L9 human embryology and developmental biology

8 important questions on L9 human embryology and developmental biology

When is the embryonic period?
And when the fatal period?

  • week 3-8 - embryonic
  • remaining 30 weeks - fetal

When is the prenatal period?
When is the pre-embryonic period?

  • The 38 weeks between fertilisation and birth
  • First 2 weeks development when zygote becomes spherical, multi-cellular structure.

What are the trimesters of pregnancy?

1st = week's 1-13
2nd = week's 14-26
3rd = week's 27 and on (38-40 weeks)
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart

How is the inner cell mass (ICM) also called in mammals? And what is it?

The inner cell mass also known as embryoblast in
mammals, is the mass of cells inside the primordial embryo that, once fertilized, will eventually give rise to the definitive structures of the foetus.

What does the last fase of gastrulation consist of?

1. Forming primitive streak
2. Chorda formation

Germlayer formation and movement during gastrulation

Endoderm -> formed from migrating cells that replace the hypoblast cells


Mesoderm (intraembryonic) -> formed between epiblast and endoderm

Ectoderm -> formed during epiblast cells that stay on dorsal surface

So, all layers derive from epiblast cells!!!

Formation of the body axes - Week 3

What is the primitive node?
From what is the notochord formed?

Primitive node = a swelling at one end of the primitive streak

Notochord -> is formed from primitive node and mesoderm.

  • defines body axis
    • is the site of the future vertebral column
    • appears on day 16


  • notochord also induces formation neuroectoderm and differentiation of motor neurons

What is differentiation?
And what is Induction?

Differentiation:
progenitor cells differentiate into various cells which have specific structure and function

Induction:
some tissues affect the differentiation, and determine the differentiating orientation of another tissue.

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo