Neural Crest Cells
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

www.indiandent...
“He who sees things grow from the beginning
will have the finest view of them”
-Aristotle

www.indiandentalacademy.com
Fertilization
It is sequence of events that begins with
contact between a sperm and a oocyte
and finally ends with the fus...
Cleavage
It is a process by which zygote
undergoes a series of rapid mitotic
division.
First the zygote divides into two c...
Zygote showing the process of
cleavage

www.indiandentalacademy.com
Time: The division starts 30 hours after
fertilization.
Site: This occurs as the zygote passes
along the uterine tube towa...
www.indiandentalacademy.com
Important point:
There is increase in the number of cell
without an increase in the cytoplasmic
mass as a result of which ...
Morula
This is so called when the number of
cells becomes 16
Time: 3-4 days after fertilizations
Site: Uterus
www.indiande...
Morula

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BLASTOCYST
Space appear between the central
Blastomeres of Morula. This space gets
filled with the fluid from the uterine ...
Blastocyst

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BLASTOCYST
Following this fluid – filled spaces fuse to
form a single, large blastocyst cavity.

Blastocyst
www.indiandent...
Implantation
Time: After six days
The blastocyst attaches itself to the
endometrial epithelium, adjacent t the
inner cell ...
Implantation
As this occurs the trophoblast start
proliferating rapidly
cytotrophoblast

syncytiotrophoblast

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Implantation of the blastocyst

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Implantation
Finger like processes of
syncytiotrophoblast extend through the
endometrial epithelium
Time:by the end of the...
Completion of implantation
Time: the process of implantation is
completed by the end of second week.

As the blastocyst sl...
Formation of the amniotic
cavity
As the implantation is progressing small
cavity appears at the embryonic pole
between emb...
Developing amniotic cavity

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Formation of Bilaminar plate
At the same time morphologic changes
occur in the embryoblast resulting in the
formation of c...
Bilaminar plate

www.indiandentalacademy.com
Formation of the primary yolk
sac
Few cells from the hypoblast migrate to
form a membrane called exocoelomic
membrane
This...
Primary yolk sac

www.indiandentalacademy.com
Formation of the secondary
yolk cell
Some cells from the hypoblast gives rise
to a layer of loosely arranged tissue
called...
Development of the secondary
yolk sac

www.indiandentalacademy.com
Development of chorionic sac
Extra embryonic coelom splits the extra
embryonic mesoderm into two layers

Extraembryonic
So...
Development of chorionic sac
Extra embryonic Somatic mesoderm

+

Two layers of trophoblast

Chorion
www.indiandentalacade...
Chorionic sac

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Prochodral plate
Time:around the 14th day
few hypoblastic cells change into
columnar shape and form a thickened
,circular ...
Prochodral plate

www.indiandentalacademy.com
The third week
Gastrulation.
Primitive streak.
The notochordal process.
Notochord.
Neuralation.
The neural crest cells.
ww...
Gastrulation
It is process by which the bilaminar
embryonic disc is converted into a
trilaminar embryonic disc resulting i...
Primitive streak
It is a thickened linear band of epiblast
which appears caudally in the median
plane and on the dorsal as...
Primitive node

www.indiandentalacademy.com
Germ layers
Mesoblast/Mesenchyme--mesoderm
Primitive streak cell
displace hypoblast -- endoderm
Epiblast

-- ectoderm

www...
Developing germ layers

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Notochordal process
Some mesenchymal cells migrate
cranially from the primitive node to form a
median cellular cord known ...
The notochordal process
prochordal plate

Notochordal canal

cloacal membrane
www.indiandentalacademy.com
Formation of the notochord
It is a cellular rod that develops by
transformation of notochordal process
- defines the primi...
Formation of the notochord
1. As notochordal process elongates

,notochordal canal extends cranially
from primitive node t...
Developing notochord

www.indiandentalacademy.com
Formation of the notochord
4. The opening rapidly becomes confluent
and notochordal canal disappears .

5. Beginning at cr...
www.indiandentalacademy.com
Neuralation
It is process involved in the formation of
the neural plate and neural folds and the
closure of these folds to...
Neural plate
As the notochord develops ,embryonic
ectoderm over it thickens to form the
neural plate-neuroectoderm.
Around...
www.indiandentalacademy.com
The neural crest
Some neuroectodermal cells lying along
the crest of each neural fold lose their
epithelial affinities and...
www.indiandentalacademy.com
www.indiandentalacademy.com
Characteristics of the neural
crest cells
I.
II.

Pleuripotent capability –is the ability of
these cells to give rise to s...
Characteristics of the neural
crest cells
Migration
Active

Passive

Without the
ectoderm

With the
ectoderm

www.indiande...
Factors affecting migration
1. Extra cellular molecules- such as
fibronectin are encountered along the
way of migration ar...
Factors affecting migration
3) Drugs-isotretenion(13-cis-retinoic
acid)cause sever malformations by
affecting the neural c...
Characteristics of the neural
crest cells
III. Regulation- reffers to the ability of an
embryo to compensate for the loss ...
Study done by BonnerFraser(1986)
CSAT antibody was used
Antibody was injected in embryonic chicks
just before the initiati...
Study done by BonnerFraser(1986)
24 hrs later-defective proliferation.
defective initiation of migration.
defective direct...
Characteristics of the neural
crest cells
IV. Cessation-reffers to the property of the
Ncc to cease the process of migrati...
Structure derived by the neural
crest cells
I.

Connective tissue- Ectomesenchyme of facial
prominences and brachial arche...
Structure derived by the neural
crest cells

II.

-Dental papilla
-Portions of periodontal ligament
-Cementum
Muscle tissu...
Structure derived by the neural
crest cells
III. Nervous tissue-

-Leptomeninges.
-Schwan sheath cells.
IV. Sensory gangli...
Structure derived by the neural
crest cells
VI. Endocrine tissue-

-Adrenomedullary cells
-Calcitonin ‘c’ cells
-Carotid b...
Dental context
1. The initiation of the tooth formation.
2. The determination of the tooth's crown
3.
4.
5.
6.

pattern.
T...
Clinical implications
1. Treachers Collins syndrome.
2. Hemifacial Microsomia.
3. Limb abnormalities.

www.indiandentalaca...
Treachers Collins Syndrome

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Hemifacial Microsomia

www.indiandentalacademy.com
Summary of events
Zygote

Morula
Blastula
Implantation
Amniotic cavity

www.indiandentalacademy.com
Summary of events
Bilaminar embryonic disc
Yolk sac
Chorionic sac
Germ layers
Primitive streak

www.indiandentalacademy.co...
Summary of events
Notochord
Neural plate and tube
Neural crest cells
Migration
www.indiandentalacademy.com
References
Contemporary OrthodonticsWilliam R Proffit
The Developing Human Moore and Persaud
Craniofacial Morphogenesis an...
Thank you
For more details please visit
www.indiandentalacademy.com

www.indiandentalacademy.com
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Neural crest cells 1 /certified fixed orthodontic courses by Indian dental academy

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Neural crest cells 1 /certified fixed orthodontic courses by Indian dental academy

  1. 1. Neural Crest Cells INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. “He who sees things grow from the beginning will have the finest view of them” -Aristotle www.indiandentalacademy.com
  3. 3. Fertilization It is sequence of events that begins with contact between a sperm and a oocyte and finally ends with the fusion of nuclei of the sperm and ovum and the intermingling of maternal and paternal chromosomes. Zygote www.indiandentalacademy.com
  4. 4. Cleavage It is a process by which zygote undergoes a series of rapid mitotic division. First the zygote divides into two cells known as Blastomeres www.indiandentalacademy.com
  5. 5. Zygote showing the process of cleavage www.indiandentalacademy.com
  6. 6. Time: The division starts 30 hours after fertilization. Site: This occurs as the zygote passes along the uterine tube towards the uterus. www.indiandentalacademy.com
  7. 7. www.indiandentalacademy.com
  8. 8. Important point: There is increase in the number of cell without an increase in the cytoplasmic mass as a result of which cells progressively become smaller in size. www.indiandentalacademy.com
  9. 9. Morula This is so called when the number of cells becomes 16 Time: 3-4 days after fertilizations Site: Uterus www.indiandentalacademy.com
  10. 10. Morula www.indiandentalacademy.com
  11. 11. BLASTOCYST Space appear between the central Blastomeres of Morula. This space gets filled with the fluid from the uterine cavity. Trophoblast Inner cell mass www.indiandentalacademy.com
  12. 12. Blastocyst www.indiandentalacademy.com
  13. 13. BLASTOCYST Following this fluid – filled spaces fuse to form a single, large blastocyst cavity. Blastocyst www.indiandentalacademy.com
  14. 14. Implantation Time: After six days The blastocyst attaches itself to the endometrial epithelium, adjacent t the inner cell mass Embryonic pole www.indiandentalacademy.com
  15. 15. Implantation As this occurs the trophoblast start proliferating rapidly cytotrophoblast syncytiotrophoblast www.indiandentalacademy.com
  16. 16. Implantation of the blastocyst www.indiandentalacademy.com
  17. 17. Implantation Finger like processes of syncytiotrophoblast extend through the endometrial epithelium Time:by the end of the first week blastocyst superficially implants in the endometrium. Also a flattened layer of cells called hypoblast appear on the surface of the inner cell mass. www.indiandentalacademy.com
  18. 18. Completion of implantation Time: the process of implantation is completed by the end of second week. As the blastocyst slowly embeds itself in the endometrium trophoblast goes on differentiating into the two cell layer. www.indiandentalacademy.com
  19. 19. Formation of the amniotic cavity As the implantation is progressing small cavity appears at the embryonic pole between embryoblast and trophoblast. This space forms the primodium of the amniotic cavity. www.indiandentalacademy.com
  20. 20. Developing amniotic cavity www.indiandentalacademy.com
  21. 21. Formation of Bilaminar plate At the same time morphologic changes occur in the embryoblast resulting in the formation of circular,bilaminar plate of the cells called embryonic disc epiblast hypoblast www.indiandentalacademy.com
  22. 22. Bilaminar plate www.indiandentalacademy.com
  23. 23. Formation of the primary yolk sac Few cells from the hypoblast migrate to form a membrane called exocoelomic membrane This membrane surrounds the blastocyst cavity called exocoelomic cavity. Primary yolk cell www.indiandentalacademy.com
  24. 24. Primary yolk sac www.indiandentalacademy.com
  25. 25. Formation of the secondary yolk cell Some cells from the hypoblast gives rise to a layer of loosely arranged tissue called-extra embryonic mesoderm. Extra embryonic coelom yolk sac www.indiandentalacademy.com
  26. 26. Development of the secondary yolk sac www.indiandentalacademy.com
  27. 27. Development of chorionic sac Extra embryonic coelom splits the extra embryonic mesoderm into two layers Extraembryonic Somatic mesoderm Extraembryonic Splanchic mesoderm www.indiandentalacademy.com
  28. 28. Development of chorionic sac Extra embryonic Somatic mesoderm + Two layers of trophoblast Chorion www.indiandentalacademy.com
  29. 29. Chorionic sac www.indiandentalacademy.com
  30. 30. Prochodral plate Time:around the 14th day few hypoblastic cells change into columnar shape and form a thickened ,circular area Prochodral plate . www.indiandentalacademy.com
  31. 31. Prochodral plate www.indiandentalacademy.com
  32. 32. The third week Gastrulation. Primitive streak. The notochordal process. Notochord. Neuralation. The neural crest cells. www.indiandentalacademy.com
  33. 33. Gastrulation It is process by which the bilaminar embryonic disc is converted into a trilaminar embryonic disc resulting in the formation of the three germ layers and the primitive streak. www.indiandentalacademy.com
  34. 34. Primitive streak It is a thickened linear band of epiblast which appears caudally in the median plane and on the dorsal aspect of the embryonic disc. Primitive node Primitive pit www.indiandentalacademy.com
  35. 35. Primitive node www.indiandentalacademy.com
  36. 36. Germ layers Mesoblast/Mesenchyme--mesoderm Primitive streak cell displace hypoblast -- endoderm Epiblast -- ectoderm www.indiandentalacademy.com
  37. 37. Developing germ layers www.indiandentalacademy.com
  38. 38. Notochordal process Some mesenchymal cells migrate cranially from the primitive node to form a median cellular cord known as notochordal process notochordal canal www.indiandentalacademy.com
  39. 39. The notochordal process prochordal plate Notochordal canal cloacal membrane www.indiandentalacademy.com
  40. 40. Formation of the notochord It is a cellular rod that develops by transformation of notochordal process - defines the primitive axis of embryo - gives rigidity - future site of vertebral column. www.indiandentalacademy.com
  41. 41. Formation of the notochord 1. As notochordal process elongates ,notochordal canal extends cranially from primitive node to prochordal plate . 2. Floor of the notochordal process fuses with the underlying embryonic endoderm. 3. Fused region gradually undergo degeneration creating an opening. www.indiandentalacademy.com
  42. 42. Developing notochord www.indiandentalacademy.com
  43. 43. Formation of the notochord 4. The opening rapidly becomes confluent and notochordal canal disappears . 5. Beginning at cranial end ,notochordal plate infolds to form notochord. 6. The notochord finally detached from the embryonic endoderm. www.indiandentalacademy.com
  44. 44. www.indiandentalacademy.com
  45. 45. Neuralation It is process involved in the formation of the neural plate and neural folds and the closure of these folds to form the neural tube. Neurla www.indiandentalacademy.com
  46. 46. Neural plate As the notochord develops ,embryonic ectoderm over it thickens to form the neural plate-neuroectoderm. Around the 18th day Neural tube www.indiandentalacademy.com
  47. 47. www.indiandentalacademy.com
  48. 48. The neural crest Some neuroectodermal cells lying along the crest of each neural fold lose their epithelial affinities and are called neural crest cells. These form a irregular flattened mass called neural crest . www.indiandentalacademy.com
  49. 49. www.indiandentalacademy.com
  50. 50. www.indiandentalacademy.com
  51. 51. Characteristics of the neural crest cells I. II. Pleuripotent capability –is the ability of these cells to give rise to several precursor cell. Migratory property-Ncc break free from neural folds by losing their lateral connections to adjacent epidermal and neuroectodermal cells. www.indiandentalacademy.com
  52. 52. Characteristics of the neural crest cells Migration Active Passive Without the ectoderm With the ectoderm www.indiandentalacademy.com
  53. 53. Factors affecting migration 1. Extra cellular molecules- such as fibronectin are encountered along the way of migration are used by Ncc to govern their path(Rovasio et.al.1983). 2. Vitamin A –slows the migration - acts as a teratogen www.indiandentalacademy.com
  54. 54. Factors affecting migration 3) Drugs-isotretenion(13-cis-retinoic acid)cause sever malformations by affecting the neural crest cell migration. www.indiandentalacademy.com
  55. 55. Characteristics of the neural crest cells III. Regulation- reffers to the ability of an embryo to compensate for the loss of cells . migration of the Ncc across the midline. - by increase proliferation of the remaining Ncc. www.indiandentalacademy.com
  56. 56. Study done by BonnerFraser(1986) CSAT antibody was used Antibody was injected in embryonic chicks just before the initiation of the Ncc migration. Results were observed after-24 hrs -36-48 hrs www.indiandentalacademy.com
  57. 57. Study done by BonnerFraser(1986) 24 hrs later-defective proliferation. defective initiation of migration. defective directionality of migration 36-48 hrs- Ncc developed normally www.indiandentalacademy.com -
  58. 58. Characteristics of the neural crest cells IV. Cessation-reffers to the property of the Ncc to cease the process of migration once they reach the site of future craniofacial structure. -type II collagen. www.indiandentalacademy.com
  59. 59. Structure derived by the neural crest cells I. Connective tissue- Ectomesenchyme of facial prominences and brachial arches. - Bones and cartilages of facial visceral skeleton. - Dermis of face and neck - Stroma of salivary ,thymus ,thyroid, parathyroid and pituitary gland. - Corneal mesenchyme . - Aortic arch arteries. www.indiandentalacademy.com
  60. 60. Structure derived by the neural crest cells II. -Dental papilla -Portions of periodontal ligament -Cementum Muscle tissue-Ciliary muscles -Covering connective tissue of branchial arch muscles www.indiandentalacademy.com
  61. 61. Structure derived by the neural crest cells III. Nervous tissue- -Leptomeninges. -Schwan sheath cells. IV. Sensory ganglia-Autonomic ganglia. -Spinal dorsal root ganglia. -Sensory ganglia. V. ANS-Sympathetic ganglia. -Parasympathetic ganglia. www.indiandentalacademy.com
  62. 62. Structure derived by the neural crest cells VI. Endocrine tissue- -Adrenomedullary cells -Calcitonin ‘c’ cells -Carotid body VII. Pigment cells-Melanocytes -Melanophores www.indiandentalacademy.com
  63. 63. Dental context 1. The initiation of the tooth formation. 2. The determination of the tooth's crown 3. 4. 5. 6. pattern. The initiation of dentinogenesis. The initiation of amelogenesis. The determination of the size,shape and number of the tooth roots. The determination of the anatomy of the dentogingival junction. www.indiandentalacademy.com
  64. 64. Clinical implications 1. Treachers Collins syndrome. 2. Hemifacial Microsomia. 3. Limb abnormalities. www.indiandentalacademy.com
  65. 65. Treachers Collins Syndrome www.indiandentalacademy.com
  66. 66. Hemifacial Microsomia www.indiandentalacademy.com
  67. 67. Summary of events Zygote Morula Blastula Implantation Amniotic cavity www.indiandentalacademy.com
  68. 68. Summary of events Bilaminar embryonic disc Yolk sac Chorionic sac Germ layers Primitive streak www.indiandentalacademy.com
  69. 69. Summary of events Notochord Neural plate and tube Neural crest cells Migration www.indiandentalacademy.com
  70. 70. References Contemporary OrthodonticsWilliam R Proffit The Developing Human Moore and Persaud Craniofacial Morphogenesis and DysmorphogenesisKatherine and Alphonse Craniofacial EmbryologyG.H.Sperber Oral histologyTencate www.indiandentalacademy.com
  71. 71. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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