Lecture 4.5 - Larynx, Pharynx, and Nasal Cavity

Question 1

Where is the larynx? What is it designed for and what does it connect? What does it do?

Answer 1

• anterior of neck and level C3-C6
• designed for voice production
• connects pharynx with trachea
• guards air passages and maintains a patent airway

Question 2

What is the skeleton of the larynx?

Answer 2

• hyoid bone + 9 cartilages:
• • thyroid
• • cricoid
• • epiglottis
• • arytenoid (2)
• • corniculate (2)
• • cuneiform (2)

Question 3

What does the epiglottis doe during swallowing?

Answer 3

it passively folds over opening of larynx

Question 4

What are the 3 ways arytenoid cartilages move to move vocal ligaments?

Answer 4

1. sliding on transverse axis
2. sliding on anteroposterior axis
3. rotating

Question 5

What happens when arytenoid cartilages slide together? Slide apart?

Answer 5

• together: vocal ligaments come together, closing airway

- apart: vocal ligaments separate, opening airway

Question 6

What happens when arytenoid cartilages slide anteriorly? posteriorly?

Answer 6

• anteriorly: vocal ligaments relax, decreasing pitch

- posteriorly: vocal ligaments tighten, increasing pitch

Question 7

What happens when anterior tip of arytenoid cartilages rotate out (abduct)? rotate in (adduct(?

Answer 7

• abduct: vocal ligament separate

- adduct: vocal ligaments come together, but leave a slight gap for whispering

Question 8

What are the muscles of the larynx?

Answer 8

• cricothyroid
• posterior cricoarytenoid
• lateral cricoarytenoid
• thyroarytenoid
• transverse and oblique arytenoids

Question 9

What are the functions of the laryngeal muscles and their innervation?

Answer 9

• function: modulate voice and airflow (posterior cricoarytenoid is only muscle that abducts)
• innervation: vagus nerve (CN X)
• • external laryngeal br. of CN X to criocythyroid
• • recurrent laryngeal of br. of CN X to all others

Question 10

How can the recurrent pharyngeal nerve be injured? What are the symptoms?

Answer 10

• the recurrent laryngeal n. may be injured due to inflammation of surgery on structures around it in the neck (thyroid gland, trachea, esophagus)
• injury results in high pitched, noisy respiration, and breathy voice

Question 11

What is the pharynx? Where is it? What does it conduct air to and what systems is it a part of?

Answer 11

• the muscular tube that extends from base of cranium
• to inferior border of cricoid cartilage (anterior) and inferior border of C6 (posterior(
• conducts air to the larynx, trachea, and lungs (respiratory system)
• part of digestive system which pushes food into esophagus

Question 12

What are the parts of the pharynx?

Answer 12

• nasopharynx
• oropharynx
• laryngopharynx

Question 13

What are the muscles of the nasopharynx?

Answer 13

soft palate

• tensor veli palatini (tenses palate, CN V3)
• levator veli palatini (elevates palate, CN X)

Question 14

What are the muscles of the oropharynx?

Answer 14

• uvular (elevates uvula, CN X)
• palatopharyngeus (elevates pharynx, depresses palate, CN X)
• palatoglossus (elevates tongue, depresses palate, CN X)

Question 15

What are the parts of the tonsils?

Answer 15

• lymphatic tissue
• 4 tonsils form a defensive ring around the naso/oropharynx
• pharyngeal (superior)
• palatine (lateral)
• tubal (lateral)
• lingual (inferior)

Question 16

What are the muscles of the external layer of the pharynx and what do they do?

Answer 16

• superior/middle/inferior constrictor
• constricts wall of pharynx during swallowing.
• peristaltic wave
• inferior constrictor blends in with esophagus
• innervated by vagus via pharyngeal plexus

Question 17

What are the muscles of the internal layer of the pharynx and what do they do?

Answer 17

• palatopharyngeus, salpingopharyngeus, stylopharyngeus
• elevates pharynx and larynx during swallowing and speaking
• innervated by vagus nerve via pharyngeal plexus except stylopharyngeus (glossopharyngeal n.)

Question 18

What is the pharyngotympanic tube?

Answer 18

• connects pharynx to tympanic cavity of middle ear to equalize air pressure so tympanic membrane can vibrate freely
• pharyngeal opening is passively held shut - needs active opening by the contractions of tensor veli and levator veli palatini during swallowing or yawning

Question 19

What does the tensor tympani muscles do?

Answer 19

• it is attached to the malleus

- it contracts to prevent the tympanic membrane from vibrating too much due to loud sounds

Question 20

What is deglutition?

Answer 20

• act of swallowing
• the process whereby a bolus (masticated morsel of food) is transferred from the oral cavity through the pharynx and esophagus into the stomach

Question 21

What is stage 1 of swallowing?

Answer 21

• voluntary
• food bolus pushed against palate via tongue
• bolus squeezed into oropharynx via tongue and soft palate
• tensor veli palitini (tensor soft palate, makes it rigid enough for the tongue to press against it)
• styloglossus
• palatoglossus (elevate tongue against palate)

Question 22

What is stage 2 of swallowing?

Answer 22

• involuntary
• soft palate is elevated, sealing off the nasopharynx
• levator veli palatini (elevates the palate)
• uvular (elevates the uvula)
• palatoglossus (elevates back of tongue to continue pushing bolus down the pharynx)
• the pharynx is widened and shortened to receive food bolus

Question 23

What muscles are used in stage 2 of swallowing?

Answer 23

• palato/salpingo/stylopharyngeus
• genio/mylohyoid
• pharynx elevated
• hyoid protracted, larynx elevated

Question 24

What is stage 3 of swallowing?

Answer 24

• involuntary
• sequential contraction of all 3 constrictor muscles forces food inferiorly into the esophagus
• superior/middle/inferior constrictor
• epiglottis closes the larynx (pressure of food against the epiglottis, aryepiglottic m., innervated by vagus n.)

Question 25

How does the bolus move down the esophagus?

Answer 25

via peristaltic contraction

Question 26

Where can food get stuck in swallowing?

Answer 26

piriform recess (fossa)

Question 27

What is the gag reflex?

Answer 27

- touching posterior 1/3 of tongue, soft palate, or pharynx (general sensation transmitted in IX) elicits reflex - causes contraction of pharynx muscle (somatic motor innervated by X) - prevents anything from entering throat, prevents choking; can be used intentionally to induce vomiting

Question 28

What is on the medial wall of the nasal cavity?

Answer 28

septal cartilage, perpendicular plate of ethmoid, vomer

Question 29

What is on the lateral wall of the nasal cavity? What do they do?

Answer 29

- superior, middle, and inferior nasal concha - increase surface area of nasal cavity mucosa - warms and moistens air as it enters the body

Question 30

What is the nasolacrimal duct?

Answer 30

- begins at the lacrimal foramen in the lacrimal bone | - ends in nasal cavity underneath the inferior nasal concha

Question 31

What are paranasal sinuses? Name them.

Answer 31

- mucus-lined pockets named for the bone they're in: - - frontal, ehtmoid, sphenoid, maxillary sinus - they all have openings into the nasal cavity, which is a source of infection

Question 32

What is sinusitis?

Answer 32

- infection and/or inflammation of the mucus lining of any sinus(es) - pain is typically localized to the involved sinus

Question 33

Where does the sphenoid sinus drain?

Answer 33

- drains into nasal cavity under superior nasal concha

Question 34

Where do maxillary, frontal, and ethmoid sinuses drain?

Answer 34

- drain into the nasal cavity under the middle nasal concha

Question 35

Why can infections be spread to other sinuses?

Answer 35

because 3 of them drain into the same place