Neural crest cell

NEURAL CREST CELL &
DEVELOPMENT OF SOFT
TISSUE OF FACE
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Embryogenesis is
divided into three
phases
• Pre implantation period
(first 7 days)
• Embryonic period (next 7
weeks)
• Fetal period (3 – 9 months)

Neural crest cellsNeural crest cells
Neural plateNeural plate
NotochordNotochord
Primitive streakPrimitive streak
Ectodermal cellsEctodermal cells
Germ layersGerm layers
MorulaMorula
zygotezygote

Embryology– first week

Second week
Bilaminar embryonic disc
Epiblast / ectoderm
2nd
germ layer
Embryo resembles disc
Epiblast / ectoderm
2nd
germ layer
Embryo resembles disc

Second week
Heusers membranewww.indiandentalacademy.com

Second week
• FORMATION OF PROCHORDAL PLATE
Bilaminar disc
Hypoblast cells- columnar
Indicates the future site of mouth
Cranial region of embryo
Bilaminar disc
Hypoblast cells- columnar
Indicates the future site of mouth
Cranial region of embryo

3rd
week
Rapid development
Primitive streak formation
3rd
germ layer formation
Notochord
Trilaminar embryo
Rapid development
Primitive streak formation
3rd
germ layer formation
Notochord
Trilaminar embryo

3rd
week
Prochordal plate
Head region
Hypoblast
Prochordal plate
Head region
Hypoblast
Primitive streak
Tail region
Epiblast
Primitive streak
Tail region
Epiblast

Formation of notochord
• Primitive streak
• Primitive knot
• Canalization of cord cells

Primitive streak and node

Migration of cells b/w
hypoblast and epiblast

3rd
week – Notochord
 Notochord is the structure around
which the vertebral column forms
 Developing notochord induces the
overlying ectoderm to form neural
plate

Neurulation
• End of 3 week
• Formation of neural tube and
neural plate

Formation of neural tube

Neurulation

Neural crest cells
• Ectomesenchymal in nature
• Major source of connective tissue
components, including cartilage,
bone and ligaments of facial and
oral region
• Contribute to muscles and arteries
of this region

• Ectomesenchymal tissue termed
neural crest cells appears in
the intermediate zone between
the surface ectoderm and the
neural tube during
neurulation.

Migraton is so excessive & their role is so imp
Considered as fourth primary germ layerwww.indiandentalacademy.com

Source and pattern of
migration to the developing
face and branchial arch system
As they migrate from rhombomeres ,carry with them homeobox gene
From the site.

Characteristics of neural
crest cells.
Pluripotent cells
Migration
Cyto-differentiation

Neural crest cells
DerivativesDerivatives
Connective tissue MusclesNervous tissues
Sensory ganglia
ANS
Pigment cells Endocrine tissues

Derivatives of neural
crest cells.
Connective tissue-
- Ectomesenchyme of facial
prominences and
branchial arches
- Bones and cartilages of facial
visceral skeleton

annotated_embryo.mov

-Dermis of face and neck
-Stroma of salivary ,thymus
thyroid,parathyroid and
pituitary gland
-Corneal mesenchyme
-Aortic arch arteries

-Dental papilla
-Portions of periodontal
ligament ,Cementum
Muscle tissue-
-Ciliary muscles
-Covering connective tissue of
branchial arch muscles

Nervous tissue-
-Leptomeninges.
-Schwann sheath cells

Endocrine tissues
• Adrenomedullary cells
• carotid body

Pigment cells
• Melanocytes in all tissues
• Melanophores of iris

Sensory ganglia-
-Autonomic ganglia.
-Spinal dorsal root ganglia.
-Sensory ganglia.
ANS-
-Sympathetic ganglia.
-Parasympathetic ganglia.

Factors affecting
migration
• Extra cellular molecules: like
fibronectin
• Vitamin A,isotretinoin
• 13 cis-retinoic acid
• Mutant geneswww.indiandentalacademy.com

Factors effecting the
normal growth of neural
crest derivatives
• Number of cells leaving the
neural tube
• Rate of migration
• Proportion of dividing
• Minimal period between
successive divisions
• Number of cells that die

Characteristics of neural
crest cells
• Regulation

Significance of neural
crest cells
• In craniofacial region
Differentiate to form most of
the connective tissue of head -
ectomesenchyme

Significance in
development of dentition
• Neural crest is primary
material for odontogenesis.
• Interaction between neural
crest, pharyngeal endoderm and
oral ectoderm produces the
dental lamina.
• Neural crest provides material
for dentin, pulp and cementum.www.indiandentalacademy.com

Altered Neural Crest
Development
• Mandibulofacial Dysostosis

• Hemifacial Microsomia

•Fetal alcohol syndrome
• Due to deficiences of midline
tissues of the neural plate
,caused by very high level of
ethanol.

Branchial arches or
pharyngeal arches

Each pair of branchial arches
contain a basic set of
structure
• Cartilage component
• Muscular component
• Vascular component
• Nervous component

Branchial arches
• Develops due to neural crest
migration in the 4th
week
• Mesenchyme of each branchial arch
gives rise to muscles, cartilages
and bone

First branchial arch
(mandibular arch)

1st
branchial arch
MANDIBULAR ARCHMANDIBULAR ARCH
MusclesMuscles
Skeletal structuresSkeletal structures
LigamentsLigamentsCartilageCartilage
NerveNerve

COMPONENTS OF 1st ARCH
• Cartilage : MECKEL’S CARTILAGE
--Arises 41st – 45th Day I.U
--It provides a template for
subsequent development of the
mandible.

Structures formed by
cartilaginous component

Nerve supply

2nd
branchial arch
HYOID ARCHHYOID ARCH
MusclesMuscles
Skeletal structuresSkeletal structures
LigamentsLigamentsCartilageCartilage
NerveNerve

Second branchial arch
(Hyoid Arch)
Components:
• Cartilage : Reichert’s Cartilage
(45th – 48th I.U)
-- Stapes
-- Styloid process of the
temporal bone.
_ _Stylohyoid ligament.
-- Lessor horn of sphenoid.
-- Cranial part - Body of
Hyoid.

• Muscles :
-- Stapedius
-- Stylohyoid
-- Post. Belly of
Digastric
-- auricular
-- muscles of
facial expression
.

• Nerve :
-- Facial / VII Cranial
nerve.
-- Chorda tympani nerve
(Ant 2/3rd of Tongue)
Artery :
-- Stapedial artery
-- Transient i.e. disappears
during fetal life

3rd
branchial arch
3rd
Arch3rd
Arch
9th
CN9th
CN StylopharyngeousStylopharyngeous
Greater cornu of hyoid
Lower part of body of hyoid
Greater cornu of hyoid
Lower part of body of hyoid

4th
& 6th
branchial arch
4TH
& 6TH
Arch4TH
& 6TH
Arch
Sup. Laryngeal N
Rec. Laryngeal N
Sup. Laryngeal N
Rec. Laryngeal N
Thyroid
Cricoid
Arytenoid
Corniculate
Cunieform
Thyroid
Cricoid
Arytenoid
Corniculate
Cunieform
cricothyroid
constrictors of pharynx
Laryngeal muscles
cricothyroid
constrictors of pharynx
Laryngeal muscles

Ectodermal clefts
Epi. Lining of ext. acoustic meatus
Auricle
Epi. Lining of ext. acoustic meatus
Auricle

Ectodermal clefts
Branchial cystBranchial cyst Branchial sinusBranchial sinus

Endodermal pouches

Branchial arch malformations
• Branchial cyst
• Branchial sinus
• Branchial fistula

Thanx

Development of Tongue

Tongue

Tongue
Papillae and taste buds
• End of 8th
week – vallate & foliate( 9th
CN)????
Relation to terminal branches OF 9th
CN

Tongue
• Fungiform papillae – develop near termination of chorda
tympani
Filiform
• Appear in early fetal life
• No taste buds
• Sensitive to touch

Tongue
Nerve supply
Lingual N
Chorda tympani
Lingual N
Chorda tympani
Glossopharyngeal NGlossopharyngeal N
Vagus NVagus N

Tongue
Important points
• 2nd
branchial arch does not contribute to tongue formation
Chorda tympani supplies fungiform papillae????

Tongue
Lymphatic drainageLymphatic drainage

Clinical
correlation
• Tongue tie
• Macroglossia
• Microglossia
• Bifid tongue
• Fissured tongue
• Rhomboid tongue

Malformations of tongue
AnkyloglossiaAnkyloglossia

Fissured tongueFissured tongue

Bifid tongueBifid tongue

Median rhomboid glossitisMedian rhomboid glossitis

MacroglossiaMacroglossia

Hypertrophy of papillaeHypertrophy of papillae

Development of the
face

• Face is derived from the
following structures that lie
around the stomatodaeum:
• Frontonasal process
• First pharyngeal arch

Facial prominences

Upper lip
maxillary process with medial &
lateral nasal process
Frontonasal process becomes narrow
Lower lip and jaw
Mand. Prominences

Nose
medial & lateral nasal
process (rt & lt)
Eye
lens placode

• Dev. Of the face starts at
the end of 4 week

Facial Malformations

References
• The Developing Human - Keith L Moore
• Craniofacial Embryology -
G.H.Sperber
• Human Embryology - I.B.Singh
• Color Atlas of Oral Path - Robinson,
Miller

Thank you
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Neural crest cell

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