Prenatal Timeline

  • Jan 1, 1000

    Week 1 - The Preimplantation Period

    Week 1 - The Preimplantation Period
    -An ovum, an unfertilized female gamete, is released from the ovary and begins to travel down the fallopian tube.
    -A sperm cell meets the ovum and penetrates it, which fertilizes the cell and makes it an egg.
    -The nucleus of the sperm cell combines with the egg becoming a single cell or a zygote.
    -The zygote begins to divide into many cells while traveling down the fallopian tube, also known as mitosis. Once the division is complete the zygote is now known as a blastocyst.
  • Feb 2, 1000

    Week 3-8 Embryonic Stage

    Week 3-8 Embryonic Stage
    -Begins when blastocyst implants itself into uterine wall.
    -Formation of 3 cell layer*
    -Nervous system develops
    -Most organs begin to develop
  • Feb 3, 1000

    Week 2 (Day 8-9) - Implantation

    Week 2 (Day 8-9) - Implantation
    -Blastocyst makes it to the uterus and out of the fallopian tube.
    -Implants itself into the uterine wall lining
    -Implanted blastocyst grows by increased proliferation
    -Increased number of embryonic cells = emryonic cell layers
    -Bilaminar ebryonic disc has superior (epiblast) and inferior (hypoblast) layers
  • Feb 4, 1000

    Week 3 - Development of Embryonic Cell Layers

    -Primitive streak forms
    -Embryonic cell forms into three layers
    -Endoderm (inner layer)
    -develops into cells of most internal glands and organs
    - Mesoderm (middle layer)
    -develops into bones and muscle cells
    -Ectoderm (outer layer)
    -develops into skin and nerve cells
    -Neural tube formation and development of blood circulation begin
    -Cell now has cephalic (head) and caudal (tail) end
    -CNS begins to form
    -Neural groove begins to form and is protected by neural folds
  • Feb 5, 1000

    Week 4

    Week 4
    -Embryo undergoes emryonic folding
    -Face and neck begins to form
    -Eyes, nose, oral cavity (stodum), and jaw area is visible
    -two mandibular processes are forming
    -forms the mandibular arch
  • Week 5

    Week  5
    -Intermaxillary Segment forms
    -Gives rise to the primary palate
  • Week 8

    Week 8
    -Formation of tongue is complete
    -Extimesenchyme
  • Week 6-7

    Week 6-7
    -Bilateral maxillary gives rise to two palatal shelves forming the
    -Tongue begins to form on the floor of the primitive pharynx
    -Maxillary process fuses with medial nasal process
    -Dental Lamina (week 7)
  • Week 10 "Cap Stage"

    Week 10 "Cap Stage"
    -Tooth germ
    -Dental sac
    -morphogenesis
  • Week 11 "Bell Stage"

    -Outer and inner enamk epithelium forms
    -Stellate reticulum forms
    -Stratum untermedium forms
  • Week 12 "Bud stage"

    • All three processes fuse to form the final palate -odontoblast and dentin matrix