Oral Cavity, Larynx, Pharynx and deglutition Flashcards
Define ‘prehension’
the act of getting food into the mouth.
Domestic animals do this by using their lips, teeth, tongue & by head & jaw movements
Define ‘mastication’
the mechanical breakdown of food & allows mixing w/ saliva
Define ‘deglutition (swallowing)’
the act of swallowing:
- initial phase = voluntary
- remaining phases = involuntary
State which muscle is used to retract the angle of the mouth
zygomaticus
State which muscle is used to elevate the upper lip & draw it to one side
levator labii superioris
State which muscle is used to keep the food b/n the upper & lower molar teeth during mastication
buccinator
State which muscle is used to close the lips & assist in gathering the food, in drinking, & in mastication
orbicularis oris
State the function of the zygomaticus
retract the angle of the mouth
State the function of the levator labii superioris
elevate the supper lip & draw it to one side
State the function of the buccinator
keep the food b/n the upper & lower molar teeth during mastication
State the function of the orbicularis oris
close the lips & assist in gathering the food, in drinking, & in mastication
State which nerve these muscles are innervated by
CN VII (facial nerve)
State what is the ‘jaw opening’ muscle
Digastricus muscle
State the location of origin of this ‘jaw opening’ muscle
paracondylar process of the occipital bone
State the location of insertion of this ‘jaw opening’ muscle
angle of the mandible
State the divisions of this ‘jaw opening’ muscle (2)
- caudal half - from the second visceral arch
- cranial half - from the first visceral arch
State which nerves each of these divisions are innervated by (2)
caudal half - the facial nerve, CN VII
- cranial half - the trigeminal nerve, CN III
State which nerve innervates all ‘jaw closing’ muscles
mandibular branch of the trigeminal nerve, CN V
State which ‘jaw closing’ muscle is used to close & protrude the jaw
masseter muscle
State which ‘jaw closing’ muscle is used to protrude the jaw (one-sided contraction)
lateral pterygoid muscle
State which ‘jaw closing’ muscle is used to cause one-sided contraction to close the jaw
medial pterygoid muscle
State which ‘jaw closing’ muscle is used to pull the mandible dorsally & also pull the mandible rostrally (overbite) & caudally (underbite)
temporalis / temporal muscle
State the function of the masseter muscle
close & protrude the jaw
State the function of the lateral pterygoid muscle
protrude the jaw (one-sided contraction)
State the function of the medial pterygoid muscle
cause one-sided contraction to close the jaw
State the function of the temporalis / temporal muscle (3)
- pull the mandible dorsally
- pull the mandible rostrally (overbite)
- pull the mandible caudally (underbite)
State the range of the oral cavity (2)
from the lips
- to the entrance into the pharynx
State the structures of the oral cavity (3)
- tongue
- teeth
- salivary glands
State the function of the guttoral pouch in horses
a paired ventral divertricule of an air field canal that connects the throat to the middle ear
Explain why brachicephalic dogs find it difficult to breathe
- have an elongated & thickened soft palate –> could cause pharyngeal & nasopharyngeal obstructions
- have a hypoplastic larynx (everted laryngeal saccules) that will collapse the laryngeal cartilage –> blocks flow of air
Which muscle closes and protrudes the jaw?
a. Digastricus
b. Masseter
c. Pterygoid
d. Temporalis
b. Masseter
The epiglottis is part of the:
a. Hard palate
b. Nasopharynx
c. Oropharynx
d. Larynx
d. Larynx
Select the best option to complete the statement below:
“Air, food and liquid all pass through this common passage: the oropharynx.
Then, food and liquid pass backward into the __________ on their way to the __________,
while air passes forward through the _________ and into the __________, on its way to the lungs”.
a. Pharynx, oesophagus, nasopharynx, larynx.
b. Oesophagus, stomach, pharynx, larynx.
c. Oesophagus, stomach, larynx, trachea.
d. Pharynx, oesophagus, larynx, trachea.
c. Oesophagus, stomach, larynx, trachea.
State where the hyoid apparatus is located (3)
- in the larynx
- after the pharynx
- b/f the trachea
State the function of the hyoid apparatus (2)
- holds the larynx in place
- supports the pharynx & tongue from the skull
Name the 5 diff. bones which make up the hyoid apparatus
- basihyoid –> unpaired bone
- stylohyoid –> paired bone, articulates w/ base of skull at the petrus temporal
- epihyoid –> paired bone
- keratohyoid –> paired bone
- thyrohyoid –> paired bone, articulates w/ the thyroid cartilage of the larynx
State how many cartilages are located w/i the larynx
9
Name the diff. unpaired & paired cartilages
unpaired:
- epiglottis
- thyroid
- cricoid
paired (situated bilaterally in the larynx):
- arytenoid
- corniculate
- cuneiform
State the function of cartilages in the larynx
provide rigidity & stability
State the function of external laryngeal muscles
elevates/depresses the larynx during swallowing