10 - Larynx Flashcards
What are the functions of the larynx?
Protective sphincter for lower resp tract against food
Speech
Breathing - allows air exchange from lungs
What is the larynx?
Below hyoid bone, begins at laryngeal inlet extends to lower cricoid cartilage where it becomes the trachea
What is the route inspired air takes?
Oral cavity/ Nasopharynx
Oropharynx
Larynx
Trachea
What is the route food takes?
Oral cavity
Oropharynx
Laryngopharynx
Oesophagus
Describe the framework of the larynx
Thyroid membrane connected to hyoid bone (sup) and thyroid cartilage (inf)
Thyroid cartilage connected to cricoid cartilage by synovial joint and cricothyroid membrane
Thyroid cartilage connects to epiglottis by ligaments
Cricoid cartilage has arytenoid cartilages sitting on top
When is the cricothyroid membrane used to reach airway?
Patient can’t be intubated or ventilated - swelling to vocal cords, emergency
What is the function of the quadrangular membrane?
Joins epiglottis ti aryetenoid cartilage
What are aryepiglottic folds?
Quadrangular membrane covered by mucosa, form beginning of larynx
Sides of folds form piriform fossa
What is the vestibular ligament?
Free border of quadrangular membrane, false vocal cord
What is the vocal ligament?
Upper free borders of cricothyroid ligament, forming vocal cord
Where is the larynx in relation to the laryngopharynx?
Anterior
What are the divisions of the larynx?
Supraglottis - larynx above vocal cords
Glottis - true vocal cords and gap between them
Infraglottis - Below vocal cords to lower cricoid cartilage
What type of epithelium lines the larynx?
Pseudostratified ciliated columnra epithelium
What type of epithelium lines the vocal cords?
Stratified squamous epithelium - better deals with abrasive force of constant friction
What is the function of the laryngeal muscles?
Alter size and shape of inlet
Alter tension in vocal cords
Which combined, closes larynx during swallowing, protecting respiratory tract
Opens larynx, allowing movement of air
Control movements of vocal cords in phonation and in cough reflex
What muscle abducts (opens) vocal cords?
Posterior cricoarytenoid
What determines the position and thus size of aperture of vocal cords?
Position of arytenoids on cricoid cartilage
Describe the innervation of the muscles of the larynx
All by recurrent laryngeal nerve of vagus X
Except cricothyroid - superior laryngeal X
Describe the movement of the vocal cords during breathing?
Vocal cords abduct
Glottis wide open
Describe the movement of the vocal cords during phonation
Vocal cords adduct
Expired air forced through closely adducted vocal cords to vibrate a column of air
Describe the movement of the vocal cords during a cough
Vocal cords powerfully adducted
Intrathoracic pressure builds
Vocal cords suddenly abducted
How is vocal pitch altered?
Bilateral contraction of cricothyroid muscle increases length and tension of vocal cords, making them taut, high pitch sounds
Low pitched, vocal cords relaxed
What is the effect of superior laryngeal nerve damage?
Hoarse voice, especially when attempting high pitch sounds
How is the airway protected during swallowing?
Contraction of aryepiglottic muscles narrows laryngeal inlet and pulls down epiglottis
Elevation of larynx by pharyngeal and suprahyoid muscles
Vocal cords close
