Tooth Development & Structure Flashcards
1
Q
Formation of a ball of cells, called the
A
Mourula
2
Q
Fluid accumulates In the morula; its cells realign themselves
Formation of a fluid-filled hollow ball, called the
A
blastocyst
3
Q
The cells on the outer later of a blastocyst are called?
A
Trophoblasts
4
Q
The cells on the inner layer of a blastocyst are called?
A
Embryoblasts
5
Q
The human mourla developes rapidly within days following ?
A
Fertilization
6
Q
On day 5 of development, the human blastocyst contains what?
A
- Zona pelucida
- Trophoblast
- Blastoceal (yolk salk)
- Embryoblast
7
Q
What is another word for the yolk sack?
A
Blastocoel
Coel=hole
8
Q
What an egg is fertilized how long does it take to become a mourla? then a Blastocyst?
A
Moural= day 3/4
Blastocyst= 5/6
9
Q
At day 8 after fertilization, the inner cell mass ____ differentiates into 2 groups of cells.
A
Embryoblast
10
Q
What are the 2 groups of cells which the embryoblast layer differentites into?
A
- Epiblast
- Hypoblast
11
Q
At the stage in which the embryoblast differentiates into the epiblast and hypoblast layer this is a a ____
A
Bilaminar embryonic disk
2 layer embryonic disk
12
Q
In Bilaminar Germ Disk
are columnar and reorganize to form the amniotic cavity
A
Epiblasts Cells
13
Q
The epiblast cells will reorganized itself to form the ____ and ____ linnig the amniotic cavity
A
- Forms embryo
- Forms epithelilial layering lining the amniotic cavity
14
Q
The epiblast layer will form the entire embryo and undergoes gastrulation in week three to form the what?
A
3 germ layers
15
Q
In Bilaminar Germ Disk
are cuboidal and form the roof of the secondary yolk sac
A
Hypoblast cells
16
Q
In week three, the hypoblast layer is replaced by the gastrulation migrating
A
Endoderm cells
17
Q
The hypoblast layer is considered a
A
A primitive “endoderm”
Not true; only precourssor
18
Q
The epiblast layer is considered a what?
A
Primative ectoderm
Not true; only precoursor
19
Q
Summary
A
Summary
20
Q
Formation of the true germ layers
is the beginning of morphogenesis (development of body form) and is the significant event occurring during the third week.
A
Gastrulation
21
Q
During gastrulation, the bilaminar embryonic disk is converted into a ?
A
trilaminar embryonic disk
22
Q
development of body form
Occurs during gastrulation
A
morphogenesis
23
Q
During gastrulation, ____ is established in the embryos
A
axial orientation
Develop head and tail orientation
24
Q
refers to the anterior (front) aspect of the embryo
A
Ventral
25
refers to the posterior (back)
Dorsal
26
relating to the head
Cephalic
27
Relating to the tail or back of head
Caudal
28
is a transient embryonic anatomy structure required for patterning the surrounding tissues.
Notochord
29
# Neuroembryological terms
are only used to describe **structures within the central nervous system**, above the level of the spinal cord (e.g., brainstem, cerebrum and cerebellum).
Roastral and Caudal
30
refers to the anterior (front) aspect of the head.
Rostaral
31
dorsal refer to the anterior and posterior aspects of **the body**, respectively.
Ventral (front), Dorsal (back)
32
In the brain, ventral refers to what?
inferior region of the brain
33
In the brain, dorsal refers to what?
refers to the superior region (towards the scalp).
34
Cells of the epiblast divide and migrate toward the
The primative streak
35
Cells of the epiblast divide and migrate toward the primitive streak.
**displace and replace the hypoblast cells** and become the what?
True embryonic endoderm
36
Cells of the epiblast divide and migrate toward the primitive streak.
they can also pack themseleves between the newly formed embryonic endoderm and epiblast to form the ?
Mesoderm
37
the remaining cells of the epiblast are the?
Ectoderm
38
Gastrulation views
Gastrulation Views
39
Following the for mation of the triboblastic embryo, for the next 3-4 weeks what develops?
**Major tissue development**
include the head, face, and tissues contributing to **development of the teeth.**
40
What layer of cells do teeth develop from?
Ectoderm
41
Issues of the skin, hair, pigment, neurological issue are clinical manifestions of what?
Issues with emrbyological developmen of the ectoderm
42
# What layer?
* Skin cells of epidermis
* Teeth
* Nueron of brain
* Pigment cells
Ectoderm
| External layer
43
# What layer?
* Cardiac muscle
* Skeletal muscle cells
* Tubule cell of the kidney
* RBC
* Smooth muscle in gut
Mesoderm
| middle layer
44
# What layer?
* Lung cells
* Thyroid cells
* Pancreatic cells
| Gut
Endoderm
| interior layer
45
# 3 key events
What are 3 key events of the formation of the neural tube and fate of germ layers?
1. Differentiation of nervous systema nd neural crest tissue from **ectoderm**
2. Diferentiation of mesoderm
3. Folding of embryo in 2 planes (rostral-caudal) & (lateraly)
46
At weeks 6-8 of embryonic development, the ____ is formed from ectoderm.
neuroectoderm
| Eventually froms the brain
47
A group of cells **separate from the neuroectoderm**. These are
Neural Crest Cells
48
**Embryonic connective tissue** elsewhere is derived from **mesoderm** and is known as
Mesenchyme
49
**Embryonic connective tissue **in the **head** is derived from **mesoderm** and is known as
ectomesenchyme
| "Periodontum (connective tissue) is ectomesychimally derived"
50
Produced from the fusion of the neural fold beneath the surface of the ectoderm
Neural tube
51
Anteriorly, the neural tube expands to form what 3 things?
1. Forebrain
2. Midbrain
3. Hindbrain
52
develops a series of 8 bulges (the rhombomeres)
Hindbrain
53
The posterior neural tube developes into the?
Spinal cord
54
A series of externally visible tissue bands
Give rise to the structures of the head and neck
Pharyngeal Arches
55
Cranial neural crest-derived **mesenchymal cells** **(ectomesenchyme)** migrate into pharyngeal arches from midbrain and hindbrain region forming what 6 kinds of cells?
1. Neurons
2. Schwann cells
3. Smooth muscle cells
4. Osteoblasts
5. Chondrocytes
6. Odontoblast
56
Cells that form teeth
Odontoblasts
57
58
Abnormalities in the head and face are a result of issue with ___ ___ cells in head and neck formation during embryological formation
neural crest cells issue
59
The underdevelopment results from a **Failure of the neural crest cells to migrate to the facial region**.
* Drooping eyes
* Bad hair
* bad teeth
* Bad skin
* neurological defects
Treacher Collins syndrome
60
able to develop into the tissues of the l**ymphatic and circulatory systems**, as well as **connective tissues throughout the body**, such as bone and cartilage.
Mesenchyme
61
Most of the time, mesenchyme is derived from the ____ but, in certain exceptional cases, the mesenchyme may be derived from the ____ (from neural crest cells) [ectomesenchyme].
**Mesoderm derived** = mesenchyme
**Ectoderm derived** from neural crest cells= ectomesencym
62
Neural crest cells eventually from what in moutth?
Connective tissue!
* PDL
* Alevolar bone
* Dentin
etc
| surface ectodern
63
Enamel Formation
AMELOGENESIS
64
Cells: **ameloblasts**
**Ectodermal origin**
Amelogenisis
65
What cells help in enamel fromation?
Amenoblasts
66
Dentin-Pulp complex formation
Dentinogenisis
67
Cells: **odontoblasts**
**Ectomesenchymal origin**
Dentinogenisis
68
What cells aid in dental pulp complex formation?
Odontoblasts
69
Cementum formation
SUPPORT TISSUES FORMATION
70
Cells: **cementoblasts**
**Ectomesenchymal origin**
Support tissue formation (cementum)
71
What cells aid in cemenetum formation?
cementoblasts
72
What are the 3 overlapping phases of tooth development?
1. Inititation (est. site of future teeth)
2. Morphogenisis (det shape of tooth)
3. Histogenisis (fully formed dental tissue via cell differentiation)
73
# What stage of tooth dev?
Establish sites of future teeth.
Initiation
74
# What stage of tooth dev?
Determine shape of tooth.
Morphogenisis
75
# What stage of tooth dev?
Fully formed dental tissues via cell differentiation.
| Amenoblast, cementoblast, odontoblast start to develop
Histogenisis
76
During inital embryological development there are designated areas for both __ and ___.
Primary and permanent teeth.
All teeth are pre-formed. (primary 1st, secondary later)
**why mothers health during pregnancy affects in child**
77
What are the 3 stages of tooth formation?
* Bud
* Cap
* Bell
78
Inward growth onto the underlying ectomesenchyme the on each thickened epithelial shelves
| Signals beggining of tooth development
Dental Lamina
| S
79
The ____ thickens into dental lamina, and ectomesencyme cells migrate around it
| Primary epithelial band
Outer epithelium thickens to from dental lamina.
80
Explain A and B
Dental lamina (B)- lingually located
Vestibular lamina (A)- buccally located
**thickening of dental OE itno dental lamina singals tooth development initiation**
81
are embryonic structures that give rise to structures such as hair follicles and teeth
**form along dental lamina, signal where bud will form**
Dental Placode
82
*Condensation!*
**first epithelial incursion into the ectomesenchyme of the jaw.**
Cells show little change in shape or function.
Bud stage
| Tooth grows inward into jaw, mesenchyme cells migrate toward bud
83
Bud stage, explain A and B
A= enamel organ; dental lamina
B= (ecto)mesenchymal condensation
84
During the bud stage is there differentiated cells?
NO! only group of condensed cells. Differentiation is in cap stage!
85
Marks the **onset of morphologic differences between tooth** germs that give rise to **different types of teeth.**
Bud-to-Cap transition
86
Explain
| Cap Stage
**Cap Shaped**; developing tooth, contain enamel organ, cervical loop transition from inner and outer enamel epithelium.
Cervical loop grow and trap dentin
Inner= dentin
Closer to middle= pulp tissue of teeth
87
is a cellular aggregation seen in a developing tooth and it lies above the dental papilla.
Enamel Organ
88
At the **periphery of the enamel organ**, the cells assume a **low cuboidal shape** and form the
Outer Enamel Epithelium
89
The cells **bordering on the dental papilla** assume a **short columnar shape** and are characterized by **high glycogen content**
Inner enamel Epithelium
90
center of the enamel organ
Stellate reticulum
91
In the bell stage, some epithelial cells **between** the inner enamel epithelium and the stellate reticulum **differentiate into a layer** called the
Stratum Intermedium
92
region where the **inner and outer enamel epithelia meet** at the rim of the enamel organ is known as the
Cervical loop; roots
93
ball of condensed ectomesenchymal cells which will eventually form the dentin and the pulp of the tooth.
Dental papilla
94
The condensed ectomesenchyme**limiting the dental papilla and encapsulating the enamel organ**
gives rise to the **supporting tissues of the tooth**
Dental follicle
95
The
* enamel organ
* dental papilla, and
* dental follicle together constitute the?
Tooth germ (dental organ)
96
tologic slide showing a tooth bud.
What is A B C?
* A: enamel organ
* B: dental papilla
* C: dental follicle
97
What does this slide display?
Early cap stage of tooth development (arrows).
A = Meckel's cartilage;
B = developing tongue
98
# early cap
What does the cap stage start with?
cellular differentiation **within the enamel organ.**
99
# early cap
During histodifferentiation in the cap stage, central cells in the enamel organ form the?
Stellate Reticulum
100
# early cap
During histodifferentiation in the cap stage, **epithelial cells** differentiate into what 2 kinds of cells?
inner and outer enamel epithelia.
101
During the late cap stage what 5 things have formed?
* A = stellate reticulum
* B = outer enamel epithelium
* C = inner enamel epithelium;
* D = dental papilla;
* E = dental follicle (everything around cap; future pdl)
102
By the bell stage is the tooth type decided?
Yes!
103
During this stage, the cells that will be making the hard tissues of the crown (**ameloblasts and odontoblasts**) acquire their distinctive phenotype (histodifferentiation), and the **crown completes its morphodifferentiation and attains its full size.**
Bell Stage
104
# Early bell
What is A and B?
A = inner investing layer of dental follicle;
B = outer layer of dental follicle
105
During the **early bell stage** what does the **dental papilla look like** in comparatison to how it was in the cap stage?
Dental Papilla is more invaginated and condensed
106
# Early Bell
What tooth class will this be?
Incisor
107
is a **permanent tooth** that replaces a **primary (deciduous) tooth**.
succedaneous teeth
108
Permanent Incisors, Canines, and Premolars are what type of dentition?
succedaneous teeth
| Note tooth bud of permanent tooth forming
109
What is the only class of permanent dentition that are not succedaneous?
Molars! They are brand new.
110
# What stage of tooth dev?
Formation of buds on mandible and maxilla
Initiation
111
When permanent molars form do they have teeth around them? Why?
No! because they are not succedaneous. Form alone
112
Explain why primary teeth roots bend buccally.
In development,** primary tooth bud is buccal** and **permanent tooth bud is lingual**.
113
Review Stages of tooth Dev.
