Amelogenesis & Enamel- Exam 1

Question 1

Enamel is considered a ____ tissue

Answer 1

acellular tissue

Question 2

Describe the collagen in the matrix in enamel

Answer 2

not present

Question 3

The formation of enamel involves the secretory and resorptive activities of _____ derived cells

Answer 3

ectodermally

Question 4

Compare the strength of enamel vs. dentin:

Answer 4

enamel is 5x harder than dentin

Question 5

What is the hardest tissue in the body?

Answer 5

enamel

Question 6

The core of enamel is comprised of:

Answer 6

hydroxyappetite crystals

Question 7

The calcium hydroxyappetite crystals in enamel are highly oriented and packed into rod-like structures called:

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 components, 96% inorganic component

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, and Amelogenin

Question 14

Exhibits thixotropic properties (the ability to flow under pressure) and 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 and glycosylated protein & the largest of the enamel matrix proteins.

Answer 16

Enamelin

Question 17

Enamelin is preferentially restricted to the ___ area.

Answer 17

rod area

Question 18

The phosphorylated nature and initial accumulation near the growing ends of crystals suggest that enamelin plays a role in :

Answer 18

crystal growth and nucleation

Question 19

A lengthy protein that helps to connect enamelin and dentin together

Answer 19

tuftelin

Question 20

Tuftelin appears to be restricted to the _____ in enamel tufts.

Answer 20

DEJ

Question 21

This enamel protein is thought to play a role in induction, initiation of mineralization and possible functions as a junctional protein linking enamel and dentin

Answer 21

tuftelin

Question 22

Enamel protein that is initially found throughout the rod and 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 reciprocal induction, the neural crest cells (ectomesenchyme) then induces formation and proliferation of the:

Answer 24

dental lamina

Question 25

During reciprocal induction stage, the ___ eventually spearates into an outer and inner dental epithelium

Answer 25

dental lamina

Question 26

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

Answer 26

odontoblast

Question 27

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

Answer 27

ondontoblasts

Question 28

In reciprocal induction, once the mantle layer of dentin is formed, _____ is initiated and ____ beings shortly thereafter

Answer 28

ameloblast differentiation; amelogenesis

Question 29

The gradient of cellular differentiation, matrix secretion, and mineralization during tooth development is ____ to ____ (dentition), and ___ 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
5. protective stage