Embryology Process:

Question 1

In Fertilisation what does the sperm bind with?

Answer 1

-Zona Pellucida Glycoprotein (ZP3)

Question 2

What does the sperm release into the Zone Pellucida Glycoprotein it fuses with>

Answer 2

-Acrosal-digetsive enzymes

Question 3

What happens after the egg and sperm fuse?

Answer 3

-Sperm releases its contents into egg

Question 4

What X2 things does the sperm entry trigger?

Answer 4

• Completion of Meiosis 2
• Release of Oocyte granules

During meiosis II, the sister chromatids within the two daughter cells separate, forming four new haploid gametes.

Question 5

What is an Oocyte?

Answer 5

Immature egg cell (Germline cell)

Question 6

What does Totipotent, Multipotent and Pluripotent mean?

Answer 6

Totipotent- Can differentiate into ALL Types of cells
Pluripotent-Can specialise into ALL cell types except embryonic and placental cells
Multipotent- Cann only specialise into cells of the tissue found in

Question 7

What is Compaction of the Morula and what does it form?

Answer 7

• Cells become tightly packed to increase surface area

- Forms- Blastocyst

Question 8

What is a Morula formed from?

Answer 8

-Blastomere

Question 9

What is Blastocyst Hatching?

Answer 9

Blastocysts bursts out of the Zona Pellucida Layer

-Interacts with endometrial lining of uterus for implantation

Question 10

What happens when there is an accumulation of fluid in the Blastocyst?

Answer 10

-Signals production of ‘Cysts’-sacs with fluid

Question 11

What is a Trophoblast?

Answer 11

-Outer cell layer of. Blastocyst

Question 12

What is the Bilaminar Embryo?

Answer 12

-Embryo attached to tissue

Question 13

How is the Bilaminar Embryo formed?

Answer 13

• Implantation

- Trophoblast attaches to endometrial tissue

Question 14

How are the two layers formed in a Bilaminar Embryo?

Answer 14

Inner cell mass of embryo divides into two layers to form a Bilaminar Embryonic disc

Question 15

Name the two layers formed in the Bilaminar Embryo.

Answer 15

• Hypoblast (front)

- Epiblast (back)

Question 16

What hormone does the Trophoblast release that is used in Pregnancy Tests?

Answer 16

-Human Chorionic Gonadotropin: (hCG)

Question 17

What is the Graafian follicle and Corpus Luteum?

Answer 17

• Graafian Follicle-Matures to release follicle, secretes oestrogen
• Corpus Luteum-Formed after ovulation, secretes progesterone in response to thicken

Question 18

What is the ‘Extraembryonic Mesoderm’ ?

Answer 18

• Thick Layer formed in the Bilaminar Embryo

- Degenerates to form ‘Chronic Cavity’

Question 19

What is combined to form the Umbilical Cord?

Answer 19

-Chronic Cavity + Connecting Stalk

Question 20

How is the Trilaminar Embryo formed and what are its three layers?

Answer 20

• Gastrulation-Migration of epiblast cells through Primitive Streak
• Ectoderm, Mesoderm and Endoderm

Question 21

What are the three parts of the Primitive Streak?

Answer 21

-X3 Parts;
Primitive Pit
Primitive Node
Primitive Groove

Question 22

Put in order:
Blastocyst 
Embryo
Zygote 
Blastomere

Answer 22

1) Zygote
2) Embryo
3) Blastomere (forms morula)
4) Blastocyst (formed by compaction of Morula)