L33 - Swallowing and speech Flashcards
3 stages of swallowing?
• Oral stage • Pharyngeal stage • Esophageal stage
What are the processes that occur in the oral stage of swallowing? (4)
1) Chewing, Mastication
2) Tongue movement: Load food bolus onto tongue + push bolus back to oropharynx
3) Posterior oral cavity (glossopalatal gate) is closed
Integrity of hard palate seal nasal cavity
Assign the processes in oral phase of swallowing with neural control? which nerves involved?
Masticator muscles = V3 (mandibular)
Tongue muscles(loading and pushing bolus) = CN XII (hypoglossal)
Sensation = V2 (maxillary) + V3 (mandibular) + CN IX (glossopharyngeal, at soft palate, posteriro 1/3 tongue)
processes that occur in the oropharyngeal stage of swallowing? (5)
- Glossopalatal gate opens at posterior oral cavity
- Soft palate elevate to close nasopharynx and nasal aperture
- Larynx begins to elevate
- Tongue movement (anterior to posterior) propel bolus into pharyngeal cavity
- Activate mechanoreceptors to trigger swallowing reflex
Assign the processes in oropharyngeal phase of swallowing with neural control? which nerves involved?
- Soft palate elevation to close nasopharynx, nasal aperture = CN V3 (tensor veli palatini and open eustachian tube) + CN X exam
- Laryngeal elevation = CNV, CNVII, CNXII, Cervical plexus
- Tongue movement to propel food into pharyngeal cavity = CN XII
- Activate mechanoreceptors, sensation»_space; Pharyngeal plexus: CN IX, CN X»_space; brainstem»_space; swallowing reflex start
processes that occur in the pharyngeal stage of swallowing? (5)
Complex muscle contraction:
- Larynx fully elevated
- Upper esophageal sphincter (UES) opens
- Epiglottis folds over airway to close laryngeal aperture
- Vocal cords close
- Beginning of pharyngeal peristalsis
Assign the processes in pharyngeal phase of swallowing with neural control? which nerves involved?
- Closure of glottis (vocal folds) = CN X (recurrent laryngeal nerve)
- Opening of upper esophageal sphincter = CN X (pharyngeal plexus)
- Sensation = CN IX, CN X (superior laryngeal nerve)
- Laryngeal elevation = CNV, CNVII, CNXII and cervical plexus
processes that occur in the esophageal stage of swallowing? (4)
Lower esophageal sphincter relaxes; Upper esophageal sphincter close after bolus passes into esophagus completely
Esophageal peristalsis until bolus expelled into stomach
Airway re-open
Larynx down
List 4 mechanisms that prevent aspiration of food into lungs?
- Closure of glottis (true vocal cord) (= primary)
- Closure of false cords (= primary)
- Elevation of larynx + folding of epiglottis to cover laryngeal inlet (= secondary)
- Generation of positive subglottic pressure in trachea (vs negative pressure in esophagus)
What are some clinical symptoms of abnormal swallowing reflex? (5)
Dysphagia Cough Choking Globus (lump in throat) Aspiration pneumonia
What are some causes of abnormal swallowing reflex? (Think which part of the channel is affected)
Intra-luminal (e.g. tumor in esophagus)
Intra-mural (e.g. myopathies)
Extraluminal (e.g. goiter compresses on esophagus)
CNS pathologies (loss of control, coordination)
List 3 investigations for abnormal swallowing reflex?
Endoscopy (intra-luminal, intra-mural)
VFSS (videofluroscopic swallowing study): swallow something radio-opaque
Manometry/ esophageal motility study (measure whether UES and LES can relax)
Define phonation?
generation of sound by forcing air through the larynx and causing the vocal folds to vibrate
Define articulation?
Generation of sounds that involves moments of the mandible, lips, larynx, soft palate, tongue
List the 3 adductors of the larynx and their function?
lateral cricoarytenoid muscle (Major)
transverse and oblique arytenoid muscle
Adduct vocal ligaments»_space; close the glottis»_space; generate ‘subglottic pressure’
Describe the mechanism of phonation
Pressure above 3-5 H2O
> > forces vocal folds apart
> > subglottic pressure falls immediately
> > vocal folds close again
> > vibration of vocal folds
List 2 muscles that shorten the vocal cord?
Thyroarytenoid, vocalis muscle
What is the typical pitch of male and female voice?
Male: 120 Hz (low C)
Female: 230 Hz (middle C)
List the muscle that lengthens the vocal cord and its innervation?
cricothyroid = supplied by SUPERIOR laryngeal nerve (external division)
All the other larynx muscles are supplied by RECURRENT laryngeal nerve
What muscle works against the lateral cricoaryntenoid, transverse and oblique arytenoid muscles? (adductors)
Posterior cricoarytenoid (PCA) = intrinsic muscle, only abductor of vocal ligaments
Significance of the posterior cricoaryntenoid muscle?
the only abductor that opens the vocal folds for inspiration
Paralysis = die from suffocation
3 gross histological layers of the vocal cord?
Epithelium
Subepithelial tissue: 3 layered lamina propria
Vocalis, thyroarytenoid muscle (shorten vocal cords)
Type of epithelium at vocal cords?
Superiorly, inferiorly: pseudostratified columnar epithelium
At contact surface of medial cord: nonkeratinizing squamous epithelium
Distinguish 3 layers of lamina propria in the vocal cords?
- Superficial layer (Reinke’s space): Allows epithelium on top to vibrate freely: if damaged: hoarse voice
- Intermediate layer
- Deep layer
Intermediate + deep layers make up the vocal ligament
What determines the loudness of phonation?
– Depends on the force of expiration
– Lung function, respiratory muscles
What determines the pitch of voice? (3)
Depends on “dimensions” of vocal folds:
– Size of the larynx (larger in male = longer vocal cord= lower pitch)
– Tension and length of vocal folds: tense/ lengthened = high frequency
– Intrinsic laryngeal muscles: width of vocal fold opening (i.e. Posterior arytenoid muscle that opens vocal folds)
List some causes of hoarseness? (3)
- COPD (affects lung)
- Recurrent laryngeal nerve palsy = laryngeal muscle paralysis (surgical complication, neurological problem)
- Vocal folds pathologies (polyps, cancer) = impede normal vibration (Superficial lamina propria and epithelium cannot vibrate freely)
Investigations into voice hoarseness?
– Cross-sectional imaging (CT, MRI), endoscopy
Which structures are involved in articulation and give their innervation?
Mandible- masticator muscles = CN V (V3) Lips = CN VII Larynx = CN X Soft palate = CN X + CN V3 Tongue = CN XII
Mechanism of articulation?
Change in the shape of the upper aerodigestive tract
> > change the resonance chamber
> > produce different harmonics of the tone (e.g. nasal speech)
Poor articulation is commonly due to what pathology?
Pathologies in higher centre (e.g. cerebellum dysfunction) = poor coordination of muscles
Which area of the brain is affected if presented with Expressive aphasia or dysarthria?
(L) frontal cortex (Broca’s area)
Expressive aphasia = cannot convert thought into speech, can write or use sign language
Dysarthria = tongue cannot move properly for speech
Difference between expressive and receptive aphasia and the areas of brain involved?
Expressive aphasia = cannot convert thought into speech = Broca’s area
Receptive aphasia = cannot understand written or spoken language = Wernicke’s area
What are some causes of dysarthria? Investigations?
Tongue tie (abnormally thick oral frenulum)
oral pathologies (cancer affecting tongue muscles)
CNS pathologies (stroke, CNS tumour affecting tongue muscle innervation, sensation)
Endoscopy, CT brain
