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○ Prenatal development begins right after conception.
○ Formation of zygote.
○ Meiosis the joining of sperm's chromosome w/ ovums.
○ Congenital malformations occur during the preimplantation
period and embryonic period -
○ Congenital malformations occur during the preimplantation period and embryonic period ○ CV system begins to develop
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Week 3
○ Development of embryonic cell layers: Ectoderm, mesoderm, endoderm, and neural crest cells
○ (Three embryonic layers are: Ectoderm Mesoderm and endoderm).
○ Primordium
○ CNS formations:
□ A: Formation of neuroectoderm from the ectoderm
□ B: Formation of neural groove and neural fold.
□ C: Then these two meet and fuse and form neural forming neural tube.
○ Neural Crest Cells (NCCS)- Develop from neuroectoderm
□ Cells then migrate and then disperse within mesenchyme -
○ Trilaminar embryonic disc has folded into embryo
□ Development of the ectoderm and there is development
with the brain with spinal cord, heart, and digestive tract. -
○ The neck and face and its associated tissue begin to form.
○ Brain of the embryo bulges over the Orophayngeal membrane and developing heart.
○ Gestation- heart begins to beat and circulate blood
○ The area of the future face is squeezed between the developing brain and heart with the formation three embryonic layers and result and embryonic folding.
○ Embryonic Orofacial development begins
-Cervical development begins week 4
○ Tongue begins its development. (tuberculum impair) -
○ Formation of palate: primary
○ Intermaxillary segment forms then arises as a result of fusion
of the two medial nasal processes internally with the embryo.
○ Facial features are starting to develop
○ Eyes start to form
○ Blood begins to circulate -
○ Upper and lower lip formation- maxillary processes fuses with each nasal process by proliferation of the NCCs mesenchyme.
□ Contributes to side of lip and philtrum.
○ Bilateral maxillary processes give rise to two palatal shelves
□ Grow inferiorly and deep on the inside of the stomodeum.
○ The tongue is forming more
○ Secondary Palate formation begins
○ Future nasal septum is forming
○ Development of face is completed.
○ Lungs start to form
○ Fingers and toes start to form -
○ Secondary palate formation end w8
○ Tongue has completed fusion w8
○ Face begins to look more human like
○ External ears start to form -
○ Reproductive organs form
○ Tooth buds appear
○ Completion of fusion of final palate (w12)
○ End of Orofacial development (w12)
○ Taste buds develop (w11-13)
○ End of cervical development
○ Eyelids form
○ Fetus is active
○ Brain activity detected -
○ Brain develops rapidly
○ Alveoli form in the lungs
○ Eyebrows, eyelashes, and nails appear
○ Muscle develops
○ Feel kicking and movement -
○ Body fat increases
○ Bones complete development
○ Brain is always active.
○ Fetus is settling into pelvis
