Dear Students,

Now that you know what is embryology, I encourage you to read from the recommended textbook.

Do not complain that the lecture contains only pictures.

Listen to the lecture carefully!!!!

Make your own notes by going through the books!!!

Understand the development of the the embryo

Formation of bilaminar germ disc

Abnormalities of implantation & trophoblasts

Blastocyst embedded

Trophoblast differentiates Cytotrophoblast Syncytiotrophoblast

Inner cell mass differentiates Hypoblast Epiblast

Formation of Amniotic cavity

Amnioblasts

Lacunar stage

Formation of Heuser’s membrane

Formation of exocoelomic cavity (Primitive yolk sac)

1. Hypoblast growing ventrally2. Eroded maternal capillaries3. Extraembryonic reticulum4. Heuser´s membrane5. Amniotic cavity6. Cytotrophoblast7. Syncytiotrophoblast8. Lacunae, filled with blood

Formation of

Sinusoids

Extraembryonic mesoderm

Extraembryonic coelom (Chorionic cavity)

Extraembryonic somatopleuric mesoderm

Extraembryonic splanchnopleuric mesoderm

Decidual reaction

Bleeding at implantation site

Formation of Primary villi

Definitive yolk sac

Exocoelomic cyst

Chorionic cavity

Chorionic plate

hCG – Syncytiotrophoblast

Used in Pregnancy test

LANGMAN’S MEDICAL EMBRYOLOGY – 11th edition

CHAPTER 4 – Second week of development Pgs. 47 – 54