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EMBRYOGENESIS OF ORO CRANIO FACIAL - Coggle Diagram
EMBRYOGENESIS OF ORO CRANIO FACIAL
THE FORMATION OF THREE EMBRYONIC LAYER
the mesoderm (middle layer) will form the notochord, axial skeleton, cartilage, connective tissue, trunk muscles, kidneys and blood
the endoderm (inner layer) goes on to form the gastrointestinal, respiratory and urinary systems as well as many endocrine glands
The ectoderm (outer layer) gives rise to the nervous system, epidermis and various neural crest-derived tissues
THE FACIAL GROWTH
Palate: These grow inferiorly from the primary palate until the end of the sixth week
Skull: Face bones (viscerocranium) are mostly neural crest mesenchyme. These bones originate through intramembranous or endochondral ossification of cartilage.
Face: Develops between the 5th and 10th week
THE ARCH THAT FORMED IN EMBRYONIC
Pharyngeal clefts (Pharyngeal lucus): Lie in between the pharyngeal arches outside the developing pharynx and are lined in ectoderm.
Pharyngeal pouches: infoldings lined with endoderm between the pharyngeal pouches on the inside of the pharynx
The pharyngeal arches: Appeared at the end of the fourth week and develop through into the fifth week
EMBRYONIC LAYER THAT FORMS THE HEAD AND NECK
Neural tube will form the primitive forebrain which produces a budge known as frontal prominence
The paraxial mesoderm will produce somitomers and somites
Neurulation: Responsible for the formation of the brain and spinal cord. Neurulation transforms the neural plate (forms from thickened ectoderm) into a neural tube. There are two major ways of forming neural tubes by primary and secondary neurulation.
Neural crest is the interaction of the neural plate and this is early development in ectoderm.
3 embryonic layers develop in 3 weeks, the human development involves in fusion of two embryological tissues, the neural crest and the neural plate
Neural crest cell from the midbrain will infiltrate the mesoderm because, they support the development of embryonic connective tissues
GROWTH AND DEVELOPMENT OF THE NOSE
Maxillary Bone Development
maxilla: above canine fossa of 6th week
ossifies in 3 primary centers: 1 for maxilla, 2 for premaxilla
Maxillary bone development:
fully intramembranous, within connective tissue
above incisive fossa, 7th week
PRE-MAXILLA
above incisive fossa, 7th week
paraseptal, 10th week
Mandibullary Bone Development: The two mandibular processes grow medially and fuse to form the lower lip and lower jaw
Meckel's Cartilage:
from the 1st pharyngeal arch
provides growth template for mandible
1st pharyngeal arch
maxillary proc. → Premaxillary, maxillary, zygomatic bone, and part of the temporal bone
mandibulary proc. → mandible
Ossification of Mandible
Intramembranous: body of mandible except anterior (ramus-mandibular foramen)
Endochondral: symphysis, ramus above mandibular foramen, coronoid, condylar proc.
THE GROW OF ORAL CAVITY
The oral cavity develop due to the deepening oral pit appeared between the forebrain and the heart
The oropharyngeal membrane is open the oral cavity to the tubular foregut in the fifth week and transforms into the oropharynx
During the fourth week of development, the neural plate bends ventarally as the neural folds create the forebrain, resulting in the initial appearance of the oral pit. The cephalacaudal bend pushes the heart ventrally and the yolk sac becomes enclosed to create an elongating tube known as the forugut (pharynx).
The mandibular arch will develop laterally.
The oropharynx is composed of the primitive oral cavity and the area called pharynx
The maxilla is located within the oral cavity and there are two maxillary bones that are fused at the intermaxillary suture during development. In the oral pit, the maxillary process produces cheeks and at the end of fourth week, the heart starts to enlarge and beat. It is positioned beneath the mandibular arch in the thorax.
THE DEVELOPMENT OF PALATE
On 7th-8th week, maxillary processes expand medially forming palatal shelves, secondary palate
End of 8th week: the two secondary palatal processes fuse and with the primary palate to form the definitive palate.
Intermaxillary segment has formed; Form 1/3 definitive palateand develop becomes philtrum, upper lip, and 4 incisors
TONGUE GROWTH
Adult tongue is differentiated into (they have different nerve supply
The 1/3rd posterior formed→ from 2nd, 3rd, 4th pharyngeal arches
separated by terminal sulcus
anterior 2/3rd → from 1st pharyngeal arch