Head Associated Digestive Structures Flashcards
describe the 3 parts of the tongue
25% root
50% body
25% apex
what is the function of the lingual frenulum and where is it found?
it is the flap under the tongue; keeps the tongue from stretching too far
describe the sublingual caruncles
two papilla on either side of the lingual frenulum that receive products from the mandibular duct of the mandibular salivary gland and the monostomatic sublingual duct
list and describe the 4 major (2 encapsulated and 2 unencapsulated) salivary glands of the dog
Encapsulated:
1. mandibular gland (ice cream scoop) and associated with the monostomatic portion of the sublingual gland
2. sublingual gland: monostomatic portion (ice cream cone) is one gland with one mouth and one duct
polystomatic portion: minor (unencapsulated) salivary glands) have multiple mouths where each tiny gland ducts directly into the oral cavity
Unencapsulated
3. parotid gland: has a parotid duct that drains near the upper 4th premolar (carnassial tooth)
4. zygomatic gland: drains near the last upper molar (M2)
what are the 4 muscles of mastication? give origin and insertion and the only species difference for equine
jaw closers (3)
1. temporalis muscle: arises from temporal fossa and inserts on zygomatic arch and mandible
2. masseter muscle: arises from zygomatic arch and inserts on mandible
3. medial and lateral pterygoid muscles: arise from pterygoid fossa and insert on mandible
jaw opener: digastricus muscle: arises from caudal skull and inserts on ventral mandible; in equine has an additional portion (occipitomandibular part) that does not attach to the central tendon; dogs don’t have a central tendon)
describe the intrinsic muscles of the tongue
form tongue shape; fascicles are oriented in different planes to provide full range of motion
list and describe the 3 extrinsic muscles of the tongue
all insert ON the tongue; important for swallowing since they move the food bolus back for swallowing
1. styloglossus muscle: elevates and retracts tongue (pulls caudally)
2. hyoglossus: depresses and retracts the tongue
3. genioglossus: depresses the tongue/pulls tongue down between mandibles
what is another way to describe the rugae of the hard palate?
permanent mucosal folds
describe the incisive ducts of the canine; give a species difference for equine
the left and right incisive ducts pass through the two palatine fissures and open at the lateral sides of the incisive papilla, connecting the nasal cavities with the oral cavity; incisive papilla is a bump but is not a tumor!! don’t remove it dumbass!! (vomeronasal organ joins incisive duct)
in equines the incisive ducts do not open on either side of the papilla
what is the pharyngoespohageal limen?
the junction between the laryngopharynx and the beginning of the esophagus
what two systems share the pharynx? what are the 3 subdivisions of the pharynx?
shared by the digestive and respiratory systems
1. nasopharynx
2. oropharynx
3. laryngopharynx
what are the boundaries of the nasopharynx? describe
nasal choanae to the intrapharyngeal ostium (an opening between the nasopharynx and laryngopharynx formed by the caudal border of the soft palate and the left and right palatopharyngeal arches)
where is the pharyngeal opening of the auditory tube found? what does it lead to?
found in the nasopharynx; leads to the middle ear cavity inside the tympanic bulla
what are the boundaries of the oropharynx? describe
palatoglossal arches to the base of the epiglottis
the palatoglossal arches extend between the body of the tongue and the soft palate
where is the palatine tonsil found?
in the oropharynx beneath a semilunar mucosal fold
what are the boundaries of the laryngopharynx? describe
intrapharyngeal ostium and the base of the epiglottis to the pharyngoesophageal limen
is basically the region dorsal and lateral to the larynx
where are the piriform recesses found? what is their function
found in the laryngopharynx, are laterally positioned pear shaped troughs that channel fluids and possibly aid in vocalization
describe the epiglottis
- valve between airway and oral cavity to the esophagus or larynx
- elastic cartilage with a fat-filled center in the dog = very flexible
- movement is passive and based upon forward movement of the hyoid apparatus and backward movement of the tongue
describe the prehension of horses and cows
cows: prehensile tongue
horses: prehensile lips
both: use dental pads (cows)/incisors (horses)
what are 2 special structures on a cow tongue? describe
- lingual torus: rounded ridge
- lingual fossa: valley before the lingual torus and a common entry point for foreign bodies (when infected = woody tongue)
describe the major salivary glands of cows
- parotid: parotid duct opens near 2nd maxillary molar (maxillary M2)
- mandibular: sublingual caruncles receive ducts for mandibular and monostomatic sublingual glands
describe the major salivary glands of equines
- parotid: parotid ducts open near the 4th maxillary premolar (maxillary PM4)
- mandibular: sublingual caruncles receive ducts for mandibular glands
where does the esophagus move in equines and bovines? clinical application?
begins dorsal to the trachea (like dogs), but moves to the left side of the trachea;
look for visible bulge of the nasogastric tube as it passes through the cervical region on the left side; and can observe food bolus moving up and down the esophagus on the left side in ruminants
what is the anatomical pathway traveled by the nasogastric tube when passed from the nostril to the glandular stomach?
- nostril
- nasal vestibule
- nasal cavity via the ventral nasal meatus
- through the choana into the nasopharynx
- over the larynx into the esophagus
- into the glandular stomach
when passing a nasogastric tube in cattle via a frick speculum or when using a balling gun, what unique anatomic feature of the cow tongue must be passed over when inserting the instrument into the oral cavity?
lingual torus/torus linguae
