Embryology

Question 1

Describe what happens within the first 12-24 hours of ovulation.

Answer 1

Sperm and ovum meet in uterine tube.
They fuse together and 2nd meiotic division occurs.
Acrosome reaction makes ovum impermeable to other sperm.
Diploid zygote forms.
Cleavage occurs

Question 2

Describe what happens 30 hours after fertilisation.

Answer 2

1st mitotic division occurs and each cell is called a blastomere. A solid sphere of these cells is called a morula.

Question 3

What type of cells do embryoblasts give rise to?

Answer 3

Hypoblasts and Epiblasts

Question 4

2 Functions of the epiblasts

Answer 4

Give rise to the germ layers- ectoderm, mesoderm and endoderm

Allow formation of the amniotic cavity

Question 5

What is gastrulation?

Answer 5

The process by which the three germ layers and the embryonic pole are established.

Question 6

What is the role of the primitive streak in gastrulation?

Answer 6

It initiates formation of the three germ layers

Question 7

What cells originate from the ectoderm layer?

Answer 7

Nervous system. ears, skin and eyes

Question 8

What systems originate from the mesoderm?

Answer 8

Skeletal system, renal system and muscular system.

Question 9

What system originates from the endoderm?

Answer 9

Gastrointestinal system