Embryology

Question 1

What week does gastrulation occur?

Answer 1

Week 3

Question 2

What is gastrulation?

Answer 2

Formation of trilaminar layer from the bilaminar layer

Question 3

What are the 3 germ layers and what do they differentiate in to?

Answer 3

Endoderm - lining of digestive tracts and respiratory tracts

Mesoderm - lining of body cavity and surround organs, muscles, connective tissue, bone, blood vessels

Ectoderm - nervous system, epidermis, enamel of teeth, glands, eye, ear, nose

Question 4

What week does organogenesis occur?

Answer 4

Week 3-8

Question 5

What does the mesoderm differentiate into?

Answer 5

Paraxial mesoderm - forms msk trunk
Intermediate mesoderm - forms urogenital system
Lateral mesoderm - forms msk limbs

Question 6

How is the axial skeleton formed?

Answer 6

Paraxial mesoderm exists as bilateral longitudinal columns either side of the neural tube.
By the end of third week, the columns divide into paired segments at each vertebrae level - somites, starting at the cranial region down to cauda

mesenchymal cells within somites - myotomes, dermatomes, sclerotomes

Question 7

How is the neural tube formed?

Answer 7

Notochord initiates neurulation, forming neural tube between ectoderm and mesoderm