Implantation

Question 1

……………. describes the process of attachment and invasion of the uterine endometrium by the blastocyst

Answer 1

Implantation

Question 2

Implantation begins about day …….. of the conceptus and is concluded by day ……

Answer 2

Implantation begins about day 5 of the conceptus and is concluded by day 12

Question 3

Mention the sites of normal implantation

Answer 3

superior, posterior or anterior endometrial wall.

Question 4

Mention the possible sites of abnormal implantation

Answer 4

• ovary
• uterine tubes
• interstitial uterine cervix
• anywhere in peritoneal cavity commonly in the pouch of douglas

Question 5

A common site for abnormal implantation in the peritoneal cavity is the …………..

Answer 5

Pouch of douglas

Question 6

……….. signals the process of implantation

Answer 6

Blastocyst hatching

Question 7

The dissolution of zona pellucida is facilitated by ……….

Answer 7

uterine secretions and possibly blastula secretion

Question 8

………….. reduces motility of blastocyst and potentiates attachment to ambient surface

Answer 8

Blastocyst hatching

Question 9

Blastocyst hatching occurs on day …….

Answer 9

Day 5 or 6

Question 10

Invasion of endometrial epithelium occurs on day ……

Answer 10

9

Question 11

Outline the process of endometrial invasion

Answer 11

• Trophoblastic cells in the embryonic pole advance into the endometrium,deferentiating into an inner mononucleated layer, cytotrophoblast and an outer multinucleated layer, syncytiotrophoblast.

• Cells in the cytotrophoblastic layer continually divide and migrate to the syncytiotrophoblastic layer.

• Syncytiotrophoblasts secrete proteolytic enzymes to break down extracellular matrix around cells.

• Vacuoles appear in the syncytiotrophoblast layer ,then enlarges into lacunae

• Adjacent endometrial tissue undergoes decidualization, which later spread to entire endometrium except the cervix

Question 12

Describe the lacunar stage

Answer 12

• Cells of the syncytiotrophoblast penetrate deep into the stroma and erode the endothelial lining of the maternal capillaries/sinusoids.

• Syncytial lacunae becomes continuous with the sinusoids

• Maternal blood enters the lacunar system

Question 13

The coagulation plug commences about day ……..and is usually completed by day ……..

Answer 13

The coagulation plug commences about day 9 and is usually completed by day 12

Question 14

…………. seals off of the penetration defect in the surface epithelium

Answer 14

A fibrin coagulum

Question 15

the endometrium is prepared for the reception and nourishment of the blastocyst during the …………… phase of the uterine cycle

Answer 15

the secretory phase

Question 16

Implantation takes place in the ………… of the uterus

Answer 16

usually in the upper part of the posterior wall near the midline

Question 17

The trophoblast at the region of contact with the endometrium proliferates and differentiates into two layers, namely;

Answer 17

cytotrophoblast or Langhans layer
syncytiotrophoblast

Question 18

Describe the cytotrophoblast

Answer 18

The cytotrophoblast is the inner layer and is made up of distinct or individual mononucleated cells that undergo mitosis.

Question 19

The syncytiotrophoblast is also called …………

Answer 19

Syncytium

Question 20

…………. is invasive, and invades the endometrium

Answer 20

The syncytiotrophoblast

Question 21

Describe the syncytiotrophoblast

Answer 21

The syncytiotrophoblast or snycytium consists of multinucleated cells that have lost their cell boundaries. They do not undergo mitosis.

Question 22

the blastocyst sinks beneath the uterine epithelium and becomes fully embedded in the endometrium by the …….. day

Answer 22

11th or 12th day

Question 23

The bleeding that occurs when the blastocyst sinks beneath the surface of the endometium is called …………

Answer 23

implantation bleeding

Question 24

When does implantation bleeding occur/

Answer 24

It occurs at about the time menstruation is due.

Question 25

What is the common cause of erroneous calculation of EDD?

Answer 25

In some women, the bleeding may be large enough to mimic or simulate the beginning of menstruation. This may lead to erroneous calculation of the expected date of delivery (EDD)

Question 26

How is EDD calculated?

Answer 26

Pregnancy lasts for 40 weeks (280 days). The EDD is calculated from the first day of the last menstrual period LMP, by adding 7 to the day and 9 to the month.

Question 27

Implantation near the internal OS occurs when ………….

Answer 27

when the disappearance of the zona pellucida is delayed

Question 28

Describe placenta praevia

Answer 28

The blastocyst may become implanted in the lower segment of the uterus, close to the internal os of the uterus. This leads to a condition called placenta praevia Later, as the placenta develops, it encroaches towards the cervical canal and may bridge it. Later in pregnancy or during delivery, the placenta may become detached from the uterus and severe bleeding may oc

Question 29

What is ectopic pregnancy?

Answer 29

Extrauterine or ectopic pregnancy occurs when the blastocyst becomes implanted at any site outside the uterus

Question 30

……….. is said to have occurred when the blastocysts implants in the uterine tube

Answer 30

Tubal pregnancy

Question 31

…….. is the commonest site of ectopic pregnancy

Answer 31

Ampulla of uterine tube

Question 32

Mention the parts of the uterine tube

Answer 32

Ampulla Isthmus Interstitial portion Infundibulum

Question 33

List the sites of abdominal cavity implantation

Answer 33

■ Broad ligament of the uterus ■ Mesentery of the small intestine ■ Rectouterine pouch (pouch of Douglas) ■ Ovary

Question 34

Excessive proliferation of the trophoblast may lead to a condition called…………..

Answer 34

hydatidiform mole

Question 35

Describe hyadatiform mole briefly

Answer 35

Excessive proliferation of the trophoblast may lead to a condition called hydatidiform mole. The trophoblastic cells are converted into masses of grape-like vesicles. The uterus becomes filled with these vesicles and the fetus dies.

Question 36

………… is a hormone that is in high levels in hyadatiform mole

Answer 36

Human chronic gonadotropin

Question 37

……….. is said to have occurred when fertilization and implantation occur while the ovum is still in the ovary

Answer 37

Primary ovarian pregnancy

Question 38

Describe the uterus at the time of implantation

Answer 38

The mucosa of the uterus is in secretive phase The uterine glands and arteries are coiled & the tissues are succulent 3 distinct layers of are recognized in the endometrium; - Superficial compact layer - Intermediate sponge layer - Thin basal layer