Amelogenesis- EXAM I

Question 1

Enamel is considered a ____ tissue

Answer 1

Acellular

Question 2

Describe the collagen in the matrix of enamel:

Answer 2

No collagen

Question 3

Formation of enamel involves the secretory & resorptive activities of ____ derived cells

Answer 3

Ectodermally

Question 4

Compare the strength of enamel vs. dentin

Answer 4

Enamel is 5x harder

Question 5

What is the hardest tissue in the body?

Answer 5

Enamel

Question 6

The core of enamel is composed of:

Answer 6

Hydroxyapatite crystals

Question 7

The Ca hydroxyapatite crystals in enamel are highly oriented & packed into rod-like structures called the ____

Answer 7

Enamel rods

Question 8

Although 96% mineral, the basic rod structure of enamel exhibits some degree of _____

Answer 8

Flexibility

Question 9

Describe the orientation of enamel rods:

Answer 9

Parallel to the long axis

Question 10

Describe the composition of enamel:

Answer 10

1% water
3% organic compounds
96% inorganic components

Question 11

What comprises the inorganic component of enamel?

Answer 11

Calcium hydroxyapatite

Question 12

What is the main protein comprising the organic component of enamel?

Answer 12

Tyrosine-rich amelogenin protein (TRAP)

Question 13

What components make up TRAP?

Answer 13

Tuftelin
Sheathlin
Enamelin
Ameloginin

Question 14

Exhibits thixotropic properties (the ability to flow under pressure) & comprises most of TRAP

Answer 14

Amelogenin

Question 15

Considered one of the largest of the TRAP proteins:

Answer 15

Enamelin

Question 16

An acidic, phosphorylated & glycosylated protein & the largest of the enamel matrix proteins

Answer 16

Enamelin

Question 17

Enamelin is preferentially restricted to the _____ area

Answer 17

Rod

Question 18

The phosphorylated nature & intital accumulation near the growing ends of crystal suggest that enamelin plays a role in:

Answer 18

Crystal growth & nucleation

Question 19

A lengthy protein that helps to connect enamelin and dentin together

Answer 19

Tuftelin

Question 20

Tuftelin appears restricted to the ____ in the enamel tufts

Answer 20

DEJ

Question 21

This enamel protein is thought to play a role in induction, the initiation of mineralization & possibly functions as a junctional proteins linking enamel & dentin

Answer 21

Tuftelin

Question 22

Enamel protein that is initially found throughout the rod & interrod enamel, however it is preferentially located in the rod sheaths:

Answer 22

Sheathlin

Question 23

In the reciprocal induction stage, the pre-tooth bud stage ectoderm specifies the “dental nature” of the:

Answer 23

Underlying mesenchyme (neural crest cells)

Question 24

In the reciprocal induction stage, the neural crest cells (ectomesenchyme) then induces formation & proliferation of the ______

Answer 24

Dental lamina

Question 25

During the reciprocal induction stage, the _____ eventually separates into an outer & inner dental epithelium

Answer 25

Dental lamina

Question 26

In reciprocal induction, the inner enamel epithelium induces differentiation of:

Answer 26

Odontoblasts

Question 27

During reciprocal induction, the ____ secrete the mantle layer of dentin

Answer 27

Odontonblasts

Question 28

In reciprocal induction, once the mantle layer of dentin is formed, ______ is initiated & _____ begins shortly thereafter

Answer 28

Ameloblast differentation
Amelogenesis

Question 29

The gradient of cellular differentiation, matrix secretion & mineralization during tooth development is ____ to ____ (dentition) & ____ to ____ (individual teeth)

Answer 29

Anterior to posterior
Coronal to apical

Question 30

List the stages of ameloblast function (5):

Answer 30

1. Morphogenic stage
2. Differentiation stage
3. Secretory stage
   4, Maturation stage
4. Protective stage