Fetal lung and breathing

Fetal Respiratory Development

By Dylanr11

  • Pregnancy Term Begins

  • Period: to

    Pregnancy Term

  • Week 4: Embryonic Stage Begins

    Week 4: Embryonic Stage Begins

    Endoderm, Mesoderm, and Intraembryonic Coelom take place
    Lung buds sprout as a growth from the ventral wall of the foregut, also where lobar division takes place
  • Week 5: Embryonic Stage Ends, Pseudoglandular Stage Begins

    Week 5: Embryonic Stage Ends, Pseudoglandular Stage Begins

    Tubular branching continues, all segmental bronchi become present, stage is critical for formation of conducting airways
    epithelial tubes surrounded by mesenchyme are formed
  • Week 16: Canalicular Stage Begins

    Week 16: Canalicular Stage Begins

    bronchioles produced, capillaries in contact with cuboidal epithelium increase, alveolar epithelium begins to develop, future gas exchange regions can be identified

  • Week 17: Pseudoglandular Stage Ends

  • Week 24: Saccular Stage Begins

    Week 24: Saccular Stage Begins

    air sacs and alveolar ducts become developed, vascular tree grows, gas exchange region expands, fibroblastic cells produce extracellular matrix, collagen and elastin, saccules form

  • Week 25: Canalicular Stage Ends

  • Week 35: Alveolar Stage Begins

    Week 35: Alveolar Stage Begins

    number and size of capillaries and alveoli increase, amniotic fluid and respiratory motions aid in lung maturation, microvascular maturation occurs

  • Week 40: Saccular Stage Ends

  • 8 years Later: Alveolar Stage Ends

    8 years Later: Alveolar Stage Ends

    Lung and Respiratory System fully developed