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1.21.3.10 - The Larynx and Hyoid Apparatus - Coggle Diagram
1.21.3.10 - The Larynx and Hyoid Apparatus
what is the larynx?
cartilaginous tube
valve
sound maker
pressure control
location
ventral to the laryngoparhynx
caudal to tongue
syspended by hyoid apparatus
palpable caudal to jaw
horses, ruminants, birds
between rami of mandible
carnivore, pig, human
neck
spaces around the larynx
trachea
oespohagus
entrance to the oesophagus is called the laryngopharynx
common pharynx
oropharynx is below the soft palate
functions
connection of nasal part of pharynx and trachea
breathing/respiration
some animals are obligate nose breathers e.g. horses
mouth breathing is hard if not impossible and indicative of something wring
ruminants mouth break if they do a lot of galloping
protection of lower airways
swallowing
straining
couhging
formation of voice (phonation)
birds use a syrinx
hard palate has ridges so where that stops is where the hard plate starts
hyoid apparatus
suspended by the hyoid bones which articulate with the base of the skull
linked by synocvial joints of cartilaignous joints
difference between cat/dog & horse apparatus
bovidae
similar to horse
epihyoid and stylohyoid are equal size
lingual process shorter
porcine
usual pattern
short epihyoid
like a swing, the larynx can only go forwards or backwards
stylohyoid and epihyoid - no joint in the middle so the hyoid apparatus cannot collapse up on itself
horse larynx is less able to move forwards and backwards
clothesline
obligate nose breathers
larynx
hyaline and elastic cartilage
skeleton of the larynx
collagenous and elastic ligaments
striated mucles
vessels
mucous membranes
nerves
rigid tubular box made up of mostly rigid cartilage but some elastic cartilage
larynx cavities
entrance to the larynx = vestibule
glottis
space created through which something will go
ingraglottic cavity
hourglass shape
long air tube
species dependent has lateral ventricles on either side of the glottis
larynx opens and closes due to change in shape of the larynx
mucosa
epithelium + lamina propria
stratified squamous at the entrance (epiglottis)
pseudostratified ciliated
cilia propel mucous up from the larynx to be coughed up or to be swallowed into the stomach
laryngeal cartilages
hyaline cartilages
cricoid - signet ring shaped
thyroid - u shaped
paired arytenoids - triangular
pale plue down a microscope
cartilage with elastic fibres
elastic cartilage
epiglottis - leaf shaped
palpable landmarks
thyroid cartilage cranio-ventral in the midline
cricoid cartilage caudoventral
first cartilage of the trachea
connections of cartilages
connection between themselves
connections with trachea and hyoid bones
joints
synovial
cartilagenous
collagenous and elastic ligaments
striated musculature
named by origin and insertion
laryngeal muscles
phonation and swallowing
inspiration
striated muscle
intrinsic muscles between cartilages
respiration and phonation
extrinsic muscles connect the larynx to hyoid bones pharynx and sternum
swallowing
intrinsic muscles
Cricoarytenoideus dorsalis
supplied by laryngeal recurrent nerves
extrinsic muscles
Cricoarytenoideus lateralis
closes the larynx
powerful in cats
local anaesthestic before passing a tube
learn the cricoarytenoideus dorsalis
laryngeal nerves
innervation
two nerves on each side
cranial laryneal nerve (X)
sensory innervation of laryngeal membrane
motor innervation of cricothyroideus
recurrent (caudal) laryngeal nerve (XI)
innervates all laryngeal muscles except cricoityroideus
acsends the neck after vagus
recurrent laryngeal nerves
left and right recurrent laryngeal nerves
run along the trachea
innervate intrinsic laryngeal muscle
swallowing and breathing
closure during walloing
sudden opening permits coughing
closure during importan straining
micturition
parturition
defecation
lifting/pushing
important for eructation and rumination in ruminants
larynx is drawn rostrally and moved dorsally
main seal of closure is the glottis
clinical links
laryngoscpy
whistling noises during inspiration
hemiplegia
collapsed vocal folds
birds
no vocal folds, no creation of sounds
glottis can be closed to precent food entering larynx/trachea
consists of cricoid and arytenoid cartilages
syrinx
sound production
vibrating membrane
ligaments
vocal fold
vestibular fold