The larynx and hyoid apparatus Flashcards
What are the functions of the larynx
- Voice Box
- connection of nasopharynx and trachea
- breathing
- Protection of lower airway
- swallowing
Describe the location of the larynx
Suspended by hyoid bones
Ventral to laryngopharynx
Caudal to tongue
What is the hyoid apparatus
Bones which hold larynx in place
Name the bones of the hyoid apparatus
Tympanohyoid Stylohyoid Thyrohyoid Basihyoid Ceratohyoid Epihyoid
What is different about the stylohyoid bone in a horse
A lot longer in the horse
Less flexible- keeps it in place
Name the different cartilages of the larynx
Hyaline: - Thyroid= U-shaped - Cricoid = signet ring - Paired arytenoids= triangular Elastic: - Epiglottis= leaf shaped
What type of mucosa line the larynx
- Strtified squamous at the entrance (epiglottis)
- Pseudostratified ciliated in other areas
What 3 types of structures connect the larynx cartilages to each other and to the trachea and hyoid bones
- Joints (cartilaginous or synovial)
- Collagenous and elastic ligaments
- Straited musculature
What are the 2 important synovial joints in the larynx
- Cricoarytenoid joint
- Cricothyroid joint
What does the Cricoarytenoid joint of the larynx allow
Allows rotation about both sagittal and transverse axis as well as sliding movements that bring the 2 arytenoid cartilages together or carry them farther apart
What does the Cricothyroid joint of the larynx allow
allows rotation about the transverse axis
What are the 2 ligaments in the larynx that move when the arytenoids move
- Vestibular ligament / fold
- Vocal ligament / fold
Where are the intrinsic muscles of the larynx located and what are they involved in
- Located between the laryngeal cartilages
- Involved in respiration and phonation
Where are the extrinsic muscles of the larynx located and what are they involved in
Connect the larynx to hyoid bones, pharynx and sternum
Involved in swallowing
What is the only muscle that widens the glottis- what innervates it
Cricoarytenoideus dorsalis- innervated by the recurrent laryngeal nerve
What are the 2 most important muscles that narrow/close the glottis
- Cricothyroideus
- Cricoarytenoideus lateralis
What does the cranial laryngeal nerve innervate in the larynx
- Sensory innervation of the laryngeal mucous membrane
- Motor innervation of the cricothyroideus
What does the recurrent laryngeal nerve innervate in the larynx
Innervation of all laryngeal muscles except the cricothyroideus muscle
How is the laryngeal entrance protected upon swallowing
- Larynx is drawn rostrally and moved dorsally
- Epiglottis tilts backwards and partially covers the laryngeal entrance
- Arytenoid cartilages approach each other
- Main seal is the closure of the glottis
What are 4 situations in which the glottis is closed
- During swallowing
- To allow pressure to build up before coughing
- During straining
- Closure is important during eructation and rumination in ruminants
What is idiopathic laryngeal hemiplegia more commonly known as
Roaring
Flaccid arytenoid cartilage is sucked into the laryngeal lumen
What structure is responsible for sound production in birds
Syrinx
