Implantation Flashcards
……………. describes the process of attachment and invasion of the uterine endometrium by the blastocyst
Implantation
Implantation begins about day …….. of the conceptus and is concluded by day ……
Implantation begins about day 5 of the conceptus and is concluded by day 12
Mention the sites of normal implantation
superior, posterior or anterior endometrial wall.
Mention the possible sites of abnormal implantation
- ovary
- uterine tubes
- interstitial uterine cervix
- anywhere in peritoneal cavity commonly in the pouch of douglas
A common site for abnormal implantation in the peritoneal cavity is the …………..
Pouch of douglas
……….. signals the process of implantation
Blastocyst hatching
The dissolution of zona pellucida is facilitated by ……….
uterine secretions and possibly blastula secretion
………….. reduces motility of blastocyst and potentiates attachment to ambient surface
Blastocyst hatching
Blastocyst hatching occurs on day …….
Day 5 or 6
Invasion of endometrial epithelium occurs on day ……
9
Outline the process of endometrial invasion
• 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
Describe the lacunar stage
• 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
The coagulation plug commences about day ……..and is usually completed by day ……..
The coagulation plug commences about day 9 and is usually completed by day 12
…………. seals off of the penetration defect in the surface epithelium
A fibrin coagulum
the endometrium is prepared for the reception and nourishment of the blastocyst during the …………… phase of the uterine cycle
the secretory phase
Implantation takes place in the ………… of the uterus
usually in the upper part of the posterior wall near the midline
The trophoblast at the region of contact with the endometrium proliferates and differentiates into two layers, namely;
cytotrophoblast or Langhans layer
syncytiotrophoblast
Describe the cytotrophoblast
The cytotrophoblast is the inner layer and is made up of distinct or individual mononucleated cells that undergo mitosis.
The syncytiotrophoblast is also called …………
Syncytium
…………. is invasive, and invades the endometrium
The syncytiotrophoblast
Describe the syncytiotrophoblast
The syncytiotrophoblast or snycytium consists of multinucleated cells that have lost their cell boundaries. They do not undergo mitosis.
the blastocyst sinks beneath the uterine epithelium and becomes fully embedded in the endometrium by the …….. day
11th or 12th day
The bleeding that occurs when the blastocyst sinks beneath the surface of the endometium is called …………
implantation bleeding
When does implantation bleeding occur/
It occurs at about the time menstruation is due.
What is the common cause of erroneous calculation of EDD?
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)
How is EDD calculated?
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.
Implantation near the internal OS occurs when ………….
when the disappearance of the zona pellucida is delayed
Describe placenta praevia
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
What is ectopic pregnancy?
Extrauterine or ectopic pregnancy occurs when the blastocyst becomes implanted at any site outside the uterus
……….. is said to have occurred when the blastocysts implants in the uterine tube
Tubal pregnancy
…….. is the commonest site of ectopic pregnancy
Ampulla of uterine tube
Mention the parts of the uterine tube
Ampulla
Isthmus
Interstitial portion
Infundibulum
List the sites of abdominal cavity implantation
■ Broad ligament of the uterus
■ Mesentery of the small intestine
■ Rectouterine pouch (pouch of Douglas)
■ Ovary
Excessive proliferation of the trophoblast may lead to a condition called…………..
hydatidiform mole
Describe hyadatiform mole briefly
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.
………… is a hormone that is in high levels in hyadatiform mole
Human chronic gonadotropin
……….. is said to have occurred when fertilization and implantation occur while the ovum is still in the ovary
Primary ovarian pregnancy
Describe the uterus at the time of implantation
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
