Lecture 6 - Upper Airways Flashcards
What is the nasopharynx?
Region of pharynx dorsal to the soft palate
Auditory tubes open into nasopharynx
How can an animal breathe whilst chewing?
- presence of palate allows breathing whilst chewing without aspiration of food
What is the normal position of the soft palate during
Free edge of sp rostral to epiglottis
Soft palate v long in horse, hang beneath epiglottis = horse unable to breathe through mouth
Soft palate rest over epiglottis in bracheocephlic dogs
Soft palate raised during deglutition = stop food entering nasopharynx
What is the function of auditory tubes and where do they lead from?
Equitation of pressure b/w middle ear cavity and external environment
Lead from middle ear cavity to open into lateral wall of nasopharynx
–> entrance opens during swallowing
what are guttural pouches, what species are they found in and where are the anatomical positions of the guttural pouches?
Only in horses
Air filled diverticula of auditory tubes
Paired structure (2) meet in the mid line ventrally and separated by rectus capitus
1 = medial to mandible between skull and atlas dorsally
2 = b/w pharynx and proximal oesophagus ventrally
What facial nerves, artery and lymph nodes are associated with the guttural pouches
Facial - CNVII Glossopharyngeal - CNIX Vagal - CNX Accessory - CNIX Hypoglossal - CNXII And sympathetic trunk Internal carotid artery Medial retropharyngeal lymph nodes
What is the function of the guttural pouches
Function unknown
Possibly: buffering pressure changes around middle ear
Cooling of blood to brain
Where to the guttural pouches drain?
Drain via auditory tubes into nasopharynx
What is the surgical approach to get to a guttural pouch?
Through viborgs triangle
Causal border of mandible
Sternocephslicus tendon
Linguofacial vein
Describe the wall and suspension of the larynx
Wall formed by laryngeal cartilage and muscles
Lined by mucous membranes
Suspended from skull by hyoid apparatus
What is the function of the larynx?
Connection between pharynx and trachea
Protection of the resp tract - closure during swallowing, sensory innervation (coughing reflex)
Vocalisation - vocal and vestibular folds
X2 components 1.phonation, 2.articulation
What are the unpaired laryngeal cartilages?
Epiglottis
Thyroid
Cricoid
What is the paired laryngeal cartilage?
Arytenoid
what are the two major processes on the arytenoid cartilage?
vocal process - vocal folds
muscular process - cricoarytenoideus dorsals and cricoarytenoideus lateralis
what is the function of movement of the arytenoid cartilages
responsible for closure of larynx
what cartilage is the arytenoid cartilage composed of
part hyaline
part elastic
describe the anatomical location of the arytenoid cartilage
medial to thyroid cartilages dorsally
caudal aspect articulates with rostral margin of cricoid
describe the anatomical location of the cricoid cartilage
enlarged dorsally to form roof of larynx
forms a ring
caudal and partly medial to thyroid cartilage
what cartilage is the cricoid cartilage composed of?
hyaline cartialge
what is the epiglottis cartilage composed of, where is it positioned anatomically?
composed of elastic cartilage
most rostral
what is the thyroid cartilage composed of and what boarder of the larynx does it form?
hyaline cartilage
form floor of the larynx
what are the 5 laryngeal cavities
laryngeal vestibule glottis vocal fold vestibular fold laryngeal ventricle
what is the laryngeal vestibule?
open rostral part of larynx
where is the glottis?
where the lumen narrows at the caudal end of the laryngeal vestibule.
what muscle is the vocal folds composed of?
m. vocalis and mucosal covering
what does the position of the vocal folds control?
the diameter of the glottis
how does phonation occur?
air passing over vocal folds
where is the vestibular fold located?
parallel to vocal folds - more rostral
what is the larygenal ventricle?
pocket of mouse between vestibular and vocal folds (particularly deep in horses)
what are the extrinsic muscles controlling the larynx?
pharyngeal constrictors - forming walls and roof of pharynx
muscles that move the larynx:
- throhyoideus
- sternothyroideus - draws larynx caudally
- hyoepiglotticus - draw ventrally
what are the intrinsic muscles that move the cartilages relative to each other?
cricothyroideus - moves cricoid cartilage dorsally,tensing vocal folds
cricoarytenoideus dorsalis - abduct vocal folds
thyroarytenoideus - composed of m. vocals, m.ventricularis
arytenoideus transversus
how is the larynx innervated?
vagus nerve CNX - provides sensory intro to larynx and motor innervation to all INTRINSIC MUSCLES OF larynx
what does the cranial laryngeal muscle innervate?
motor to cricothyroideus
sensory to mucosa cranial to the vocal folds
what does the caudal laryngeal nerve innervate?
motor to all intrinsic muscles except cricothyroideus
sensory to mucosa caudal to the vocal folds
damage to caudal laryngeal nerve = v serious
describe the larynx in birds
- not used for vocalisation
- occupies laryngeal mound on floor of pharynx
- no epiglottis only cricoid and arytenoid cartilages
- glottis formed by arytenoids, no vocal folds.
glottis closed by reflex action during swallowing
