Fertilization, Implantation, Placental Development

Question 1

Where are the receptors for sperm on the oocyte located?

Answer 1

Zona pellucida

Question 2

What must happen in order for fertilization to occur

Answer 2

• Removal of epididymal and seminal glycoproteins.

- Increase in membrane permeability to Ca2+.

Question 3

What are the three main events that occur in fertilization after the sperm has found the egg?

Answer 3

• acromsome reaction
• sperm binding to ZP3
• sperm-egg fusion

Question 4

How is polyspermy inhibited?

Answer 4

Via the cortical reaction.

Question 5

What protein is required for sperm to fuse with the egg?

Answer 5

Izumo (sperm) binds to CD9 on the egg

Question 6

What is the fast component of the cortical reaction?

Answer 6

Change in resting potential of oocyte plasma membrane, thus preventing further binding of sperm.

Question 7

What is the slow component of the cortical reaction?

Answer 7

Release of cortical granules containing enzymes (into PVS) that destroy sperm receptors (ZP2 and ZP3).

Question 8

After fertilization, what are the next stages of development?

Answer 8

Development of the morula-> blastocyst , with outer trophoblast and inner cell mass surrounding the blastocyst cavity.

Question 9

What must occur before implantation of the blastocyst?

Answer 9

Hatch from the Zona pellucida

Question 10

Implantation is mediated by what cells?

Answer 10

Penetrating trophoblastic cells.

Question 11

What cells will invade and penetrative the endometrium?

Answer 11

Synctiotrophoblast

Question 12

What are decidual cells?

Answer 12

Cells full of lipids and glycoproteins. Provide nutrients to the developing embryo.

Question 13

What are the spaces created by the Synctiotrophoblast once they come in contact with the mothers vascular supply?

Answer 13

Lacunae

Question 14

What secretes hCG?

Answer 14

Synctiotrophoblast

Question 15

The secretion of estrogens and progesterone is under the control of what?

Answer 15

Corpus luteum under the control of hCG.

Question 16

What is a primary villus?

Answer 16

Outgrowth of the cytotrophoblast into the Synctiotrophoblast

Question 17

What is a secondary villi?

Answer 17

Extraembryonic mesoderm enters the primary villi.

Question 18

What is a tertiary villi?

Answer 18

Cells of the XE mesoderm will differentiate into capillaries

Question 19

What are the maternal parts of the placenta?

Answer 19

Decidua basalis

Question 20

What is the part of the placenta that comes from the embryo?

Answer 20

Chorion frondosum

Question 21

What part of the embryo overlies the implanted embryo and separates it from the uterine cavity?

Answer 21

Decides capsularis

Question 22

What is the basic structure involved in maternal-fetal exchanges?

Answer 22

Chorionic villus

Question 23

What are the layers that make up the placental barrier?

Answer 23

• Synctiotrophoblast
• cytotrophoblast
• extraembryonic mesenchyme
• fetal endothelium

Question 24

What is a placenta abruption?

Answer 24

Premature separation of the normally implanted placenta. Blood will begin to pool into the Decidua basalis.

Question 25

What is a placental Previa?

Answer 25

Implantation of the placenta over the cervical os

Question 26

What is uterine Atony?

Answer 26

Contractions of the uterine muscles are not strong enough to close the spiral arteries and postpartum bleeding occurs.

Question 27

What is gestational trophoblastic disease?

Answer 27

Group of neoplasms that arise from fetal tissue invading the maternal host

Question 28

What is a complete hydatifiform mole?

Answer 28

No fetus. Fertilization of egg which has lost its chromosomes by 2 sperm or 1 sperm. *chromosomes are only paternal*

Question 29

What is a partial hydatifiform mole?

Answer 29

Maternal chromosomes are present but extra paternal chromosomes are present.

Question 30

What is the karyotype of a partial mole?

Answer 30

Tripoidy or tetraploidy.

Question 31

What is the karyotype of a complete mole?

Answer 31

46XX or 46XY paternal origin

Question 32

Is there fetal tissue present a complete mole and incomplete mole?

Answer 32

Complete-> absent | Incomplete-> present

Question 33

What is the scope of hydronic villi in a complete mole and incomplete mole?

Answer 33

Complete-> extensive Incomplete-> limited and focal

Question 34

What are the types of malignant gestational trophoblastic disease?

Answer 34

- Invasive mole-> invasion into myometrium. Choriocarcinoma. - Placental-site trophoblastic tumor - Choriocarcinoma.

Question 35

What meiotic stage is the ovulated oocyte in?

Answer 35

Secondary oocyte that has not completed the second meiotic division

Question 36

What makes up the chorion?

Answer 36

Synctiotrophoblast, cytotrophoblast, extraembryonic mesoderm

Question 37

What part of the placenta makes up the portion underlying the implantation site and forms the maternal part of the placenta?

Answer 37

Decidua basalis

Question 38

What is placenta accreta?

Answer 38

Abnormal trophoblastic invasion into the myometrium