Card Set Information

2011-11-28 17:54:19
Larynx HN

Larynx HN
Show Answers:

    • in the anterior part of the neck at the level of the bodies of the C3-C6 vertebrae
    • connects the inferior part of the pharynx with the trachea
    • serves as a valve or sphincter to guard the air passages and maintain a patent airway, especially during swallowing
    • phonating mechanism that is designed for voice production
  2. Laryngeal Skeleton
    • consists of 9 cartilages
    • joined by ligaments and membranes.
    • Three of the cartilages are single
    • (thyroid, cricoid, and epiglottic)
    • three are paired (arytenoid, corniculate, and cuneiform).
  3. thyroid cartilage
    • (hyaline cartilage)
    • consists of right & left
    • laminae, a superior cornu which projects up to the hyoid bone and an inferior cornu which projects down to articulate with the cricoid cartilage at a synovial hinge-
    • type joint, the cricothyroid joint.
  4. cricothyroid joint type
    synovial hinge
  5. cricoid (hyaline cartilage)
    • only complete ring of cartilage in the respiratory system
    • consists of an arch in front and a lamina or plate behind
  6. Glottis
  7. epiglottic
    • (yellow elastic cartilage),
    • attached to the posterior surface of the thyroid cartilage by the thyroepiglottic ligament
  8. arytenoids
    • (paired hyaline cartilages),
    • set on top of the cricoid lamina,
    • pyramidal-shaped with bases forming synovial joints with the cricoid lamina,
    • arytenoid cartilages glide medial or lateral, forward or backward, and rotate on cricoid lamina,
    • each has two processes: a muscular process which projects laterally and has two muscles, the lateral and posterior cricoarytenoids, attached to it, and a vocal process which projects forward, the vocal ligament and vocalis muscle attach here.
  9. thyrohyoid membrane
    attaches the larynx to the hyoid bone
  10. cricotracheal ligament
    attaches the larynx to the trachea (do not worry about this one)
  11. quadrangular or aryepiglottic membrane
    fibroelastic tissue, connects epiglottic and arytenoid cartilages, upper free border is aryepiglottic fold at aditus or entrance to larynx, lower free border is vestibular ligament or false vocal cord
  12. triangular or cricothyroid membrane
    • fibroelastic tissue, connects cricoid, thyroid, and arytenoid cartilages, upper free border is vocal ligament or true vocal cord.
    • The triangular & vocal ligaments together form the conus elasticus (which acts as a sphincter or valve guarding the airway of the trachea).
  13. vocal ligament
    • the “skeleton” of the true vocal cords and attaches the arytenoid to the thyroid cartilage.
  14. functioning of vocal cords
    • Air rushing past the vocal cords, which are adducted and tense, will cause the cords to pulsate or vibrate, thus separating the stream of air into individual and discrete puffs of air (sounds) whose pitch (tone) is determined by the length of segments of the vocal cords which vibrate and by their rate of vibration.
    • By altering the tension on the cords and by changing their lengths (action of cricothyroid muscles), and by imposing different tensions on different parts of the cords, the quality and pitch of the sound is altered.
    • These changes are produced by the laryngeal muscles.
    • The sound generated by the larynx is altered by the lips, tongue, teeth and palate, and nasal cavities to produce speech.
    • The larynx alone is simply a sound-generating device.
  15. Muscles of Larynx
    • The intrinsic striated muscles are attached to the external surfaces of the skeletal framework of the larynx and are covered by the mucosal lining of the pharynx.
    • The muscles which act on the vocal cords can be divided into 4 functional groups.
    • 1. adductors-lateral cricoarytenoid
    • transverse arytenoid (part of the interarytenoid)
    • oblique arytenoids (part of the interarytenoid)
    • 2. abductor- posterior cricoarytenoid (the only abductor of the vocal cords)
    • 3. tensor-cricothyroid (may be seen in the anterior triangle)
    • 4. relaxors-thyroarytenoid & vocalis
    • Note: Do not worry about the aryepiglotticus and thyroepiglottis muscles. These muscles help to close off the laryngeal aditus or inlet.
  16. larynx adductors
    • interarytenoid muscle consisting of lateral cricoarytenoid and transverse arytenoid
  17. larynx abductor
    • posterior cricoarytenoid
  18. larynx tensor
    • cricothyroid
  19. larynx relaxor
    • thyroarytenoid & vocalis
  20. Laryngeal Regions
  21. vocalis
    is a relaxor of the vocal cords. It is considered by some to be the medial fibers of the thyroarytenoid.
  22. Larynx aditus
    entrance: bounded by the epiglottis, aryepiglottic folds, arytenoid cartilages, and the interarytenoid fold.
  23. Larynx vestibule
    lined with stratified squamous epithelium and extends from the aditus to the vestibular folds or false vocal cords.
  24. Larynx ventricle
    • lined with ciliated columnar respiratory epithelium and is located between the vestibular folds (false vocal cords) and vocal folds (true vocal cords).
    • The true vocal cords are covered by a stratified squamous epithelium.
  25. Larynx rima glottis and glottis
    • The rima glottis is a slit-like space between the true vocal cords.
    • The glottis is the area that includes both the true vocal cords and the space between them (the rima glottis).
  26. Larynx infraglottic cavity
    • lined with respiratory epithelium
    • located below the vocal folds and extends to the lower border of the cricoid cartilage.
  27. Larynx Innvervation
    • vagus (CN X) supplies sensory (VA) and parasympathetic innervation (VE-para/pre) to the mucosa and mucus glands of the larynx.
    • CN XI via X (branchial motor) fibers innervate all the muscles of the larynx.
    • All these fibers are brought to the larynx via two branches of the vagus – the superior laryngeal and recurrent laryngeal nerves.
  28. Superior laryngeal n (divides into 2 branches)
    • 1. external laryngeal n: motor supply to the cricothyroid (XI via X fibers - BM)
    • 2. internal laryngeal n: sensory (VA) and parasympathetic preganglionic (VE - para/pre) supply to the mucosa & mucus glands of the larynx from the glottis up to the aditus.
  29. external laryngeal n
    • motor supply to the cricothyroid (XI via X fibers - BM)
  30. internal laryngeal n
    sensory (VA) and parasympathetic preganglionic (VE - para/pre) supply to the mucosa & mucus glands of the larynx from the glottis up to the aditus.
  31. Recurrent laryngeal n.
    • motor supply (XI via X) to all the intrinsic laryngeal muscles except the cricothyroid.
    • It also supplies sensory (VA) and VE para/pre fibers to the mucosa & mucus glands of the larynx below the vocal cords or glottis (i.e., the infraglottic cavity).
    • Note: Remember that the VE-para/pre fibers synapse on VE-para/post cell bodies that are located in the submucosa of the target organ (or region).
    • It is the VE-para/post fibers that will directly innervate the mucus glands in those regions.
  32. superior laryngeal artery
    • branch of the superior thyroid a, accompanies the internal laryngeal nerve and enters the larynx by piercing the thyrohyoid membrane.
    • Note: both arteries and accompanying nerves cross the piriform recess of the pharynx deep to the mucosa to reach the larynx.
  33. inferior laryngeal artery
    • a branch of the inferior thyroid a (which is a br. of the thyrocervical trunk of the 1st part of the subclavian a.),
    • accompanies the recurrent laryngeal nerve and enters the larynx by slipping under the lower border of the inferior pharyngeal constrictor muscle.
    • Note: both arteries and accompanying nerves cross the piriform recess of the pharynx deep to the mucosa to reach the larynx.
  34. Sphinteric
    • actions to close off the upper of the respiratory system during:
    • 1. swallowing - to close off the aditus and vestibule
    • 2. coughing - a cough or sneeze requires a forceful expulsion of compressed air to clear the airways. The vocal folds are powerfully adducted while the respiratory muscles contract to increase intrathoracic pressure. There is a sudden release or abduction of the vocal folds which sends a stream of air rushing through the larynx.
    • 3. abdominal straining - to increase intraabdominal pressure during urination or defecation.
  35. Phonation
    • Tone or pitch is controlled by varying the length of the vibrating segments of the vocal cords.
    • The anterior ends of the cords vibrate for highest tones and progressively lower tones are produced as longer and longer anterior segments of the vocal cords vibrate.
    • The muscles that primarily affect the length of the vocal cords are the:
    • 1. cricothyroid - which lengthens and tenses the entire vocal cord
    • 2. vocalis - which controls the length of the vibrating segment of the vocal cord.
    • Note: There is also some elevation of the larynx as a whole for higher tones and lowering of the larynx for lower tones.
    • The larynx produces sound varying only in intensity and tone or pitch. Speech is produced by changes in the position of the soft palate and the tongue by use of the teeth and lips.
  36. Larynx Muscles Diagram
  37. Larynx Cartilages
  38. Larynx Regions
  39. Larynx Folds
  40. Vocal Cords
  41. Larynx Ligaments