Neural crest cell /certified fixed orthodontic courses by Indian dental academy

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)


zygote
zygote
Morula
Morula
Germ layers
Germ layers
Ectodermal cells
Ectodermal cells
Primitive streak
Primitive streak
Notochord
Notochord
Neural plate
Neural plate
Neural crest cells
Neural crest cells

Embryology– first week


Second week

Epiblast // ectoderm
Epiblast ectoderm
2nd germ layer
2nd germ layer
Embryo resembles disc
Embryo resembles disc

Bilaminar embryonic disc

Second week

Heusers membrane


Second week
• FORMATION OF PROCHORDAL PLATE

Bilaminar disc
Bilaminar disc
Hypoblast cells- columnar
Hypoblast cells- columnar
Indicates the future site of mouth
Indicates the future site of mouth
Cranial region of embryo
Cranial region of embryo


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


3rd week

Prochordal plate
Prochordal plate
Head region
Head region
Hypoblast
Hypoblast

Primitive streak
Primitive streak
Tail region
Tail region
Epiblast
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 layer

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
Connective tissue

Muscles

Derivatives
Derivatives

Pigment cells

Nervous tissues

ANS

Sensory ganglia

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 genes

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.

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
Skeletal structures
Skeletal structures
Ligaments
Ligaments

Cartilage
Cartilage
MANDIBULAR ARCH
MANDIBULAR ARCH

Muscles
Muscles

Nerve
Nerve

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
Skeletal structures
Skeletal structures
Ligaments
Ligaments

Cartilage
Cartilage
HYOID ARCH
HYOID ARCH

Muscles
Muscles

Nerve
Nerve

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
Greater cornu of hyoid
Greater cornu of hyoid
Lower part of body of hyoid
Lower part of body of hyoid

3rd Arch
3rd Arch
9th CN
9th CN

Stylopharyngeous
Stylopharyngeous

4th & 6th branchial arch
Thyroid
Thyroid
Cricoid
Cricoid
Arytenoid
Arytenoid
Corniculate
Corniculate
Cunieform
Cunieform
4TH & 6TH Arch
4TH & 6TH Arch
Sup. Laryngeal N
Sup. Laryngeal N
Rec. Laryngeal N
Rec. Laryngeal N

cricothyroid
cricothyroid
constrictors of pharynx
constrictors of pharynx
Laryngeal muscles
Laryngeal muscles


Ectodermal clefts

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


Ectodermal clefts

Branchial cyst
Branchial cyst

Branchial sinus
Branchial 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
Vagus N
Vagus N
Glossopharyngeal N
Glossopharyngeal N
Lingual N
Lingual N
Chorda tympani
Chorda tympani

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


Tongue


Lymphatic drainage
Lymphatic drainage

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

Malformations of tongue
Ankyloglossia
Ankyloglossia


Fissured tongue
Fissured tongue



Bifid tongue
Bifid tongue


Median rhomboid glossitis
Median rhomboid glossitis


Macroglossia
Macroglossia


Hypertrophy of papillae
Hypertrophy 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 /certified fixed orthodontic courses by Indian dental academy

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