TBL 27 Flashcards
What demarcates the terminal end of the pharyngeal gut?
The lung bud
Where does the pharyngeal gut extend cranially?
To the oropharyngeal membrane
What does the oropharyngeal membrane separate?
Endoderm-lined pharyngeal gut from stomodeum (primitive oral cavity)
What happens when the oropharyngeal membrane degenerates?
Oropharynx and oral cavity become continuous
What is the fauces and what are its boundaries?
Fauces is the throat, the space between the oral cavity and oropharynx
Superior: soft palate
Inferior: root of the tongue
Lateral: palatoglossal and palatopharyngeal folds
What is the oropharynx continuous with distally?
Laryngopharynx
List the 3 pharyngeal segments
Nasopharynx
Oropharynx
Laryngopharynx
Where is the piriform recess and what can happen with it?
In the laryngopharynx, it can entrap swallowed objects
What’s between the palatopharyngeal and palatoglossal arches?
Tonsillar fossa, filled by palatine tonsil in children but only remnants remain in adults
How are tonsillar crypts formed?
By invagination of nonkeratinized stratified squamous epithelium of the oropharynx at the tonsillar fossa
What connects the nasopharynx with the middle ear?
Pharyngotympanic/auditory tube
What and where are the adenoids?
The pharyngeal tonsil, superior to the bony portion of the auditory tube in mucosa of posterior wall of nasopharynx
What forms the incomplete ring surrounding the pharynx?
Lingual, palatine, and pharyngeal tonsils
Where does lymph from the tonsillar ring drain?
Jugulodigastric / tonsillar lymph nodes, part of the deep cervical lymph nodes that surround the IJV
Describe the salpingopharyngeal fold
It descends from the torus of the auditory tube into the oropharynx, formed by the salpingopharyngeus muscle that blends with the palatopharyngeus
What are the muscles of the inner pharyngeal wall?
Salpingopharyngeus, palatopharyngeus, stylopharyngeus
What are the muscles of the outer pharyngeal wall?
Superior, middle, and inferior pharyngeal constrictors
Where are the pharyngeal constrictor muscles located?
Superior: naso- and oropharynx
Middle and inferior: laryngopharynx
Describe the 1st stage of swallowing
Voluntary, muscles of tongue and soft palate compress bolus against palate and push it into oropharynx
Describe the 2nd stage of swallowing
Involuntary and rapid, soft palate is elevated to seal off the nasopharynx from the oro- and laryngopharynx, suprahyoid and longitudinal pharyngeal muscles contract to shorten/widen pharynx and elevate larynx
Describe the 3rd stage of swallowing
Involuntary, all three pharyngeal constrictors contract to force bolus into esophagus by peristalsis
What traverses the jugular foramen?
CN IX (glossopharyngeal) and CN X (vagus)
What forms the pharyngeal nerve plexus?
Motor fibers of CN X, sensory and motor fibers of CN IX
What do the two ganglia of the pharyngeal nerve plexus do?
Convey somatic sensations from pharyngeal mucosa and posterior tongue to the brain
Convey taste sensations from posterior tongue to the brain
What muscle does CN IX (glossopharyngeal) supply with motor fibers?
Stylopharyngeus
What is derived from the 3rd pharyngeal arch?
Stylopharyngeus muscle
Besides do the 4th and 6th pharyngeal arches produce besides the muscles of the soft palate?
Muscles of the pharyngeal wall (except stylopharyngeus), all innervated by CN X
Hyaline cartilaginous skeleton and associated skeletal muscles of the larynx
What does the thyrohyoid ligament connect?
Thyroid cartilage to hyoid bone, facilitating movement by hyoid muscles
What does the thyrohyoid membrane connect?
Thyroid cartilage and hyoid bone, facilitating movement by hyoid muscles
How is the laryngeal prominence formed?
Anterior midline fusion of plate-like laminae of the thyroid cartilage
Describe the arytenoid cartilages
Arytenoid cartilages are found between posterior separated laminae of the thyroid cartilage and articulate with the superior border of the cricoid cartilage
What differentiates the cricioid cartilage from the thyroid cartilage?
Cricoid forms a complete ring around the laryngeal airway while thyroid does not
Where does the vocal ligament extend?
From arytenoid cartilages to midline junction of thyroid cartilage laminae
Where do ary-epiglottic folds extend?
From arytenoid cartilages to epiglottis
Where is the epiglottis?
Immediately posterior to the root of the tongue
Describe the ary-epiglottic folds
They form the lateral and posterior walls of the laryngeal inlet and are composed of mucosa-covered ary-epiglottic ligaments with ary-epiglottic muscles within the mucosa
What are the walls of the laryngeal inlet?
Anterior: epiglottis
Posterior and lateral: ary-epiglottic folds
Describe the epiglottis
Attaches inferiorly to midline junction of thyroid laminae, composed of hyaline cartilage with elastic fibers to make it flexible
Where is the glottis?
Between the vocal ligaments
What is the space between the laryngeal inlet and vocal cords called?
Laryngeal vestibule
What is the luminal space between the vocal cords and the trachae?
Infraglottic cavity
What regulates the width of the glottis during speaking and respiration?
Laryngeal muscles
What branches off of CN X to innervate the larynx?
Superior laryngeal nerve, recurrent laryngeal nerve
What are the branches of the superior laryngeal nerve?
Internal and external laryngeal nerves
What does the internal laryngeal nerve innervate?
Sensory to mucosa of laryngeal vestibule, middle laryngeal cavity, and superior surface of vocal cords
What does the external laryngeal nerve innervate?
Motor to inferior pharyngeal constrictor and cricothyroid muscle
What does the recurrent laryngeal nerve terminate as?
Inferior laryngeal nerve
What does the inferior laryngeal nerve do?
Provides somatic motor fibers to the laryngeal muscles
What provides somatic motor fibers to the laryngeal muscles?
Inferior laryngeal nerve
What is the somatic sensory distribution of the inferior laryngeal nerve?
Mucosa of the infraglottic cavity
What arteries give off the laryngeal arteries?
Superior and inferior thyroid arteries
How do the superior laryngeal artery and internal laryngeal nerve enter the larynx?
By piercing the thyrohyoid membrane
How do the inferior laryngeal artery and inferior laryngeal nerve reach the larynx?
By coursing along trachea
What laryngeal muscles adduct the vocal cords?
Lateral crico-arytenoid, transverse and oblique arytenoids
What laryngeal muscles abduct the vocal cords?
Posterior crico-arytenoid
What laryngeal muscles tense the vocal cords?
Cricothyroid
What laryngeal muscles relax the vocal cords?
Thyro-arytenoid, vocalis
