Lecture 10 - Pharynx and Larynx Flashcards
functions of pharynx
- shared passageway for both air and food
- provides a resonating chamber for speech and sounds
- houses the tonsils, which serve immunological functions
Divisions of pharynx (3)
- nasopharynx (superior portion)
- oropharynx (middle portion)
- laryngopharynx (inferior portion)
Relating anatomy of this lecture
- oral cavity
- tongue
- pharynx
- hyoid bone
- vertebral bodies
- larynx
- esophagus
Nasopharynx: borders
- superior: choanae
- posterior: vertibral bodies
- anterior/inferior: soft palate and oropharynx
Nasopharynx: function
respiratory function
Nasopharynx: key features
- soft palate
- openings to eustachian tube
- adenoid (pharyngeal tonsil)
Soft palate
- forms the posterior roof of mouth
- arch shaped muscular partition between the nasopharynx and oropharynx
Soft palate: swallowing
- contracts to close the nasopharynx when swallowing
- tongue blocks oral cavity
- soft palate blocks nasophasrynx
Eustachian tube
- narrow passage between the nasopharynx and middle ear
- allows air echange to equalize pressure between these areas
adenoid
- “pharyngeal tonsil”
- patch of lymphoid tissue on the superior posterior wall
- typically atrophies and shrinks significantly by adulthood
oropharynx: borders
- superior: nasopharynx
- inferior: laryngopharynx
- posterior: vertebral bodies
- anterior: fauces (aka throat)/oral cavity
oropharynx: functions
- respiratory
- digestive
oropharynx: key features
- palatine tonsils
- lingual tonsils
oropharyngeal tonsils
- patches of lymphoid tissue
laryngopharynx: borders
- superior: oropharynx
- posterior: vertebral bodie
- inferior: larynx and esophagus
laryngopharynx: functions
- respiratory
- digestive
laryngopharynx: key features
- laryngeal inlet
- piriform fossae (recesses)
laryngeal inlet
- entrance to the larynx
piriform fossae (recess)
- groove on either side of the laryngeal inlet
pharynx epithelium
- pseudostratified ciliated columnar epithelium (respiratory epithelium)
- nonkeratinized stratified aquamous epithelium
Pharyngeal muscles: outer circular layer
- superior constrictor
- middle constrictor
- inferior constrictor
superior constrictor: muscle #
S1-S4
superior constrictor: location
surrounds the oropharynx
superior constrictor: function
constricts the upper portion of the pharynx to faciliate swallowing
middle constrictor: muscle #
M1-M2
middle constrictor: location
surrounds the laryngopharynx
middle constrictor: function
constricts the middle portion of the pharynx to faciliate swallowing
inferior constrictor: muscle #
I1-I2
inferior constrictor: location
surrounds the laryngopharynx
inferior constrictor: function
constricts the lower portion of the pharynx to facilitate swallowing
- forms the upper esophageal sphincter
muscle attachments
- occipital bone (superior constrictor)
- pharyngeal raphe (groove or ridge) (superior, middle and inferior conctrictors)
Innervation of constrictor muscles
- motor innervation: vagus nerve (CN X)
- sensory innervation: glossopharyngeal nerve (CN IX)
Larynx
- aka voice box
- short passageway that connects the laryngopharynx with the trachea
- anterior to C4-C7
Larynx: function
- valve to close the trachea
- voice production (via vocal cords)
Larynx: cartilage structures
- epiglottis
- thryoid cartilage
- arytenoid cartilage (occur in pairs)
- cricoid cartilage
thryoid cartilage
- largest cartilage of the larynx
- form upper and anterior walls
- two fused plates of hyaline cartilage
- laryngeal prominence (adam’s apple)
thryoid cartilage: function
- protect and support the vocal cords
epiglottis
- leaf shaped piece of elastic cartilage
- covered wth epihelium
- “stalk” is attached to thyroid cartilage
- “leaf” is unattached
epiglottis; function
closes off larync during swallowing
Epiglottis: swallowing
moves down and forms a lid over the opening of the larynx
Cricoid cartilage
- ring of hyaline cartilage
- forms inferior wall of larynx
- landmarc for making an emergenxy airway!
Cricoid cartilage: function
maintains airway opening
Arytenoid cartilage
- triangular pieces of mostly hyaline cartilage
- sit on the cricoid cartilage
Arytenoid cartilage: function
influence movement (tension and relaxation) of vocal folds
Laryngeal ligaments
support the cartilaginous skeleton of the larynx
Laryngeal ligaments: divisions
- extrinsic
- intrinsic
Laryngeal ligaments: extrinsic
- attach larynx to external structures
- thyroid memebrane
- medial thyrohyoid lyragments
- lateral thyrohyoid ligaments
- criotracheal ligament
- thyroid memebrane
Laryngeal ligaments: intrinsic
- attack cartilages of the larynx
- cricothyroid ligament
Vocal cords
- the mucous membrane of the larynx forms two pairs of folds:
- superior
- inferior
What are the two types of vocal cords?
- true
- false
True vocal cords
- inferior: vocal folds
- principle structure of voice production
False vocal cords
- superior: ventricular folds
- protect the vocal folds
Cavities of the larynx (5)
- vestibule
- glottis
- rima glottidis
- infraglottic cavity (space)
- trachea
Vestibule cavity
from inlet to vestibular folds (false cords)
infraglottic cavity (space)
below vocal folds
glottis cavity
from vestibular folds to vocal folds (true cords)
rima glottidis cavity
gap between vocal folds
Actions of vocal cords during: respiration
- abduct/open
- allows the passage of air
Actions of vocal cords during: swallowing
- adduct/close
- to prevent food/liquid from entering
What do the intrinsic laryngeal muscles attach to?
the cartilage and vocal folds
Vocal resonance
- larynx and pharync are resonating chambers for speech
- reverberation of sound waves from the vibrating vocal folds
Actions of vocal cords during: phonation (the production of speech sounds)
- adduct and alter tension of vocal cords
Laryngeal muscles: overview
- intrinsic laryngeal muscles act on individual components of the larynx
Laryngeal muscles: functions/mechanisms
- control the shape of the rima glottidis
- control length and tension of the vocal folds
Cricothyroid: functions
- stretches and tenses the vocal ligament
- known as the “singe’s muscle” as it alters tone of voice
Thyroarytenoid: functions
- relax the vocal ligament
Laryngeal muscles: muscles
- cricothyroid
- thyroarytenoid
- posterior & lateral crioarytenoid
- transverse & oblique arytenoid
posterior & lateral crioarytenoid: functions
- Posterior: sole abductor of the vocal folds
- widens the rima glottidis
_ Lateral: major adductor of the vocal folds - narrows the rima glottidis
- widens the rima glottidis
Transverse & oblique arytenoid: functions
- adduct the arytenoid cartilage
- narrows the rima glottidis to modulate tone and volume of speech
Innervation of larynx - 2 nerves
- superior laryngeal nerve
- recurrent laryngeal nerve
Superior laryngeal nerve pathways
- internal laryngeal nerve -> sensory -> above vocal cords
- external laryngeal nerve -> motor -> cricothyroid
Recurrent laryngeal nerve pathways
- sensory -> below vocal cords
- motor -> all except cricothyroid
