophageal wall

Question 17

The GVA fibers in the pharyngeal plexus convey the afferent information for what reflex?

Answer 17

Gag reflex

Question 18

The nasopharynx communicates with the nasal cavity via the _____________; middle ear cavity via the ______________; and oropharynx via the ________________

Answer 18

Choanae; auditory tube; pharyngeal isthmus

Question 19

What pharyngeal constrictor’s horizontal fibers comprise the cricopharyngeus muscle that is used during pharyngeal speech?

Answer 19

Inferior constrictor

Question 20

_____________ branches of the _______________ nerve convey the sensory components of the gag reflex and _______________ branches of the ______________ nerve mediate the motor response

Answer 20

Pharyngeal branches of glossopharyngeal; pharyngeal branches of vagus

**Helpful way to remember: IN (afferent) by 9, OUT (efferent) by 10

Question 21

What are the 3 phases of swallowing?

Answer 21

1) oral phase
2) Oropharyngeal phase
3) Pharyngo-esophageal phase

Question 22

Explain the first phase of swallowing: oral phase

Answer 22

Synonymous with mastication

Question 23

What nerve innervates all laryngeal muscles except the cricothyroid?

Answer 23

Recurrent laryngeal nerve -> branch of vagus

Question 24

What is the stimulus for the laryngeal expiration reflex (LER)?

Answer 24

Aspiration of material into the laryngeal vestibule

Question 25

What are the boundaries of the pharynx?

Answer 25

Choanae: nasal cavity and nasopharynx

Pharyngeal isthmus: nasopharynx and oropharynx

Faucial Isthmus: oral cavity and oropharynx

Question 26

What is the pharynx innervated by?

Answer 26

Pharyngeal plexus

Question 27

After the recurrent laryngeal nerve crosses the cricothyroid joint and enters the larynx, its called the _____________ nerve. It conveys ____________ fibers to the _______________ muscles

Answer 27

Inferior laryngeal nerve; SVE fibers: Laryngeal muscles except the cricothyroid muscle!

**These fibers originate from the nucleus ambiguus

Question 28

What nerve is responsible for the afferent component of the laryngeal expiration reflex?

Answer 28

Internal branch of the superior laryngeal nerve -> innervates the receptors in the mucosa of the laryngeal mucosa. Afferent s enter the medulla with the vagus nerve and terminate in the vicinity of the nucleus tractus solitarius

Question 29

What are the 4 branches of teh glossopharyngeal nerve (CN IX)?

Answer 29

Pharyngeal nerve to pharyngeal plexus

Sensory (GVA) to mucosa of posterior 1/3 tongue and pharynx

Sensory (SVA) to taste buds of posterior 1/3 of tongue

Motor (SVE) to stylopharyngeus muscle

Question 30

What muscle increases tension on the vocal cords and which decreases the vocal cords?

Answer 30

Cricothyroid = increased tension

Vocalis = decreased tension

Question 31

The stylopharyngeus muscle is a pharyngeal elevator muscle that arises from the styloid process and inserts on the pharyngeal wall between the superior and middle constrictors. What is it innervated by?

Answer 31

SVE fibers of the glossopharyngeal nerve (CN IX)

Question 32

What structures do the superior and inferior laryngeal arteries supply?

Answer 32

Superior thyroid a -> superior laryngeal a -> interior larynx

Inferior thyroid a -> inferior laryngeal a -> thyroid gland and parathyroids

Question 33

What muscle is the only abductor of the vocal cords?

Answer 33

Posterior cricoarytenoid muscle

Question 34

What is the faucial isthmus?

Answer 34

Constricted space between the oral cavity proper and the oropharynx -> formed by palatoglossal and palatopharyngeal folds

Question 35

The pharynx is innervated by the pharyngeal plexus. The plexus receives motor fibers from what nerve?

Answer 35

Pharyngeal branch of the vagus nerve

Question 36

What does the external branch of the superior laryngeal nerve innervate?

Answer 36

Cricothyroid muscle