Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AASM > 2 - Evolution and Development of Teeth > Flashcards

2 - Evolution and Development of Teeth Flashcards

1
Q

What are the 4 layers that make up a tooth?

A

1) Enamel
2) Dentine
3) Dental pulp
4) Cementum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is contained within the pulp chamber?

A

Dental pulp
Blood vessels
Nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where do vessels and nerves enter / leave the tooth?

A

Apical foramina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What forms the wall of the pulp chamber?

A

Dentine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What two components make up the dentine structure?

A

1) Collagen

2) Calcium hydroxyapatite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What % are both components of dentine present in?

A

Collagen = 25%

Ca-Hydroxyapatite = 75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the function of collagen in dentine?

A

Strength in tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the function of calcium hydroxyapatite in dentine?

A

Strength in compression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the two regions for every erupted tooth?

A

1) Crown (above gingiva)

2) Root (below gingiva)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does the root of the tooth sit?

A

In the alveolus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the outer-most layer of the root region of a tooth?

A

Cementum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the outer-most layer of the crown region of a tooth?

A

Enamel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The composition of cementum is like which other tooth layer?

A

Dentine

i.e. 75-80% mineralised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the composition of enamel?

A

99% mineralised.

very brittle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Tooth development occurs from which developmental origins?

A

1) Ectoderm
2) Neural crest tissue
3) Mesoderm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What cell produces dentine and where is it found?

A

Odontoblasts

In the pulp chamber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What cell produces enamel?

A

Ameloblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where do odontoblasts and ameloblasts initially meet?

A

Enamel-dentine junction (EDJ)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to ameloblasts before tooth eruption?

A

They disappear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What cell produces cementum?

A

Cementoblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How many stages are there to tooth development?

A

6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the names of tooth development stages from early to late?

A

1) Placode stage
2) Bud stage
3) Cap stage
4) Bell stage
5) Crown stage
6) Eruption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The jaw is formed from what embryological structure?

A

First pharyngeal arch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The lower jaw arises from what structure within the first pharyngeal arch?

A

Mandibular prominence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

The upper is formed from two developmental parts. Firstly, how are these split?

A

Mesially (4 incisors)

Distally (canine-> m3)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

The mesial section of the upper jaw arises from what prominence?

A

Frontonasal prominence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

The distal section of the upper jaw arises from which prominence?

A

Maxillary prominence

28
Q

Teeth form as a result of the interaction between which two developmental layers?

A

1) Dental lamina (neural crest)

2) Mesenchyme

29
Q

Which developmental layer invades the other, to form U shaped arches for each tooth?

A

Dental lamina invades the mesenchyme

30
Q

In the bud stage, which developmental tissue is responsible for expressing signals?

A

Dental lamina

31
Q

Signals from the dental lamina result in the expression / inhibition of what transcription factor within the mesenchyme?

A

Pax-9

32
Q

Pax-9 is expressed and inhibited in various areas. What structures result from these differences?

A

Pax-9 expression:
- Tooth development

Pax-9 inhibition:
- Gaps between teeth

33
Q

Where pax-9 is not expressed, another protein is expressed - what is it?

A

Bone morphogenic proteins (BMPs)

34
Q

In the bud stage, what layer forms between the dental lamina and the mesenchyme?

A

Enamel epithelium

35
Q

What two structures form the enamel organ?

A

Enamel epithelium

Dental lamina

36
Q

Within the cap stage, the horizontal side of the enamel epithelium is the site of which cell? To form what structure?

A

Ameloblasts

Forming enamel.

37
Q

What structure is responsible for forming a tooth’s cusp?

A

Enamel knots.

38
Q

At the cap stage, what tissue becomes the primary signalling centre?

A

Mesenchyme

39
Q

What studies have shown the mesenchyme to be the primary signalling centre?

A

Transplant studies of mesenchyme.

40
Q

The mesenchyme can be described as what at the cap stage?

A

Dental papilla

41
Q

What cells does the dental papilla give rise to? What tissue do they go on to make?

A

Odontoblasts

Make dentine.

42
Q

Enamel knots begin acting as signalling centres at the bell stage. What factors are produced WITHIN the knot to stimulate what change?

A

Fibroblast growth factors (FGFs).

Stimulates growth and division.

43
Q

What factor is expressed around the knot and inhibits growth?

A

BMP-4

44
Q

Tooth and jaw growth involves epigenetic interactions between which two structures?

A

Alveolar bone

Tooth roots

45
Q

What effect do tooth roots have on alveolar bone?

A

Stimulate alveolar ossification.

46
Q

What 2 phenotypes occur in MSx-1 k/o mice?

What paper?

A

Normal mandibles

No teeth + no alveolar processes (= undeveloped alveolar bone)

(Satokata and Maas, 1994)

47
Q

In senescence, tooth loss has what effect on the jaw?

A

Reduced demand for alveolar bone to buttress teeth, as a result of lower strain on the jaw, particularly at muscle attachment sites.

ALVEOLAR BONE resorption occurs.

48
Q

Why is alveolar bone resorption particularly bad for ageing individuals?

A

Coupled with osteoporosis, much more likely to fracture.

49
Q

In evolutionary terms, where did teeth most likely arise from?

A

Dermal denticles

50
Q

What evidence supports this, in the context of developmental layers?

A

Both dermal denticles and teeth arise from ectoderm/mesoderm/neural crest contributions.

DON’T contain endoderm.

51
Q

Why might endoderm be thought to be involved in teeth? Contributing to the confirmation that teeth arose from dermal denticles?

A

Oral cavity is a structure that is derived from the bucco-pharyngeal membrane, which degenerates early in development.

Therefore part of GI tract.

GI tract is lined by endoderm.

52
Q

What are the 2 hypotheses for teeth and denticle relationship?

A

Outside-in hypothesis

Inside-out hypothesis

53
Q

What are the 3 reasons for why the outside-in hypothesis is more likely?

A

1) Endoderm labelling shows NO contribution from ENDODERM in mice.
2) Fossil developmental stages support tooth/dermal denticle homology.
3) Fossil basal gnathostomes show dermal denticles are modified as they approach the oral cavity.

54
Q

What are the 3 specialisations of mammalian dentition?

A

1) Mastication - specific to mammals
2) Differentiated dentition (of which there are 4 types)
3) Delayed eruption
4) Fewer sets of teeth

55
Q

What is different about molars in regards to deciduous / adult teeth?

A

Humans ONLY have adult molars - no deciduous versons.

56
Q

Define: monophyodont

Give an example

A

One set of teeth

e.g. Marsupialia

57
Q

Define: diphyodont

Give an example

A

Two sets of teeth

e.g. humans

58
Q

Define: polyphyodont

Given an example

A

Multiple sets of teeth

e.g. Reptilia

59
Q

What occurs to the dental lamina in diphydonts that doesn’t occur in polyphyodonts?

A

Dental lamina fragments and regresses following formation of permanent dentition.

(maintained throughout life in polyphyodonts)

60
Q

What two features characterise the typical mammalian growth pattern?

A

Rapid juvenile growth

Growth cessation at maturity

61
Q

What does the typical mammalian growth pattern allow for?

A

Diphyodonty

62
Q

How do we get around the disadvantages of diphyodonty in early stages of life?

A

Ability to suckle - reduces teeth exposure time, so more likely to stay around for longer.

63
Q

What structure attaches the cementum to the alveolar bone in human adults?

A

Periodontal ligaments

64
Q

(extra reading)

Name 3 important signalling genes?

A

FGF8

BMP4

Shh

65
Q

(extra reading)

What is the role of FGF8 in tooth development?

(K/O studies)

(author?)

A

K/O resulting in large defects in proximal structures derived from 1st pharyngeal arch = teeth, jaws, lateral skull wall, middle ear, part of tongue.

(Trumpp et al., 1999)

66
Q

(extra reading)

What is the role of BMP4 in tooth development?

(Author?)

A

BMP4 antagonises FGFs - where it is expressed, it inhibits FGFs and thus determines tooth location.

(Neubeuser, 1997)

67
Q

(extra reading)

What are the 2 roles of Shh in tooth development?

What has been shown in tooth development from K/O studies?

(author?)

A

Important in crown formation + bud stage of tooth development.

K/O shows deficits in tooth size, morphology and organisation of matrix cells.

(Cho et al., 2011)

AASM (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions