Hematopoiesis (blood cell formation) begins.
Moore KL, Persaud TVN. 1998. The Developing Human: Clinically Oriented Embryology. 6th ed. Philadelphia: WB Saunders Co.
Collecting tubules, formed from metanephric diverticulum, undergo repeated branching, forming major and minor calices; the end of each tubule forms a metanephric vesicle.
Duration: 2 weeks
Moore KL, Persaud TVN. 1998. The Developing Human: Clinically Oriented Embryology. 6th ed. Philadelphia: WB Saunders Co.
Primary intestinal loop herniates into the umbilicus, rotating 90 degrees by week 8.
Duration: 2 weeks
Larsen WJ. 1997. Human Embryology. New York: Churchill Livingstone Inc.
Branching leads to the formation of terminal bronchioles by week 16.
Duration: 10 weeks
Larsen WJ. 1997. Human Embryology. New York: Churchill Livingstone Inc.