anatomy of mouth and throat Flashcards
what are the functions of the larynx?
respiratory- Facilitate passage of air between the atmosphere and lungs
protective- Reduce the potential from aspiration of items into the airway
phonation- Generate vibrations in air to aid communication
what happens to the vocal fold during forced inspiration?
they abduct to allow passage of air
how is the protective function of the larynx achieved?
glottic clousre and cough reflex
how does larynx produce a sound (phonation)?
- Controlled expiration helps build pressure
- Once subglottal pressure threshold is reached then air crosses vocal cords causing vibration
- Length/tension of vocal cords dictates pitch of sound produced by vibration of the cords
- Degree of opening and the shape of the rima glottidis also important
what muscles tense the vocal ligament?
cricothyroid muscles
increases pitch
what muscles relax the vocal ligament?
thyroarytenoid muscles
decrease pitch
what muscles open the rima glottidis in forced respiration by contracting the vocal folds?
posterior crico-arytenoids
what muscles contract the rima glottidis into a thin slit for phonation?
arytenoids (assist lateral crico-arytenoids)
what happens when the lateral crico-arytenoids contract to produce a whisper?
vocal folds fully closed with small posterior opening to allow passage of air
what nerve supplies all intrinsic muscles of the larynx except the cricothyroid?
inferior laryngeal nerve
what nerve supplies the cricothyroid?
an external branch of the superior laryngeal nerve
where do supra-glottic tumours drain into?
superior deep cervical nodes
where do sub-glottic tumours spread to?
paratracheal nodes
present with voice/airway obstruction
how is sound articulation done?
- Soft palate tenses (CN V3) and elevates (CN X) to close off entrance into nasopharynx
- Directs stream of air through oral cavity
- Sound interrupted by the tongue (CN XII) and the teeth/lips (CN VII) to produce most vowels and consonants in English language
what are the 3 phases of swallowing?
oral phase (voluntary)
pharyngeal phase (involuntary)
oesophageal phase (involuntary
what happens in the oral phase of swallowing?
mastication (done by CN V3)
bolus manipulation (done by CN X and XII)
labial seal (done by CN VII)
what happens in the pharyngeal phase of swallowing?
hyolaryngeal elevation
sequential constrictor contraction
what happens in the oesophageal phase of swallowing?
relaxation of the upper oesophageal sphincter
what muscle creates a labial seal?
orbicularis oris
what muscle tightens the cheek?
buccinator
what happens in the pharyngeal phase of swallowing?
- Elevation of soft palate
Seals off nasopharynx from oropharynx - Posterior pressure from tongue
Seals off laryngeal aditus with help from epiglottis - Hyolaryngeal elevation
Protects airway
Opens upper oesophageal sphincter - Pharyngeal constrictor contraction
what muscles move the hyoid bone superiorly and anteriorly?
suprahopid and longitudinal pharyngeal muscles
what muscle causes relaxation of the upper oesophageal sphincter?
cricopharyngeus
how long does the oesophageal phase of swallowing last?
8-20 seconds
