Embryology 101

Question 1

Embryogenesis

Answer 1

It’s the process of development from a single cell to the establishment of organ primordia. It happens in the first 8 weeks of human development.

Question 2

Fetal period

Answer 2

The process of development from the establishment of organ primordia to the birth.

Question 3

Zone of Polarizing Activity

Answer 3

It is the signaling center in the posterior margin of the developing limb that patterns the limb using signaling molecules (like the sonic hedgehog)

Question 4

Amelia

Answer 4

It’s an embryological abnormality that causes the limbs to be absent.

Question 5

Phocomelia

Answer 5

It’s an embryological abnormality that causes the lack of long limb bones, making only the hand or foot attached to the torso.

Question 6

Notochord

Answer 6

Rod of cells, supporting axis of the body for the lowest chordates and embryos of other chordates.

Question 7

Placode

Answer 7

Local thickening in the embryonic ectoderm layer that develops into a sensory organ or ganglion.

Question 8

What’s the difference between hetero and euchromatin?

Answer 8

Heterochromathin is tightly coiled and is not transcribed, while euchromathin is uncoiled and transcribed into proteins.