Embryology

Question 1

What words are used to describe anatomical planes of a foetus?

Answer 1

Ventral (equivalent of anterior)
Dorsal (equivalent of posterior)
Cranial (equivalent of superior)
Caudal (equivalent of inferior)

Question 2

What primary processes are involved in development of a zygote?

Answer 2

Cell Division
Cell Attachment 
Induction
Cell Migration 
Apoptosis 
Cell Differentiation

Question 3

What are the stages of embryogenesis?

Answer 3

1. Gametogenesis
2. Fertilisation
3. Cleavage
4. Gastrulation
5. Formation of the Body Plan
6. Organogenesis
7. Foetal Period

Question 4

What secondary processes are involved in zygote development?

Answer 4

Axis formation & folding

Question 5

Where does fertilization take place?

Answer 5

Ampulla is the site of fertilization

Question 6

What steps are involved in fertilization?

Answer 6

1) Sperm binds
- in a human specific interaction with the zona pellucida glycoprotein
2) Acrosomal enzymes
- released from sperm head; the sperm digests its way into egg.
3) Membranes fuse
- Egg and sperm plasma membrane fuse and sperm contents enter the egg
4) Sperm entry triggers:
- completion of meiosis 2
- release of cortical granules by oocyte

Question 7

What is meant by ‘cleavage’ & ‘compaction’?

Answer 7

Cleavage describe the process where the zygote undergoes a series of mitotic divisions which subdivide the fertilised egg into many smaller daughter cells called blastomeres.
Compaction is when cells confined within zona pellucida move closer together and form cell junctions.

Question 8

Name the different parts of the blastocyst & what they give rise to.

Answer 8

Blastocyst cavity: fluid filled spacee
Trophoblast: is embryonic part of the placenta & :. connects to umbilical cord
Inner cell mass: makes embryo