Exam 2: Lecture 11: Head & Neck Digestive Pathway Flashcards
What is different about equine lips vs. canine lips?
-Sensitive & mobile, used for selection & apprehension of food
-Upper lip sensitivity used when a twitch is applied, releases endorphins
What is different about equine oral vestibule vs. canines?
-Communicates w/ the oral cavity by the diastema & space caudal to last molar
What is important to note about the palatoglossal arch in equines?
-It is the caudal boundary of the oral cavity
-Joins caudal end of hard palate & root of the tongue
What is the dorsal boundary of the oral cavity in equines?
-Hard palate
What makes up the hard palate of equines?
-Incisive, maxillary, & palatine bones
What is important to note about the equine hard palate?
-Covered w/ a thick mucosa w/ uneven palatine crests, an enlarged palatine venous plexus, & blind incisive papilla
What is different about the incisive papilla in horses than dogs?
-Incisive papilla in equines is present, but a blind sac
What is shown by number 1?
-Incisive papilla
What is shown by number 3?
-Uneven palatine crests
What is the ventral boundary of the oral cavity?
-Tongue
What is the conformation of equine tongues?
-Long & spatulate in its apex
What is shown by number 1?
-Lingual frenulum (narrow in equines)
What structure on the equine tongue gives it a velvet-like surface?
-Filiform papillae
What papillae on the equine tongue are scarce?
-Fungiform papillae
What is circled on the equine tongue?
-Vallate papillae
Where are the vallate papillae located on the equine tongue?
-Between the body and the root
What is the dorsal boundary of the oropharynx?
-Soft palate
What is important to note about the equine soft palate?
-It is elongated & has lymphoid tissue on it
What is the rostral boundary of the oropharynx?
-Palatoglossal arch
What is located between the root of the tongue and the base of the epiglottis?
-Glossoepiglottic fold
What is located on each side of the glossoepiglottic fold and leads to the laryngopharynx?
-Epiglottic vallecula
What do the epiglottic vallecula do?
-Prevents food from going into the airway
What is indicated by the blue star?
-Soft palate
What is indicated by the blue star?
-Palatine tonsil
Where is the laryngopharynx?
-Dorsal to the larynx
What is different about the equine laryngopharynx?
-Lacks pharyngo-esophageal limen (fold)
What are the lateral and rostral boundaries of the oral cavity?
-Equine teeth
Why are equine teeth important?
-Needed to cut, crush, and grind highly fibrous feed stuffs (b/c herbivores)
What type of teeth are found in herbivores and what does the name mean?
-Hypsodont
-Means “long tooth”
What type of teeth are found in carnivores?
-Brachydont (short tooth)
What is different about Hypsodont teeth?
-Teeth continue to erupt throughout life
-“Wear” about 2-3 mm per year (depends on the diet)
What is the “clinical crown” of equine teeth?
-Part of the tooth you can see
What is the “reserved crown” of equine teeth?
-Inside the maxilla bone or mandible
What is the “root” of equine teeth?
-Top part of the tooth in the bone
What is the “anatomical crown” of equine teeth?
-The whole tooth
____ covers the surface of teeth
-Cementum
What forms the peridontal ligament cementing teeth in alveolar bone?
-Cementum
___ forms a layer underneath cement
-Enamel
What does the second involution of enamel in incisors create?
-A cup called the infundibulum
____ is a living, softer layer deep to enamel
-Dentin
What continues to produce new (secondary) dentin throughout life?
-Odontoblasts
What does secondary dentin do?
-Fills in exposed pulp cavity as the tooth is worn down, “dental star”
What is located deep inside the teeth?
-Arteries, veins, and nerves
What type of teeth might or might not errupt in mares?
-Canines
-Found in both sexes but don’t tend to erupt in mares
What is the first premolar?
-Wolf tooth
What is a wolf tooth?
-Small & nonocclusal (not important for grinding)
-May or may not be present
What are the types of equine teeth?
-Incisors
-Canines
-Premolars
-Molars
What are the “cheek teeth”?
-Premolars and molars except wolf teeth
How many incisors are there?
-3 incisors
What is the diastema?
+/- 1 canine (gap between teeth)
How many premolars and molars are there?
-3-4 premolars
-3 molars
What is the dental formula for deciduous teeth?
2 (dI 3/3 : dC 0/0 : dPM 3/3) = 24
What is the dental formula for permanent teeth?
2 (I 3/3 : C 1/1 : PM 4/3 : M 3/3) = 36-42
What are the different incisors called?
-Central
-Intermediate
-Corner
What is important about the 2nd premolar?
-1st “cheek tooth”
What is indicated by the blue star?
-Central incisor
What is indicated by the blue star?
-Intermediate incisor
What is indicated by the blue star?
-Corner incisor
What is indicated by the blue star?
-Wolf tooth (small, only in upper jaw)
Explain the rule of 4 and 9 when talking about equine teeth
-Tooth x04 is ALWAYS the canine tooth (104, 204, 304, 404)
-Tooth x09 is ALWAYS the first molar (109, 209, 309, 409)
What is tooth x06?
-The 2nd premolar (first cheek tooth) of the horse
What numbers are used for deciduous teeth in the equine?
-500, 600, 700, 800
What numbers are given to the upper right, lower right, upper left, lower left equine teeth?
-Upper right = 100
-Upper left = 200
-Lower left = 300
-Lower right = 400
What does “Anisognathus” mean?
-Means the upper arcade is wider and the lower arcade is narrower in equines
What does anisognathus in equines result in?
-Uneven wear of occlusal surface
-“Points” on buccal side of upper cheek teeth and lingual side of lower cheek teeth
What do enamel “points” mean?
-Means there is no wear there
Upper arcade teeth tend to have teeth further ____ than lower arcade
rostral
What is the result of the upper arcade teeth being further rostral than the lower arcade teeth?
-Results in uneven wear & “hooks” on first upper cheek tooth and last lower cheek tooth
____ can prevent hook and point formation and improve the grinding surface of equine teeth
-Regular “floating”
What kind of chewing motion do equines do?
-Circular
What is the most accurate way to age horses using teeth?
-Eruption dates
How do we use eruption dates to age horses?
-Use incisors
-Central incisors erupt at 6 days, intermediate at 6 weeks, corner at 6 months
-Central incisors change to permanent at 2.5 years, intermediate at 3.5 years, corner at 4.5 years
It takes ____ for teeth to erupt to occlusal surface and for enamel to begin to erode
6 months
What is meant when teeth are “level”
-All enamel is in wear (lower & upper jaw)
Cups begin to disappear around what age?
-6 years of age
What is the eruption timeline of canines and cheek teeth?
-Canines: 5 years
-PM: 2, 3, 4 years
-M: 1, 2, 3.5-4 years
What can occur on the mandible or maxilla during the eruption of cheek teeth?
-Eruption bumps or cysts (bony enlargements)
How would you use the length vs. width of the upper corner incisor to age?
-5-9 year: tooth is wider than it is tall
-9-10 year: shape is square (width=height)
->10 year: tooth continues to get taller with age (height > width)
How do we use the angle at which the incisors meet to age horses?
-Upper & lower incisors meet at an upright angle in young horses (round = young)
-As the horse ages, the incisors meet ate a more acute angle (pointy = old)
How do we use the upper corner incision hook to age horses?
-Appears at 7 years & then again at 11 years
-Not very reliable (variable depending on the food the horse eats)
What is circled?
-Upper corner incision hook
Is this an old or young horse?
-Old
Is this an old or young horse?
-Young
How do we use Galvayne’s groove to age horses?
Groove in upper corner incisor:
-Appears at 10 years
-Halfway down at 15 years
-All the way down the tooth at 20 years
-Halfway gone at 25 years
-All the way gone at 30 years
How old is this horse based on the Galvayne groove?
-10 years ish
How old is this horse based on the Galvayne groove?
-20 years ish
What decreases with age after completing the formation around 5 years of age in equine teeth?
-The length of reserve crown
What is the best aging by teeth rule of thumbs?
-6 days, 6 weeks, 6 months
-2.5, 3.5, 4.5 years
(eruption)
How does the relationship of the teeth and sinuses change as the horse ages and the teeth are worn?
-Adult horses: Roots of PM4/M1 are within the rostral maxillary sinus
-M2/M3 are within the caudal maxillary sinus
What is shown by number 2?
-Sublingual caruncles
