The larynx structure and function
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The larynx structure and function
Larynx Anatomy Function
Vet Med - Module 9
Which structure does the larynx lead to?
What is attached to and alters the position of the larynx?
The hyoid apparatus
Describe the position of the larynx
The larynx is attached by the hyoid apparatus to the cranium between the rami of the mandibles. It is situated ventrally in the common pharynx at the base of the tongue
In which species does the position of the larynx differ from most others?
The horse - the larynx is positioned more dorsally
What is positioned dorsal/ventral to the larynx?
Dorsal - oesophagus, base of skull, atlas
Ventral - ventral muscles of the neck, skin
What are the three functions of the larynx?
It guards the entrance to the trachea during swallowing
Regulates the amount of air entering the lower respiratory passageways by adducting or abducting the glottis
Vocalisation by varying the tension on the vocal chords
List the bones of the hyoid apparatus
Which of the hyoid apparatus bones is not paired?
What are the cartilages of the larynx? Which is paired?
Arytenoid - paired
What shape are the cartilaginous rings in the trachea?
What shape is the epiglottis in the dog?
What does the epiglottis form the rostral edge of?
The laryngeal aditus
Which cartilage in the larynx does the epiglottis articulate with?
What direction does the epiglottis tip in during swallowing?
What type of cartilage is the epiglottis composed of?
What shape is the thyroid cartilage?
U shaped - it is made up of two lateral plates that fuse ventrally
Which structures does the thyroid cartilage articulate with?
Thyrohyoid bone and arch of the cricoid cartilage
What type of cartilage is the thyroid cartilage composed of?
What shape is the cricoid cartilage?
A signet ring (wide dorsally, narrow ventrally)
What structures does the cricoid cartilage articulate with?
The arytenoids and thyroid cartilages
What ligament links the cricoid cartilage to the trachea?
The cricotracheal ligament
What type of cartilage is the cricoid cartilage composed of?
What shape are the arytenoid cartilages?
Irregular, but best described as pyramidal
Where are the arytenoid cartilages located in the larynx?
Dorsal and medial to the thyroid cartilage
What structure do the arytenoid cartilages articulate with?
The cricoid cartilage
What are the three processes present on the arytenoid cartilages? And what are their functions?
Vocal process - supports vocal fold
Corniculate process - supports aryepiglottic fold
Cuneiform process - present in horses, dogs and pigs
What is the laryngeal aditus? What structures make up the laryngeal aditus?
It is the entrance to the larynx
It is made up of the epiglottis, corniculate processes of arytenoid cartilages, aryepiglottic fold
What other mucosal folds are present in the larynx?
Vestibular folds in some species
What is the function of the glottis?
It controls the amount of air entering the trachea
What are the boundaries of the glottis?
The vocal process of the arytenoid cartilages, vocal folds, thyroid cartilage
What happens to the glottis during swallowing?
It is closed during swallowing
What shape is the epiglottis in ruminants?
What larynx structures do ruminants not have?
Vestibular folds, lateral ventricles, cuneiform processes
What shape is the epiglottis in pigs?
Large with a rounded apex
What is different about the arytenoid cartilages in pigs?
They have a bifid corniculate process
What shape is the epiglottis in horses?
It is pointed
Do horses have cuneiform processes?
Why is surgery on the larynx easily accessible in horses?
As they have a large thyroid notch