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CRANIOFACIAL DEVELOPMENT PRENATAL
dr.Indriati Dwi R, M.Kes Dep. Anatomi-Histologi
FKUB
We cannot teach people anything; we can only help them discover it within themselves.
Galileo Galilei
– Production of egg and sperm
gametogenesis
– Transport gametes and fertilization
– Cleavage and Embryo transport
– implantation
– Formation of germ layers
– Establishment of the Basic Embryonic Body Plan
Embryonic stage (2 to 2)
1st week development
Why?
• Pregnancy dentocraniofacial development
• Early diagnosis clinical decision making
• Future : fetus in utero + potential patient
Contoh (populer) cranio/orofacial malformation:
• Cleft lip/palate
Transport of Gametes and Fertilization
• Ovulation :
– Mid point of menstrual cycle
– Under the influence LH and
FSH floats out of the ovary
• Oocyte transport
Before ovulation, fimbriae of the oviduct sweep over the ovary, and tube contract rhytmically. Oocyte is carried into the tube by motion of cilia on the epithelial lining.
Sperm transport
• Seminiferous tubules epididymis, biochem (environment condusive to independent motion)
• reflex ejaculation of semen (emission & ejaculation)
• Capasitation : A period conditioning in the female reprod tract.
Transport of Gametes and Fertilization Contd..
Fertilization :
• the process by which male and
female gametes fuse
• Occurs in the ampullary region of the oviduct
Transport of Gametes and Fertilization Contd..
VIABILITY OF GAMETES
• the oocyte cannot be fertilized after 24 hours and that it degenerates shortly thereafter .
• Most human sperms probably do not survive for more than 48 hours in the female genital tract
• Fertilization
• Development Before Birth
• Development of Male and Female Sex
• Birth
• Development After Birth
Fertilization
sperma vs ovum
(1)Sperm penetration of corona radiata
(2) Sperm binding and penetration of the
zona pellucida
(3) one sperm enters the egg Fuse zygote
The phase :
Acrosome reaction :
• Occurs after binding zona pellucida(zp)
• Release of enzymes (acrosin & trypsin like substance ) needed to penetrate zp.
Approximately 6 days after fertilization, the cell mass is termed a blastocyst. Human chorionic gonadotropin now is produced in amounts that may be detected by commercial laboratories.
zygote
embryoblast
• Fertilization
• Development Before Birth
• Development of Male and Female Sex
• Birth
• Development After Birth
Birth defects
Birth defects can be classified based on :
• severity, medical or social consequences,
• pathogenetic mechanism
• their clinical presentation
Classification based on severity
• Major anomalies: these are birth defects that have medical or social consequences for the affected child. Ex : cleft lip and palate, atrial septal defect, & radial aplasia
• Minor anomalies: birth defects that have no significant health or social implications for the affected child. Ex : partial syndactyly of the second and third toes. Multiple minor anomalies can provide clues to the diagnosis of multiple congenital anomaly syndromes and they may also be a marker for a chromosomal aberration
• Common variants : end of the spectrum of normal development rather than birth defects. Ex : fetal finger pads, sacral dimple
Classification based on pathogenesis
• Deformation : aberrant mechanical force distorting normally developing structures
• Disruption : destructive processes that alter a structure after it has formed normally
• Malformation : failure or inadequate completion of normal developmental processes.
• Dysplasia : abnormal cellular organisation or function within a specific tissue type throughout the body
Classification based on clinical presentation
• Single-system defects. Ex : cleft lip and palate, talipes, pyloric stenosis and congenital heart disease.
• Multiple-system defects. – Syndrome : consistently occur together
– Association : non-random fashion, have no common specific aetiology
– Sequence :
– Complex
• Fertilization
• Development Before Birth
• Development of Male and Female Sex
• Birth
• Development After Birth
Inner cell mass = embryo Outer cell mass = trophoblast
Pre-embyonic developmental stages
Cleavage
• Fertilization zygote 2 cell stage mitotic
divisionnumber of cells
Blastomeres
Cleavage is a series of mitotic division that
result in increase in cells, blastomere,
which become smaller with each division
Blastocyst Formation :
• At the time morula enter the uterine cavity,
fluids penetrate through zona pellucida into
intercellular spaces of inner cell mass(icm).
Single cavity (blastocele)
• Embryo =blastocyst
• Inner cell mass = embryo
• Outer cell mass = trophoblast
Cleavage
• Early pregnancy factor, an
immunosuppressant protein, is secreted by
the trophoblastic cells and appears in the
maternal serum within 24 to 48 hours after
fertilization
Heading to
Implantation
• Zona pellucida is covering the embryo until its reach uterus preparation for implantation
• Four to 5 days after fertilization, the zona pellucida is shed and the trophoblast adjacent to the embryoblast attaches to the endometrial epithelium.
Production of egg and sperm gametogenesis
Transport gametes and fertilization
Cleavage and Embryo transport
implantation
Approximately 6 days after fertilization, the cell mass is termed a blastocyst. Human chorionic gonadotropin now is produced in amounts that may be detected by commercial laboratories.
embryoblast
Implantation • = kontak fisik & fisiologis pertama;
antara blastocyst vs mucosa uterus (6th -8th day),
• 3 phase : –Preparation of the uterus for adhesion and
implantation
– Trophoblast-uterus adhesion
–Blastocyst movement into the uterus (mid portion of the posterior/anterior)
• Processes : zona pellucide disappear → polar
trophoblast touch the endometrium→secrete
proteolytase →dissolve the endometrium →
embedded into endometrium→coagulation plug
seal the space
Implantation
• Day by day of the conceptus
Week 2, days 8 – 14
Week 3 -8 [embryonic periode]
Month 3 to birth [fetus] : OOT
• The Placenta and Fetal Membranes
• Day by day of the conceptus
Week 2, days 8 – 14 Week 3 -8 [embryonic periode]
Month 3 to birth [fetus] : OOT
• Day 8
– The blastocyst embeded partially in endometrium
– Trophoblast has differentiated into 2 layer :
• Inner layer of mononucleated cellCytotrophoblast
• Outer layer of multinucl Syncytiotrophoblast
– Embryoblast also differentiated into 2 layer :
• An upper layer of cuboidal cells epiblast
• A lower layer of collumnar cells hypoblast
Day by day of the conceptus
Week 2, days 8 – 14
Week 3 -8 [embryonic periode]
Formation of Germ Layers and Early Tissue and Organ Differentiation: Third Week
Organogenetic Period: Fourth to Eighth Weeks
Month 3 to birth [fetus] : OOT
Trilaminar germ disc= endoderm + mesoderm
+ ectodermdetermination of head and tail
of germ disc
• endoderm: hypoblast cells are replaced by
epiblast cells
• ectoderm: epiblast changed the name into
ectoderm
• mesoderm: intraembryonic mesoderm
Formation of Trilaminar Germ Disc
[ Third week of development]
Formation of mesoderm: early of 3 weeks Gastrulation :
– primitive streak: cells of epiblast proliferate to form a
longitudinal arranged cell cord
– primitive groove
– primitive node
– primitive pit
• Head process (The notochordal process gives an
appearance of being a prolongation of the primitive
streak in the direction of the future head region of the
embryo) →notochordal tube → notochord :
– buccopharyngeal membrane
– cloacal membrane
Formation of Trilaminar Germ Disc
• The notochordal process immdiately rostral to the primitive
node and streak
• blood islands of the umbilical vesicle
Differentiation of trilaminar germ disc: 4th –
8th weeks
• differentiation: same cells which are
primordial and immature differentiate into
different cells which have specific structure
and function
• induction: some tissues effect the
differentiation, and determine the
differentiating orientation of another tissue
Fourth to eight week
4 to 8 week of development (organogenesis)
• Differentiation of ectoderm: CNS
• Differentiation of mesoderm: dermis,
bone, cartilage, CT, muscles, pleura,
peritoneum and pericardium, cardiovascular
and lymph system
• Differentiation of endoderm: digestive,
respiratory and urinary system
CRANIOFACIAL DEVELOPMENT
inside
Differentiation of ectoderm: from 18th –19th days
• neural plate: neuro-epithelium(neural ectoderm):
pseudostratified columnar epithel.
• neural fold
• neural groove
• neural tube: →CNS
/anterior neuropore: closed by 25th days
/posterior neuropore: closed by 27th days
• neural crest(mesoectoderm): two lines of cell
cords→ganglion
organogenesis
embryonic
Differentiation of mesoderm: 17th days
• paraxial mesoderm
– somite: 20th days, 3 pairs/per day, 42-44 pairs by the
end of 5th weeks
– sclerotome: →bone, cartilage
– myotome: →skeletal muscle
– dermatome: dermis and hypodermis
• Intermediate mesoderm:→kidney and
reproductive gland
– nephrotome: segmentation
– nephrogenic cord:
organogenesis
• lateral mesoderm:
– intraembryonic coelom: →body cavity
– somatic or parietal mesoderm: →muscle, CT,
parietal layer of pleura, peritoneum and
pericardium
– splanchnic or visceral mesoderm: →muscle, CT
of digestive tract, visceral layer of pleura,
peritoneum and pericardium
– mesenchyme: →cardiovascular and lymph
system
organogenesis
Differentiation of endoderm:
• primitive gut: →digestive, respiratory and
urinary system
organogenesis
• Day by day of the conceptus
Week 2, days 8 – 14
Week 3 -8 [embryonic periode]
Month 3 to birth [fetus] : OOT
• The Placenta and Fetal Membranes
components:
• The fetal part : formed by the villous chorion.
The chorionic villi that arise from it project into the
intervillous space containing maternal blood.
• The maternal part : formed by the decidua basalis
By the end of the fourth month, the decidua basalis is almost
entirely replaced by the fetal part of the placenta.
The placenta and fetal membranes perform the following
functions and activities: protection, nutrition, respiration,
excretion, and hormone production
The Placenta
Morphogenesis Embyonic developmental stages 2 to 2
• Bagian dari proses tumbuh kembang embryo
Fokus pada :
Cranio (kepala) - facial (wajah) - dental (gigi)
- calvaria
head formation
apparatus pharyngeal
face
palata
Odontogenesis
Other : tongue , salivary gland , sense organ
Head formation
• Occurs at the earliest stages
• Orofacial from CNC (ectoderm origin)
• Calvaria from mesoderm (paraxial)
• Brain : ~ brain development
Neural crest PHARYNGEAL APPARATUS
Neural crest Paraxial mesoderm
Lateral plate mesoderm
neurocranium (shaded
area) and the
viscerocranium ( black area). The bones of the neurocranium and viscerocranium are derived almost entirely from neural crest cells, except for the basilar part of the occipital bone (asterisk), which forms from mesoderm of the occipital sclerotomes, and the laryngeal cartilages (asterisk), which form from mesoderm within pharyngeal arches 4 and 6.
OSSIFICATION of the SKULL Neurocranium (basis cranii) • Endochondral
– os.occipital, os.sphenoid, os.ethmoid
• Intramembranous – Calvaria
Viscerocranium From neural crest • Endochondral
– Maleus, incus, stapes, proc.styloid os temporal – Os hyoid
• Intramembranous – Os temporal, os maxilla, os zygomaticum – Os mandibula
At 12 weeks showing the cartilaginous base of the cranium or chondrocranium formed by the fusion of various cartilages. D, At 20 weeks indicating the derivation of the bones of the fetal cranium.
head formation
apparatus pharyngeal
face
palata
odontogenesis
Other : tongue , salivary gland , sense organ
Pharyngeal apparatus • Very dominat, typical feature in head&neck dev; esp.
lateral and ventral regions of the head and neck.
• 4th week, by the mesoderm lateral plate & lateral extensions of the pharyngeal endoderm + CNC migration
• From ectoderm-mesoderm-endoderm. (Incl. CNC)
• Inti : jar.mesenchymal, diselubungi ectoderm di permukaan, dan lap.dalam dilapisi epithelia derivat endoderm
Tdd : • Pharyngeal arches :
5* • Pahryngeal
pouches : 4* • Pharingeal
grooves/cleft : 4 • [Pharyngeal
membrane] : 4
Pharyngeal arches
Pharyngeal pouches
Pharingeal grooves/cleft
[Pharyngeal membrane]
End of part ONE