Fertilization & Implantation

Question 1

How does cervical mucous change in response to oestrogen?

Answer 1

Increases volume
Decreases viscosity (clear, watery mucous)
High threadability
Receptive to sperm - contains channels for sperm access

Question 2

How does cervical mucous change in response to progesterone?

Answer 2

Highly viscous
Cross linked
Barrier to sperm penetration

Question 3

Primordial follicle:

Following a ___ surge meiosis is resumed and the first division is completed (stops at ____)

Answer 3

LH

Second metaphase

Question 4

Mixing of prostatic and seminal fluids in vagina -> ____ holding ejaculate together -> adheres ejaculate to female reproductive tract

Answer 4

Coagulum

Question 5

____ occurs within 2-15 mins of ejaculation

Answer 5

Liquefaction

Question 6

Vaginal pH is normally __ but is buffered by seminal plasma to around ___

Answer 6

4. 7

7. 2

Question 7

How do the tails of normal sperm affect cervical mucus?

Answer 7

Causes fibres of cervical mucus to vibrate in rhythm -> facilitate movement

Question 8

A patient trying to avoid pregnancy should avoid intercourse within __ days of ovulation

Answer 8

5

Question 9

What are the survival times of sperm:

Vagina
Cervix
Uterus
Oviduct

Answer 9

Vagina - 2.5h
Cervix - 48h
Uterus - 24h
Oviduct - 48h

Question 10

It takes the sperm approx. ___ hours to reach the ampulla.

Answer 10

2-7

Question 11

Where does fertilisation usually occur?

Answer 11

In the isthmus-ampulla junction of the fallopian tubes

Question 12

Sperm arriving in the uterus induces an infiltration of _____

Answer 12

Leucocytes

Question 13

What changes occur in sperm during capacitation?

Answer 13

• Removal of capacitation inhibitory substances
• Loss of cholesterol from membrane
• Sperm hyperactivation

Question 14

What is contained in the acrosome?

Answer 14

Proteinases and other enzymes

Question 15

What are the two known triggers of the acrosome reaction?

Answer 15

Progesterone and ZP3

Question 16

_____ secreted from the acrosome digests the basement membrane to assist sperm squeezing between cumulus cells

Answer 16

Hylauronidase

Question 17

Enzymes of acrosome assist sperm penetration through the Zona pellucida to the _____ space

Answer 17

Perivitelline

Question 18

Entry of a sperm into the oocyte triggers a release of intracellular ____

Answer 18

Calcium

Question 19

_____ are released into the perivitelline space in the cortical reaction

Answer 19

Cortical granules

Question 20

Release of cortical granules causes ____ of the zona pellucida

Answer 20

Cross-linking

Question 21

How does Ca influx post fertilisation cause meiosis resumption?

Answer 21

• Destabilises a protein complex holding chromosomes together in metaphase
• Chromosomes migrate to poles for meiosis to resume

Question 22

The zygote ~___ days to traverse the tube and enter the uterus

Answer 22

5

Question 23

The embryo is called the morula at the ___ cell stage

Answer 23

16

Question 24

The embryo is called the blastocyst at the ___ cell stage

Answer 24

60

Question 25

Trophodecterm eventually forms the _____ whereas the inner cell mass forms the ____ and ____

Answer 25

Trophoblast (of the placenta)

Body of foetus proper + extra embryonic structures that aren’t trophoblast derived

Question 26

What is nidation?

Answer 26

The process by which the embryo burrows into the endometrium of the uterus.

Question 27

The embryo always attaches to the dedicudalendometrial epithelium via the _____

Answer 27

Polar trophectoderm