II. Physiology: Day 1 - Conception
- Ovulation
- Fertilization
III. Physiology: Day 2-3 - Zygote develops into Morula
- Morula: round mass of cells
- Morula passes through fallopian tube
IV. Physiology: Day 4 - Morula develops into blastocyst
- Blastocyst: hollow sphere
- Inner Cell mass: mound on inner surface
- Primitive trophoblast: outer shell of sphere
- Together with mesoderm will form Chorion
- Blastocyst floats free in Uterus
VI. Physiology: Day 8 - Bilaminar Germ Disk develops
- Ectoderm (Epiblast) lines amniotic sac
- Skin and appendages
- Nervous system
- Adrenal Medulla
- Anterior pituitary
- Salivary Glands
- Mesoderm forms between Ectoderm and Entoderm
- Bone, Muscle, Cartilage, and connective tissue
- Serous linings
- Cardiovascular System
- Kidneys
- Genitalia
- Entoderm (Hypoblast) lines Yolk Sac
- Gastrointestinal Tract
- Liver
- Gall Bladder and biliary tract
- Pancreas
- Respiratory tract
- Gonadal germ cells
VII. Physiology: Day 9-13 - Placenta develops
- Trophoblast forms with lacunae
- Maternal and Trophoblast Vessels develop
- Uteroplacental circulation begins