Download Implantation

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
Why?
• Pregnancy  dentocraniofacial development
• Early diagnosis  clinical decision making, avoid
harmful treatment
• Future :
– fetus in utero + potential patient
– Biomedik : stem cell engineering
Contoh (populer)
cranio/orofacial malformation:
• Cleft lip/palate
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
Ruang
lingkup
– Production of egg and sperm
 gametogenesis
1st week
– Transport gametes and fertilization
development
– Cleavage and Embryo transport
– implantation
– Formation of germ layers
Embryonic
– Establishment of the Basic Embryonic stage
(2 to 2)
Body Plan
– Production of egg and sperm
 gametogenesis
–Transport gametes & fertilization
– Cleavage and Embryo transport
– implantation
– Formation of germ layers
– Establishment of the Basic Embryonic Body Plan
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.
Transport of Gametes and Fertilization (Contd..)
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
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
sperma vs ovum
The phase :
(1) Sperm penetration of corona
radiata
(2) Sperm binding and penetration of the
zona pellucida
(3) one sperm enters the egg  Fuse
 zygote
Acrosome reaction :
• Occurs after binding zona pellucida(zp)
• Release of enzymes (acrosin & trypsin like
substance ) needed to penetrate zp.
zygote
embryoblast
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.
– Production of egg and sperm
 gametogenesis
– Transport gametes & fertilization
–Cleavage and Embryo transport
– implantation
– Formation of germ layers
– Establishment of the Basic Embryonic Body Plan
Inner cell mass = embryo
Outer cell mass = trophoblast
Pre-embyonic
developmental
stages
Cleavage
=== a series of mitotic division that
result in increase in cells, blastomere,
which become smaller with each
division
• Fertilization zygote  2 cell stage
mitotic divisionnumber of cells
Blastomeres
Cleavage
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
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 & fertilization
– Cleavage and Embryo transport
–implantation
– Formation of germ layers
– Establishment of the Basic Embryonic Body Plan
embryoblast
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.
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)
Implantation
• Processes : zona pellucide disappear → polar
trophoblast touch the endometrium→secrete
proteolytase →dissolve the endometrium →
embedded into endometrium→coagulation plug
seal the space
• Day 8
– The blastocyst embeded partially in endometrium
– Trophoblast has differentiated into 2 layer :
• Inner layer of mononucleated cellCytotrophoblast
• 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]
 Month 3 to birth [fetus] :
• 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]
• lacunar stage
• Primary yolk sac
• Blastocyst is completely embedded
in the endometrial stroma
• uteroplacental circulation.
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]
– Production of egg and sperm
 gametogenesis
– Transport gametes & fertilization
– Cleavage and Embryo transport
– implantation
–Formation of germ layers
– Establishment of the Basic Embryonic Body Plan
Formation of Trilaminar Germ Disc
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
[ Third week of development]
Formation of Trilaminar Germ Disc
Trilaminar germ disc
= endoderm + mesoderm + ectoderm
determination 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
• 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
* : by mesodermal cells
• The notochordal process immediately rostral to the
primitive node and streak
• Mesenchymal cells from the primitive streak and
notochordal process migrate laterally and cranially ,
among other mesodermal cells, between the
ectoderm and endoderm until they reach the margins
of the embryonic disc.
• blood islands of the umbilical vesicle (yolk sac),
allantois, and chorion  intraembryo
3rd to eight week
Differentiation of trilaminar germ disc: 3th –
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
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
organogenesis
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
embryonic
organogenesis
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
reproductive gland
– nephrotome: segmentation
– nephrogenic cord:
and
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
Recaps
Recaps
Fourth Week
- Major changes in body form
- Early brain development ( till closing neuropore)
- limb buds
- otic pits
- lens placodes
- fourth pair of pharyngeal arches
fifth week
- growth of the head
- rapid development of the brain and facial prominences
A teratogen is any infectious agent, drug, chemical, or
irradiation that alters fetal morphology or fetal function if the fetus is
exposed during a critical stage of development.
1. The resistant period (week 1 of development)  the “all-ornone” phenomenon (i.e., the conceptus will either die as a result
of the teratogen or survive unaffected).
2. The maximum susceptibility period (weeks 3–8; 18 to 60 days
postconception = embryonic period). All organ morphogenesis
occurs at this time. Teratogenic exposures may result in
structural anomalies.
3. The lowered susceptibility period (weeks 9–38; fetal period)
All organs systems have already formed;
Teratogen exposure at this period generally results in a
functional derangement of an organ system. may result in
structural anomalies.
• Day by day of the conceptus

Week 2, days 8 – 14

Week 3 -8 [embryonic periode]

Month 3 to birth [fetus] :
• The Placenta and Fetal Membranes
The Placenta
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
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
• CNC : the major source of connective tissue
components, including cartilage, bone, and
ligaments in the facial and oral regions.
• myoblasts, originating from paraxial and
prechordal mesoderm, contribute to the
craniofacial voluntary muscles.
• The lower jaw and lower lip are the first
parts of the face to form. They result from
merging of the medial ends of the
mandibular prominences in the median
plane (will be discussed later……)
face
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.
• tdd : lateral plate mesoderm + ekstensi lateral dari
pharyngeal endoderm + CNC migration + ectoderm
• Inti : jar.mesenchymal, diselubungi ectoderm di
permukaan, dan lap.dalam dilapisi epithelia derivat
endoderm
• @ : 4th week
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
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