Lecture 4.5 - Larynx, Pharynx, and Nasal Cavity Flashcards
Where is the larynx? What is it designed for and what does it connect? What does it do?
- anterior of neck and level C3-C6
- designed for voice production
- connects pharynx with trachea
- guards air passages and maintains a patent airway
What is the skeleton of the larynx?
- hyoid bone + 9 cartilages:
- thyroid
- cricoid
- epiglottis
- arytenoid (2)
- corniculate (2)
- cuneiform (2)
What does the epiglottis doe during swallowing?
it passively folds over opening of larynx
What are the 3 ways arytenoid cartilages move to move vocal ligaments?
- sliding on transverse axis
- sliding on anteroposterior axis
- rotating
What happens when arytenoid cartilages slide together? Slide apart?
- together: vocal ligaments come together, closing airway
- apart: vocal ligaments separate, opening airway
What happens when arytenoid cartilages slide anteriorly? posteriorly?
- anteriorly: vocal ligaments relax, decreasing pitch
- posteriorly: vocal ligaments tighten, increasing pitch
What happens when anterior tip of arytenoid cartilages rotate out (abduct)? rotate in (adduct(?
- abduct: vocal ligament separate
- adduct: vocal ligaments come together, but leave a slight gap for whispering
What are the muscles of the larynx?
- cricothyroid
- posterior cricoarytenoid
- lateral cricoarytenoid
- thyroarytenoid
- transverse and oblique arytenoids
What are the functions of the laryngeal muscles and their innervation?
- 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
How can the recurrent pharyngeal nerve be injured? What are the symptoms?
- 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
What is the pharynx? Where is it? What does it conduct air to and what systems is it a part of?
- 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
What are the parts of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
What are the muscles of the nasopharynx?
soft palate
- tensor veli palatini (tenses palate, CN V3)
- levator veli palatini (elevates palate, CN X)
What are the muscles of the oropharynx?
- uvular (elevates uvula, CN X)
- palatopharyngeus (elevates pharynx, depresses palate, CN X)
- palatoglossus (elevates tongue, depresses palate, CN X)
What are the parts of the tonsils?
- lymphatic tissue
- 4 tonsils form a defensive ring around the naso/oropharynx
- pharyngeal (superior)
- palatine (lateral)
- tubal (lateral)
- lingual (inferior)
What are the muscles of the external layer of the pharynx and what do they do?
- superior/middle/inferior constrictor
- constricts wall of pharynx during swallowing.
- peristaltic wave
- inferior constrictor blends in with esophagus
- innervated by vagus via pharyngeal plexus
What are the muscles of the internal layer of the pharynx and what do they do?
- palatopharyngeus, salpingopharyngeus, stylopharyngeus
- elevates pharynx and larynx during swallowing and speaking
- innervated by vagus nerve via pharyngeal plexus except stylopharyngeus (glossopharyngeal n.)
What is the pharyngotympanic tube?
- 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
What does the tensor tympani muscles do?
- it is attached to the malleus
- it contracts to prevent the tympanic membrane from vibrating too much due to loud sounds
What is deglutition?
- 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
What is stage 1 of swallowing?
- 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)
What is stage 2 of swallowing?
- 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
What muscles are used in stage 2 of swallowing?
- palato/salpingo/stylopharyngeus
- genio/mylohyoid
- pharynx elevated
- hyoid protracted, larynx elevated
What is stage 3 of swallowing?
- 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.)
How does the bolus move down the esophagus?
via peristaltic contraction
Where can food get stuck in swallowing?
piriform recess (fossa)
What is the gag reflex?
- 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
What is on the medial wall of the nasal cavity?
septal cartilage, perpendicular plate of ethmoid, vomer
What is on the lateral wall of the nasal cavity? What do they do?
- superior, middle, and inferior nasal concha
- increase surface area of nasal cavity mucosa
- warms and moistens air as it enters the body
What is the nasolacrimal duct?
- begins at the lacrimal foramen in the lacrimal bone
- ends in nasal cavity underneath the inferior nasal concha
What are paranasal sinuses? Name them.
- 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
What is sinusitis?
- infection and/or inflammation of the mucus lining of any sinus(es)
- pain is typically localized to the involved sinus
Where does the sphenoid sinus drain?
- drains into nasal cavity under superior nasal concha
Where do maxillary, frontal, and ethmoid sinuses drain?
- drain into the nasal cavity under the middle nasal concha
Why can infections be spread to other sinuses?
because 3 of them drain into the same place
