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
State the function of internal laryngeal muscles
moves the indiv. components of the larynx –> plays a vital role in breathing & phonation
State which muscle is the most important & why
cricoarytenoideus dorsalis
- responsible for abducting the arytenoid cartilage to open the glottis
State where this muscle originates from
the dorsolateral surface of the cricoid cartilage
State where this muscle inserts into
the muscular process of the arytenoid cartilage
State where the cricoarytenoideus lateralis muscle originates from
the craniolateral surface of the cricoid cartilage
State where the cricoarytenoideus lateralis muscle inserts into
the muscular process of the arytenoid cartilage
State the function of the cricoarytenoideus lateralis muscle
to pivot the arytenoid cartilage inwards to close the glottis space
The thyroarytenoideus muscle gives rise to _____ & _____ muscles
ventricularis
- vocalis
State where the thyroarytenoideus muscle originates from
the internal midline of the thyroid cartilage
State where the thyroarytenoideus muscle inserts into
the arytenoid cartilage, primarily on the deep surface of the muscular process
State the function of the vocalis portion
draws the arytenoid cartilage downwards
–> relaxing the vocal cords
State the function of the ventricularis portion
constricts the glottis & dilates the laryngeal saccule
State where the arytenoideus transversus muscle originates
the muscular process of the arytenoid
State where the arytenoideus transversus muscle inserts into
the interarytenoid cartilage
State what occurs when the arytenoideus transversus muscle is contracted
epiglottis is drawn downwards
State where the cricoidthyroideus muscle is located
lies laterally b/n the thyroid lamina & the cricoid cartilage
State the function of the cricoidthyroideus muscle when contracted
pivots the cricoid cartilage on its thyroid articulation
–> tensing the vocal cords
Innervation to the larynx is provided mainly by _____ & _______ laryngeal nerves
- cranial
- caudal
Where do laryneal nerves originate from?
vagus nerve, CN X
State the function of the caudal laryngeal nerve
provide motor supply to all intrinsic/internal muscles in the larynx except for the cricothyroideus.
Explain the blood supply to the larynx
branches of the cranial & caudal thyroid arteries
Major salivary glands function through ________ ________
connective ducts
List the major & minor salivary glands
MAJOR: parotid mandibular sublingual zygomatic
MINOR: labial lingual buccal palatine
Describe the innervation of salivary glands (2)
- sympathetic: vasoconstriction occurs & the flow of saliva is decreased
- parapsympathetic: facial (CN VII) & glossopharyngeal (CN IX) nerves & some branches of the trigeminal nerve (CN V).
–> the flow of salivary fluid increases & vasodilation occurs
Which of the following is NOT a bone of the Hyoid Apparatus?
a. Keratohyoid
b. Epihyoid
c. Sesamohyoid
d. Thyrohyoid
e. Basihyoid
c. Sesamohyoid
Which of the hyoid cartilages below is paired?
a. Aritenoid
b. Thyroid
c. Cricoid
d. Epiglottis
a. Aritenoid
Choose the option that completes the sentence below:
“In cows, the ________ gland is located adjacent to the mandibular gland”.
a. Zygomatic
b. Sublingual
c. Parotid
d. Dorsal
c. Parotid
State the type of muscle contained in the tongue
striated muscle –> therefore, is mobile
The tongue is supported caudally by ______
hyoid bone
List the functions of the tongue (5)
- grooming
- lapping
- prehension & manipulation of food in the oral cavity
- deglutition reflex
- vocalisation
Describe the ‘lyssa’ structure in the tongue (3)
- firm, cartilaginous, almost bony structure
- lies along the median ventral surface under the tip of the tongue
- right below the frendulum
State the function of the ‘lyssa’
the lyssa, along w/ other muscles in the tongue changes the conformation of the tongue so animals are able to rotate the apex of the tongue backwards to capture water –> facilitates the process of drinking water
List the intrinsic muscles in the tongue (2)
- dorsal longitudinal
- ventral longitudinal
List the extrinsic muscles in the tongue (4)
- styloglossus
- genioglossus
- hyoglossus
- geniohyoideus
State the function of the styloglossus
State the function of the styloglossus
State the function of the genioglossus
protrudes & depresses the tongue
State the function of the hyoglossus
retracts & depresses the tongue
State the function of the geniohyoideus
draws the hyoid & therefore, the tongue forward
- lies below the tongue (not w/i it)
State how innervation in the tongue is divided (3)
- movement
- sensation (temp. & touch)
- sensation (taste)
Describe innervation in the tongue for movement
hypoglossal nerve (CN XII)
Describe innervation in the tongue for sensation (temp. & touch)
rostral 2/3 of the tongue
- lingual branch of the trigeminal (CN V) nerve
Describe innervation in the tongue for sensation (taste)
caudal 1/3 of the tongue
- glossopharyngeal (CN IX) nerve
Describe the vasculature of the tongue (4)
- lingual artery (main)
- branches of the external carotid artery
- branches of the facial artery
- branches of the ascending pharyngeal artery
Describe the 5 types of papillae on tongues
- conical
- mechanical
- absent in horses
- present in the caudal 1/3 of the tongue
- no taste buds
- thick epithelium - foliate
- gustatory
- 8-12 papillae in parallel folds, one either side of the tongue midline
- stratified squamous epithelium in caudal 1/3 of the tongue
- taste buds present
- absent in ruminants - vallate
- gustatory
- taste buds present
- lymphatics present - fungiform
- red dots on tongue surface
- consist of keratinised, stratified squamous epithelium & blood vessels
- involved in loss of heat via panting in dogs
- present in rostral 2/3 of tongue
- taste buds present - filiform
- mechanical
- most numerous
- point caudally
- no taste buds, glands, / lymphatics
- smallest
- consist of thick keratin on stratified squamous epithelium
- very prominent in cats
- present in rostral 2/3 of tongue
Define ‘teeth’
hard, calcified structures located in the jaws (& oral cavity) of many vertebrates
List the functions of teeth (4)
- mastication
- piercing
- hunting
- defense
State the function of ‘enamel’
- covers the head & the crown of the teeth
State what the inner part of the teeth are lined by (2)
- cement
- dentin
State what is inside the pulp cavity of teeth (3)
- blood vessels
- nerves
- lymphatics
The difference in teeth anatomy in mammals are due to patterns of ______ & _______.
- growth
- morphology
Describe Brachydonts (3)
- low-crowned teeth
- in humans, carnivores (e.g dogs, cats, pigs)
- tooth has acrown above the gingiva (a constricted neck at the gumline & the root embedded in the jaw bone)
Describe the structure of enamel (2)
- densely packed w/ mineral/crystals
- heavily mineralised w/ calcium salts
Describe the structure of cementum
- calcified connective tissue
Describe the structure of cementum
- calcified connective tissue
Describe the structure of dentin (2)
- a bone-like material
- makes up most of the tooth
Describe Hypsodonts
- high-crowned teeth
- continue to erupt throughout life
- e.g permanent teeth of horses
- e.g cheek teeth of ruminants
- tooth has a body, much of which is below the gum line & root, which is embedded in the alveolus of the jaw line
Describe ‘alveolus’
a socket in the jawbone where the tooth is attached to
List the 4 type of specialized teeth (4)
- incisors (I)
- canine teeth (C)
- premolars (P)
- molars (M)
State the function of ‘dental formulae’
used to indicate the no. of each type of tooth for a given species
Which extrinsic muscle of the tongue is responsible for retracting and elevating it?
a. Styloglossus
b. Genioglossus
c. Hyoglossus
d. Geniohyoideus
a. Styloglossus
Which papillae are more prominent in cats?
a. Conical
b. Vallate
c. Fungiform
d. Filiform
d. Filiform
True or False?
“The frenulum is a firm cartilaginous, almost bony structure lying along the median ventral surface under the tip of the tongue.”
False
The lyssa is a firm cartilaginous, almost bony structure lying along the median ventral surface under the tip of the tongue.
