The Oral Cavity

Question 1

List the spaces in oral cavity

Answer 1

Oral cavity proper: between teeth (communicates with pharynx)
Oral vestibule: between cheek and teeth
Cheeks: lateral wall of mouth-buccinator muscle

Question 2

Structure of the palate

Answer 2

Hard palate is rostral to the soft palate
Muscles are covered with mucous membrane (musculomucosal)
Closes the nasal passage when swallowing

Question 3

Hard palate

Answer 3

Keratinised for protection
Ridges for gripping food
Maxilla and premaxilla mucous membranes
Incisive Papillae- sense of smell and taste- olfactory receptor.

Question 4

Vomeronasal Organ

Answer 4

Incisive papilla open into incisive duct- links mouth with the nasal cavity
Keratinised epithelium
Near vomer and palatine processes of incisive and maxillary bones
For pheromone detection

Question 5

Structure of the tongue

Answer 5

Covered with stratified squamous epithelium
Attached to hyoid bone and mandible
Projections: papillae and taste buds
Lyssa: central midline cord of skeletal muscle and adipose tissue

Question 6

List the tongue muscles

Answer 6

Intrinsic m. (Lingualis Proprius)
Extrinsic m.
Stylo-glossus
Hyo-glossus
Genio-glossus

Question 7

Intrinsic m. (tongue)

Answer 7

oriented- longitudinal, transverse and vertical
forms tongue proper ( curl, groove)

Question 8

Extrinsic m. (tongue)

Answer 8

Three pairs have osseous origin
Parallel to each other
Lateral to medial in following order

Question 9

Stylo-glossus

Answer 9

Long thin muscle
Elevates the tongue

Question 10

Hyo-glossus

Answer 10

Wide and flat muscle
Retracts and depresses the tongue

Question 11

Genio-glossus

Answer 11

Fan-shaped muscle
Caudal fibers protrude
Rostral one retract the apex

Question 12

What are the types of lingual papillae

Answer 12

Mechanical and Gustatory (taste)

Question 13

Types of mechanical lingual papillae

Answer 13

FILIFORM: hair-like structures on dorsal surface, grips food
CONICAL: larger, less frequent. Movement of food, inside lips and cheeks
MARGINAL: Newborn carnivores and piglets- aid in suckling
LENTICULAR: hard and horny due to heavy keratinisation

Question 14

Types of gustatory lingual papillae

Answer 14

FUNGIFORM: among filiform over rostral 2/3 of dorsum of tongue- mushroom shaped
VALLATE: between body and root of tongue- circular projections surrounded by deep groove
FOLIATE: On edge of tongue- found in horses and pigs

Question 15

How is the tongue innervated?

Answer 15

Motor and sensory
MOTOR: hypoglossal nerve (CN XII) supplies intrinsic and extrinsic muscles
SENSORY: rostral 2/3- lingual nerve branch of mandibular division of trigeminal nerve (CN V); SENSATION
chorda tympani branch of facial nerve; TASTE
caudal 1/3- glossopharyngeal nerve (CN IX); GENERAL TASTE AND SENSATION
additional innervation from vagal nerve

Question 16

Two dental arcades

Answer 16

Heterodont- I, C, PM, M
Dipphyodont- deciduous and permanent

Question 17

What is the borderline between crown & root called?

Answer 17

The Cementoenamel junction (CEJ)

Question 18

Socket of bone tooth is rooted into is…

Answer 18

the alveolus

Question 19

Thin shell of dense bone lining the alveolus is…

Answer 19

the Lamina dura

Question 20

What is the pulp cavity?

Answer 20

Central space of tooth, contains pulp soft tissue- with nerves, vessels and lymphatics

Question 21

How is the tooth root attached to the bone?

Answer 21

Connective tissue called the periodontium- connected via periodontal ligaments

Question 22

What are 4 defined structures in periodontal tissue?

Answer 22

• Gingiva
• Cementum
• Alveolar bone
• Periodontal ligament

Question 23

Gingiva

Answer 23

the gums: one of 4 periodontal tissues
-have attached gingiva and free gingiva
- at the sulcus cells in epithelium of the gum adhere to the tooth enamel via basement membrane

Question 24

Brachydont

Answer 24

Smaller & low-crowned
Feeding on a soft diet
Seen in dogs, cats, pigs etc.
True root

Question 25

Hypsodont

Answer 25

Larger crown to resist wear and tear
Fed on a tough and fibrous diet
Seen in horses and ruminants

Question 26

Enamel

Answer 26

Sometimes called Ameloblast
hardest substance in body
acellular so cannot regenerate
in brachydont- covers only crown
in hypsodont- covers entire body of tooth except root

Question 27

Dentin

Answer 27

Sometimes called odontoblast
forms the bulk of the tooth
surrounds the pulp cavity
remain active through life

Question 28

Cementum

Answer 28

Least hard of all, thin bonelike layer
Brachydont covers only root
Fills the infundibula of hypsodont teeth and covers entire tooth

Question 29

Functions of the teeth

Answer 29

-Incisors: adapted for grasping, pinching, scratching and nipping
-Canines: “weapons” for tearing flesh
-Premolars: rostral cheek teeth; deciduous precursors
-Molars: flattened with jagged edges like serrated blades

Question 30

Surfaces of teeth

Answer 30

Labial; near lips
Lingual; facing the tongue
Mesial; towards median plane
Distal; away from median plane
Occlusal; top surface

Question 31

Pig teeth

Answer 31

44 permanent teeth
6x incisors
2x canines
8x premolars
6x molars

Question 32

Dog teeth

Answer 32

Missing upper 3rd molars so has 42 teeth
- all incisors have a single root
- PM1s have single root
- PMs and Ms have double root
- Upper PM4 & 2x upper Ms have 3 roots
-lower M3 has one root

Question 33

Ruminant teeth

Answer 33

No upper incisors/canines- dental pad
incisors and canines are brachydont
premolars and molars are hypsodont

Question 34

Horse teeth

Answer 34

Incisors- high crowns single root
Canines- often don’t erupt
Hypsodont; continuous wear, slowly erupt

Question 35

Horse teeth

Answer 35

Incisors- high crowns single root
Canines- often don’t erupt
Hypsodont; continuous wear, slowly erupt

Question 36

Infundibulum

Answer 36

Cup-shaped invagination of enamel from the occlusal surface of equine incisors or maxillary cheek teeth
Partly filled with cement
Doesn’t connect to pulp cavity

Question 37

Lagomorphs

Answer 37

Rabbits have 2x small second incisors called peg teeth behind maxillary incisors
Incisors and cheek teeth are hypsodont
Elodont; continuously growing

Question 38

Blood supply

Answer 38

• Maxillary artery; terminal branch of the external carotid

Question 39

What artery supplies blood to upper teeth?

Answer 39

the infraorbital artery

Question 40

What artery supplies blood to lower teeth?

Answer 40

the inferioralvelolar artery (IAA)
enters mandible through mandibular foramen into mandibular canal

Question 41

Nerve supply

Answer 41

The trigeminal nerve (CN V) supplies sensory innervation to teeth through maxillary and mandibular divisions

Question 42

How are upper incisors innervated?

Answer 42

By infraorbital n. which runs in infraorbital canal

Question 43

How are mandibular teeth innervated?

Answer 43

By inferioralvelolar n. which runs in mandibular canal

Question 44

Functions of salivary glands

Answer 44

• Lubrication and binding
• Antibacterial
• Enzymatic digestion
• pH regulation
• Thermoregulation
• Urea for protein synthesis in fore-stomach

Question 45

Major salivary glands

Answer 45

-via long ducts
eg. parotid, mandibular and sublingual

Question 46

Minor salivary glands

Answer 46

-via short ducts
eg. labial, lingual and buccal

Question 47

Acini

Answer 47

Salivary glands are made up of secretory acini and ducts
-serous acini; secretes proteins in an isotonic watery fluid
-mucous acini; secretes mucin (lubricant)

Question 48

Parotid gland

Answer 48

Located ventral to the ear
Vascularised by branches of maxillary a.
Innervated by glossopharyngeal n.

Question 49

Mandibular gland

Answer 49

Ventral to parotid gland, caudal to mandible bone
Vascularised by branches of linguofacial a. and v.
Innervated by facial n.
Shares a capsule with sublingual gland

Question 50

Sublingual gland

Answer 50

Located under the tongue
Monostomatic part: more caudal, single draining duct
Polystomatic part: more rostral with several small ducts
Vascularised by lingual a. and v.
Innervated by facial n.