Bio med craniofacial and tooth development

NCC from r4

migrate to arch 2 (hyoid)

NCC from r6, r7, r8

migrate into arch 3, 4, and 6

ectodermal cells overlying the notochord

start to thicken and form the neural plate and these cells make neuroectoderm and soon from nervous system and Neural crest cells (ectomesenchyme cells)

Cephalic cardiac NCC

contribute to the outflow of the heart

trunk thoracic neural crest cells

form peripheral nervous system

parts of the trunk thoracic NCC

spinal ganglia, ganglia and satellite cells (schwann cells)melanocytesadrenal medullaneurosecretory cells of heat and legs

trunk sacral NCC

migrate later in development of posterior gut

form parasympathetic ganglia

trunk sacral NCC

cranial neural crest structures

connective tissue

Meckel's cartilage

TMJ

cranial bone

dentine

brachial (pharyngeal) arches give rise too

cranial nerve, cartilage, blood vessels, muscles (branchiomeric)

what is mesenchyme made of

mesoderm + NCC derived mesenchyme

Trunk NCC parts of nervous system (sensory)

spinal ganglia

Cephalic NCC parts of nervous system

Ganglia of:

trigeminal (V)

Facial (VII)

glossopharyngeal (IX)

vagus (X)

trunk NCC part of autonomic nervous system

ganglia, satellite cells (schwann cells)

Cephalic NCC parts of autonomic nervous system

ganglia (para) satellite cells (schwann cells)

Trunk and Cephalic pigment cells

made of melanocytes

Trunk NCC Endocrinal parts

adrenal medulla, neurosecretory cells of heart and lungs

Cephalic NCC endocrinal parts

carotid body, thyroid, parafollicular cells, stroma of salivary glands

when do the pharyngeal arches form

around 4th week of embryonic development

what are pharyngeal arches made of

lined externally by ectoderm, internally my endoderm and filled with mesenchyme

where do pharyngeal arches appear

on ventrolateral surface of the embryos head

Neurocristopathies

defects in neural crest migration

cranial neurocristopathies

cleft lip/palate

teacher collins syndrome

DiGeorge syndrome

Frontal nasal dysplasia

Trunk Neurocristopathies

Hirschsprung disease

Hirschsprung disease

parasympathic ganglion cells in wall of large intestine don't develop before birth

Stomodeum

primitive mouth (shallow depression in embryonic surface ectoderm at cephalic end)

Stomodeum and oral cavity formation

oropharyngeal membrane separates stomodeum from primitive pharynx

primitive pharynx

The cranial part of the foregut - the beginning of the future digestive tract

first event in development of face (4weeks)

disinigration of oropharyngeal membrane

occurs with growth of pharyngeal arches and formation of facial placodes

disinigration of oropharyngeal membrane (1st development)

Brachial (pharyngeal arches)

homologous to gill arches in somatic period (4-5weeks)

series of mesenchymal swelling

brachial arches

has surface made of ectoderm with neural crest derived mesenchymal cores

brachial arches

groove

space between 2 arches in ectoderm

pouch

space between arches on endoderm

Arch 1 (mandibular)

CN V (trigeminal)

Meckel's cartilage

maxillary artery

mastication muscle

parts of arch 1 with pouch as middle ear

malleolus, incus, and sphenomandibular ligament

pouch is the middle ear

arch 1

groove is external auditory meatus

arch 1 and 2

end feature of arch 1

temporalis, masseter, belly of digastric muscle

Arch 2 (hyoid)

CN VII (facial)

Reicherts's cartilage (hyoid lesser horn)

facial expression muscles

stapedial artery

pouch is the tonsils

arch 2

parts of arch 2

stapes, styloid process and lesser horn of hyoid

end features of arch 2

muscles of face, occipitalis, auricularis

arch 3

CN IX (glossopharyngeal)

greater horn of hyoid cartilage

stylopharyngeus muscle

internal common carotid artery

pouch is inferior parathyroid and thymus

arch 3

end features of arch 3

stylopharyngeus and body of hyoid

Arch 4 and 6

CN X (vagus)

laryngeal cartilage

pharyngeal and laryngeal muscle

aortic arch and right subclavian a. and ductus arteriosus

blood vessels of arch 4

aortic arch and subclavian artery

blood vessel of arch 6

ductus arteriosus

pouch is superior parathyroid and post brachial body (endocrine glands)

arch 4 & 6

groove of arch 4 and 6

cervical sinus

start of facial development (5-7w)

fusion of 5 facial prominences in arch 1

5 facial prominences

frontal nasal prominence2 medial nasal prominence2 maxillary prominences

process of fusion of facial prominences

epithelium between prominence disappear -> mesenchyme fuse -> end with smooth face

frontal prominence

develops in midline after closure of neuropores

maxillary region development (6-7w)

nasomedial processes and nose formation

nasomedial processes

fuse laterally with maxillary processes

merg across midline to form philtrum, tip of nose and most intermaxillary segment

nasomedial processes

nose formation

formed by 5 nasal prominences

prominences of nasal formation

frontonasal

2 nasomedial

2nasolateral

the area with the central upper incisors

appears from the frontonasal prominence

oronasal membrane degeneration

allows nose development

Meckel's cartilage

cartilaginous rod extending bilaterally from middle ear region to the tip of the future chin

where is the Meckels cartilage

in arch 1 (mandibular- it's part of mandible)

forms early in development around 4-5 weeks and last till 20 weeks

Meckel's cartilage

endochondral ossification sites

allow intermembranous ossification lateral to cartilage to then form mandible

secondary tissue

tissue capping the mandibular condyle

Mandibular condyle cartilage

derived from the periosteum of mandibular ramus

Palatal development

develops in 3 parts, primary palate and 2 parts of secondary palate

primary palate

forms from intermaxillary segments (nasomedial process)

contains premaxillary bones and has maxillary incisors

primary palate

secondary palate

made of 2 lateral palatine processes of maxilla (5-6w)

cleft lip/palate

failure of maxillary process to fuse with medial nasal process and probably the frontonasal prominence (inilateral)

most common craniofacial birth defect

cleft lip/palate (syndromic and non-ssyndromic)

differences in cleft palate

ethnic: asians (2:1000)

gender: female affected 2x as males

Main process of tooth development

initiation

morphogenesis

cytodifferentiation

matrix apposition

maturation

eruption

stages of crown formation

dental lamina (initiation)

Bud (proliferation)

Cap (proliferation, differentiation and morphogenesis)

bell (proliferation, differentiation and morphogenesis)

apposition (induction and proliferation)

maturation

dental lamina (stage 1)

forms from oral epithelium under neural crest induction and make Horeshoe shaped ridge in each jaw

the 10 locations on each horseshoe shaped ridges

early enamel organs

early enamel organs

formed by NCC induction of tooth buds by lamina

successional dental lamina

extension of dental lamina into ectomesenchyme forming succedaneous permanent teeth

when is dental lamina functional

6th prenatal week till 15yrs (3rd molar)

Bud stage (stage 2)

the formation of the early enamel organ being proliferated into buds

ectomesenchyme during bud stage

condenses around the bud

congenital absence of teeth due to interruption in what stage

bud stage 2

Cap stage (stage 3)

start of differentiation and morphogenesis

morpho differentiation

proliferation of bud cells to cap

Cytodifferentiation

in cap stage where enamel organ begins to form 4 distinct layer that will be fully formed in bell stage

surrounding mesenchyme during cap stage

dental papilla (dentin and pulp)

Dental sac (cementum, PDL and alveolar bone

formation of the tooth germ

in cap stage 3

what is tooth germ made of

enamel organ, dental papilla, dental sac

successional dental lamina in cap stage

form on lingual side of lamina

Enamel knot

signaling center controlling cusp development

cluster of nondivided epithelial cells

enamel knot

secondary knot

formed by regression of primary enamel knot (in molars)

bell stage (stage 4)

enamel organ is fully formed and dentinoenamel junction location is established

4 layers formed by enamel organ in bell stage

outer enamel epithelium (OEE)

Stellate reticulum (SR)

Stratum Intermedium (SI)

Inner enamel epithelium (IEE)

outer enamel epithelium (OEE)

Outer cuboidal cells of enamel organ; serves as protective barrier for enamel organ and blood supply (capillary plexus)

Stellate reticulum (SR)

star shaped cells that secrete GAG which allows water uptake to increase volume