Assessment 2 - Dentition small mammals

Question 1

Crown

Answer 1

Above the gumline

Question 2

Root

Answer 2

Below the gumline

Question 3

Enamel

Answer 3

very hard protective outer layer, related to bone

Question 4

Dentine

Answer 4

middle layer, also related to bone but not as hard as enamel

Question 5

Pulp cavity

Answer 5

Inner cavity containing a pulp (living vascular, innervated tissue)

Question 6

Root canal

Answer 6

Where the blood vessels and nerves supply the pulp

Question 7

Cementum

Answer 7

Bony layer which surrounds the root

Question 8

Rooted/ Closed-rooted teeth

Answer 8

Root canal closes and pulp cavity is sealed off (as tooth matures)

Question 9

Rootless/ Open-rooted teeth

Answer 9

Root canal remains open and tooth continues to grow indefinitely

Question 10

Rodent teeth (5)

Answer 10

Single pair of upper & lower incisors

Incisors = open rooted

No canines

Diastema

Pigmented enamel (yellow)

Question 11

Rodent incisors (4)

Answer 11

Enamel - front
Dentine - rear
Incisors chisel agst each other: wear away dentine, leaving sharp enamel edge
Masseter muscles 2 bring lower jaw forward

Question 12

Role of diastema

Answer 12

Manipulation of food inside mouth

Cheeks can be sucked into mouth: closing anterior part of oral cavity (no debris)

Question 13

Class for mouse like rodents

Answer 13

Myomorphs

Question 14

Class for squirrel like rodents

Answer 14

Sciuromorphs

Question 15

Class for porcupine like rodents (guinea pigs, chinchillas, degus)

Answer 15

Hystricomorphs

Question 16

Dentition of myomorphs (2)

Answer 16

16 teeth
Closed-rooted flat molars

Question 17

Sciuromorphs dentition (2)

Answer 17

20-22 teeth
Closed-rooted flat molars

Question 18

Hystricomorphs dentition (2)

Answer 18

20 teeth
Open-rooted flat molars

Question 19

Lagomorph dentition (5)

Answer 19

28 teeth
Open-rooted incisors
Open-rooted flat molars
Diastema

Different to rodents:
Second set of incisors (peg teeth) behind first incisors
No enamel pigmentation

Question 20

Hedgehogs dentition (6)

Answer 20

36-44 teeth
Closed-rooted teeth
Sharp incisors
Lower incisors point forwards
Small, sharp canines
Molars and pre-molars are wide

Question 21

Ferrets dentition (5)

Answer 21

34 teeth
12 small incisors
4 long canine teeth (interlock)
12 pre-molars
6 molars

Question 22

Myomorphs and sciuromorphs diet related teeth? 3

Answer 22

Open rooted incisors
Closed rooted molars
Chisel-shaped incisors
—-
Omnivorous/ herbivorous:
Chisel-shaped incisors: biting hard food materials
Incisors grow all the time
Molars stop growing when mature

Question 23

Hystricomorphs and lagomorphs diet related dentition(4)

Answer 23

Herbivorous:

Chisel-shaped incisors: biting fibrous food

All teeth grow all the time

Flattened molars & lateral/circular moves for grinding down

Question 24

Hedgehogs diet related dentition (5)

Answer 24

Omnivorous (insects mostly):

Forward-facing incisors: pick up small prey

Sharp canines: grasping moving prey

Cusps on premolars&molars: cut through flesh and exoskeletons

Molar = flatter for grinding down plant material

Question 25

Ferrets diet related dentition (4)

Answer 25

Obligate carnivores:

Small incisors: grooming

Long sharp canines: catching/killing prey

Sharp premolars & molars: scissor action to cut and chew meet