6a - The Larynx Flashcards
Larynx function:
-involved in vocalization/phonation
-protection of lower respiratory tract by closing at swallowing
-closing the glottis for straining, defecation, parturition
Parts of upper airway:
*nasopharynx and larynx
-pharyngeal recess
-opening of auditory tubes
-laryngeal entrance
-epiglottis
-vocal folds
-arytenoid cartilages
Parts of the airway in the larynx:
-laryngeal entrance=aditus
-laryngeal vestibule
-glottis
-infraglottic cavity
Cartilages of larynx:
-epiglottic
-arytenoid
-thyroid
-cricoid
Epiglottic cartilage shape:
-single
-median
-leaf-shaped
-most rostral
-elastic
Arytenoid cartilage shape:
-paired
-pyramidal-shaped
-irregular
-mainly hyaline, but corniculate process is elastic
Thyroid cartilage shape:
-single
-trough-shaped
-largest
-body and 2 lateral parts
-hyaline
Cricoid cartilage shape:
-single
-most caudal
-signet ring-shaped
-arch ventrally
-hyaline
With age what kind of cartilage can become partly bony?
-hyaline
>thyroid?
Rostral process (cornu): thyroid cartilage
-articulate with thyrohyoid
Caudal process (cornu): thyroid cartilage
-articulate with cricoid
Caudal thyroid incisure: thyroid cartilage
*only in horses
-covered by crico-thyroid ligament
Arytenoid cartilage parts in horse:
-corniculate process
-muscular process
-vocal process
Corniculate process (horse):
-corniculate tubercule (when covered by mucosa)
-attached to aryepiglottic fold
Muscular process (horse):
-major site of muscular attachment
Vocal process (horse):
-attached to vocal ligament
Arytenoid cartilage in dog:
-*cuneiform process: additional process
>more rostral
Position of larynx:
-remains suspended from cranial base by hyoid apparatus
-moves a hyoid and tongue move
Crico-arytenoid and crico-thyroid joint type in dog:
-synovial
Crico-arytenoid is the:
-most important for regulating glottic opening
Laryngeal ligaments:
-elastic
-hold cartilages together and to other structures
Laryngeal ligaments names
-vestibular and vocal ligaments are less elastic
-crico-thyroid ligament
Laryngeal ligaments and mucosa:
-mucosa covers them to make folds
>vocal fold
>vestibular fold
Laryngeal ventricles formation:
-outpouching of mucosa
*diverticulum
Lateral laryngeal ventricles species:
-horse, dog and pig
Lateral laryngeal ventricles absent in:
-ox and cat
Median laryngeal recess:
-pigs
Laryngeal entrance:
*aditus
-epiglottis
-aryepiglottic folds
-corniculate processes/tubercules
Laryngeal vestibule:
-rostral to glottis
-vestibular folds
-laryngeal ventricles
Glottis:
-arytenoids
-vocal folds (chords)
-glottic cleft=rima glottidis
Infraglottic cavity:
-caudal to glottis
Laryngeal muscles groups:
-extrinsic
-intrinsic
Extrinsic laryngeal muscles:
-sternothyroideus
-thyroheideus
-pharyngeal muscles
Pharyngeal muscles:
-thryopharyngeus
-cricopharyngeus
Intrinsic laryngeal muscles innervation:
*all except one supplied by caudal “recurrent” laryngeal branch of vagus nerve
>not cricothyroideus
Intrinsic laryngeal muscles:
-cricoarytenoideus dorsalis
-cricoarytenoideus lateralis
-arytenoideus transversus
-cricothyroideus
-cricothyroideus
-thyroarytenoideus
Cricoarytenoideus dorsalis:
-abductor of vocal folds
*only one that opens glottis
Cricoarytenoideus lateralis:
-adductor
>closes glottis
Arytenoideus transversus:
-adductor
>closes glottis
Cricothyroideus:
-lengthens/tenses vocal folds
>course adjustment
*only one supplied by cranial laryngeal nerve
Thyroarytenoideus:
-adjusts tension in vocal folds
>fine adjustment
Thyroarytenoideus in horse and dog:
-split into ventricularis and vocalis
