Lecture 5: Pharynx and Larynx Flashcards
At what vertebral level does the pharynx end?
C6
What are the 3 phases of swallowing?
- Oral phase: mastification of the food
- Oropharyngeal phase: elevation of the floor of the mouth and tongue in order to push the bolus into the oropharynx
- Pharyngeo-esophageal phase: oropharynx elevates and constricts around the bolus, and propels it down the esophagus
What are the 3 divisions of the pharynx?
- Nasopharynx
- Oropharynx
- Laryngopharynx
The nasopharynx is located posterior to the nasal cavity, how does it communicate w/ the nasal cavity, middle ear cavity, and oropharynx?
Nasal cavity via the choanae
Middle ear cavity via the auditory tube
Oropharynx via the pharyngeal isthmus
What part of the pharynx is the palatine tonsil and palatoglossal fold found in?
Oropharynx
How does the oropharynx communicate w/ the nasopharynx and oral cavity?
Nasopharynx via the pharyngeal isthmus
Oral cavity via the faucial ishtmus
At which levels does the laryngopharynx communicate w/ the oropharynx, via what with the larynx, and the pharynx ends at what vertebral level where it becomes the esophagus?
Oropharynx at the level of the hyoid
Larynx via the laryngeal aditus
Ends at C6 where the pharynx becomes the esophagus
What are the piriform recesses and where are they found?
- Posterior and lateral to the arytenoid cartilages in the laryngopharynx
- Food/liquid is deviated laterally by the epiglottis and flows into these recesses
Function of the stylopharyngeus muscle, where is it found, and what innervates it?
- Elevates the pharynx during deglutination (major elevator)
- Only muscle innervated by glossopharyngeal (IX) nerve
- Arises from styloid process and inserts on pharyngeal wall between the superior and middle constrictors
What are the 3 pharyngal constrictors and their attachments?
- Superior attached laterally to the pterygomandibular raphe
- Middle attahced laterally to the hyoid
- Inferior its horizontal fibers comprise the cricopharyngeus m. (used during pharyngeal speech)
Which pharyngeal constrictor muscle has fibers contributing to the cricopharyngeus muscle; what is this muscle used for?
- Inferior constrictor
- Cricopharyngeus m. used during pharyngeal speech
Zenker’s diverticulae are frequently located where?
Junction of cricopharyngeus and esophageal musculature; an area devoid of a muscular layer
The pharyngeal plexus is found embedded where?
The portion of Buccopharyngeal fascia covering the middle constrictor
The retropharyngeal space is found between what layers and is continous between what levels?
- Between the buccopharyngeal fascia and prevertebral fascia
- Continous from the base of the skull to the mediastinum
- Infections can spread from either region via this space
The SVE fibers to the pharynx and larynx originate where; exit and travel with what nerves and finally provide motor fibers to what plexus?
- Originate in the nucleus ambiguus
- Exit brainstem w/ the spinal accessory nerve, at level of jugular foramen and join the vagus nerve
- Pharyngeal branches of the vagus supply motor fibers to the pharyngeal plexus, which innervates ALL the pharyngeal muscles EXCEPT stylopharyngeus (glossopharynheal CN IX)
The pharyngeal plexus receives GVA and SVE fibers from what nerves; which fibers convey the afferent information for the gag reflex?
- Sensory GVA from the pharyngeal branch of glossopharyngeal n.
- Motor SVE from the pharyngeal branch of the vagus n.
- The GVA fibers in the plexus convey the afferent information for the gag reflex
The pharynx is supplied from branches of which arteries?
- Ascending pharyngeal artery
- Inferior thyroid artery
Which nerves are tested when examining the gag reflex; which are the afferent and efferent portions?
- Pharyngeal branches of the Glossopharyngeal(CN IX) convey the sensory (afferent) component
- Pharyngeal branches of the Vagus (CN X)mediate themotor (efferent) response
IN BY 9, OUT BY 10
What is the GVA and SVA branches of CN IX innervating?
Sensory (GVA) to mucosa of posterior 1/3 tongue and pharynx
Sensory (SVA) to taste buds of posterior 1/3 of tongue
What forms the main supporting element of the laryngeal airway and what vertebral level is it at?
- Cricoid cartilage
- Located at level of C6
What is the significance of the arytenoid cartilages of the larynx?
- Highly mobile in both rotational and transverse directions
- During phonation, they rotate along a vertical axis to control tension of the vocal folds
- During respiration, they slide laterally to open the rima glottidis
What are the valleculae epiglottica; what seprates them; and they are bounded by?
- Cup-shaped recesses between the tongue and epiglottis
- Separeted from one another by the median glossoepiglottic fold
- Bounded laterally by the lateral glossoepiglottic folds
What is the signifiance of the valleculae epiglottica during intubation; what happens as the blade moves forward?
- Blade is often placed in the valleculae epiglottica
- As end of blade is moved forward so is the tongue and epiglottis
- This movement opens the laryngeal aditus and allows for tube to get into the larynx and below the vocal folds
What is the importance of the cricothyroid joint and what nerve sits posterior to it?
- Circular hinge type that functions during increases in pitch by stretching the vocal folds
- The recurrent laryngeal nerve courses posterior to this joint
What does the thyroid membrane extend between and what important neurovasculature pierces this membrane?
- Between the thyroid cartilage and the hyoid bone
- Pierced by the: superior laryngeal artery and the internal laryngeal nerve
What is the function of Cricothyroid muscle; what nerve innervates this muscle; what is it opposed by?
- Increases vocal tension by tilting the thyroid cartlage forward, causing a hinge, and increasing pitch
- Only muscle of larynx innervated by External Branch of the Superior Laryngeal Nerve of the Vagus
- Opposed by the Vocalis muscle (decreases tension)
What muscle is the only abductor of the vocal cords; what innervates this muscle?
- Posterior Cricoarytenoid m.
- Innervated by: recurrent laryngeal branch of Vagus n.
What is the chief sensory nerve to the interior of the larynx; what type of fibers does it supply?
- Internal branch of the Superior Laryngeal nerve from Vagus
- Supplies GVA sensory fibers to the interior of the larynx
- Supplies parasympathetic GVE fibers to the saccule glands of the larynx
After the recurrent laryngeal nerve cross the cricothyroid joint and enters the larynx what is it called; what type of fibers does it convey; what is its function?
- The inferior laryngeal nerve
- Conveys SVE fibers to the laryngeal muscles, excpet the cricothyroid
- These fibers originate from the Nucleus Ambiguus
What are the 2 main arteries supplying the larynx, where do they arise from and what main areas do they supply?
1) Superior thyroid artery produces Superior Laryngeal Arterysupplying the interior of the larynx
2) Inferior thyroid artery produces the Inferior Laryngeal Arterywhich supplies thethyroid gland and parathyroids
What is the laryngeal aditus?
Triangular-shaped opening between the laryngo-pharynx and the larynx
What is the Rima vestibularis?
Elliptical-shaped opening formed by the free edge of the vestibular folds
What ligament forms the vocal folds (cords), where do they extend between, and what are their functions?
- Formed by the vocal ligament
- Extending from the vocal process of the arytenoid cartilages to a point above the inferior notch of the thyroid cartilage
- Primary source of sound during vocalization
- Also act as internal sphincters of the larynx during coughing
What is the Rima Glottidis?
Opening formed by the free margin of the vocal cords
What is the stimulus for the laryngeal expiration reflex (cough reflex); what supplies the afferent and efferent components?
Stimulus: aspiration of material into the laryngeal vestibule
Afferent: the internal branch of the superior laryngeal nerve enter the medulla w/ the vagus nerve and terminate at nucleus tractus solitarius
Efferent: the recurrent branch of laryngeal, intercostal, and abdominal nerves all play a role in the abrupt, involuntary, expiratory, cough
*Remember his story about his dogs anal sphincter closing when he barked. The efferent component of this reflex extends throughout the body!
Explain laryngeal displacement in the newborn and adult humans?
- Research found that there is a gradual, progressive descent of the larynx from newborn to adult position
- Human infants have functional separation of the airway and swallowing function; epiglottis articulates w/ the soft palate. Infants are able to suckle and nasal breath at the same time.
- Adults require neurological airway protection, and rapidly adapting receptors (RARs) in larynx
