GI - Teeth Revision

Question 1

What does heterodont mean?

Answer 1

All the teeth are different (mammals and some reptiles)

Question 1

What does homodont mean?

Answer 1

All teeth the same (e.g reptiles and fish)

Question 2

What does hypsodone mean?

Answer 2

High crowns (equines and bovids where you can only see the tip of the tooth)

Question 3

What does brachydont mean?

Answer 3

Low crowns (carnivorous mammals)

Question 4

What does diastema mean?

Answer 4

The gap between the incisors and cheek teeth (normal in herbivores)

Question 5

What is the difference between the gingiva and mucogingival line?

Answer 5

Gingiva (gum) = tightly attached to bone

Mucogingival line = above this line, oral mucosa becomes loose.

Question 6

How to carnivores move their jaw?

Answer 6

Move jaw sideways to engage carnassial teeth (big ones at the back of the mouth).

Close jaw to shear/crush.

Question 7

How do omnivores move their jaw?

Answer 7

Combined crush/grind action.

Question 8

How do herbivores more their jaw?

Answer 8

Close jaw on herbage -> move jaw sideways while held close to grind plant material.

Question 9

What does secodont mean?

Answer 9

Staggered teeth food for gripping hard and soft objects (carnivores)

Question 10

What are the trident system starting numbers for deciduous and permanent teeth?

Answer 10

Deciduous = 5,6,7,8

Permanent = 1,2,3,4

Question 11

In what order at the teeth starting from cranial to caudal?

Answer 11

Incisor, canine, premolar, molar

Question 12

What is the crown, root and peridonteum?

Answer 12

Crown = exposed part

Root = buried part

Peridontium = supporting structures

Question 13

What are the five layers to the tooth?

Answer 13

1. Enamel
2. Dentine
3. Cement
4. Pulp
5. Nerve

Question 14

What are the three layers to the peridonteum?

Answer 14

1. Periodontal ligament
2. Alveolar bone
3. Gingiva

Question 15

What are the key features of enamel?

Answer 15

• Hardest structure
• Cannot repair (tooth appears off white when damaged)
• Only on the crown
• Not alwaysys present

Question 16

What are the key features of dentine?

Answer 16

• Living tissue (odontoblasts)
• Primary (most, mineralised collagen)
• Secondary (formed after eruption, continues to grow, decreases size of pulp)
• Tertiary (reaction to damage)

Question 17

What are the key features of cementum?

Answer 17

• Similar to bone
• Attached to perdiontal fibres
• Laid down on annual basis (ridges)
• Completely covers herbivores teeth

Question 18

What are the key features of pulp?

Answer 18

• Feeds odontoblasts
• Contains blood vessels, lymph, nevres
• Narrows with age as dentine deposition occurs
• Closed apex (when finished erupting)
• Open apex (when continually erupting)

Question 19

What is the role of the peridontium

Answer 19

Attach, support, protect

Question 20

What are closed roots?

Answer 20

Root apex has closed off (= no more growth)

Horses/cattle = tooth erupts slowly and continously

Carnivores = teeth erupt to fixed height

Question 21

What are open roots?

Answer 21

Root apex is open, tooth grown continuously and erupts (e.g. rodent incisors).

Question 22

At which stage to horses and carnivores teeth erupt?

Answer 22

Horses - teeth erupt as they grow and the roots close later in life. Continuously erupt for life.

Carnivores - teeth erupt as they finish growing. Erupt until a fixed height.