Lect. 8 - Implantation

Question 1

How soon after ovulation does fertilization typically occur?

Answer 1

12 hours. (in upper ampulla)

Question 2

Uterine tube transport - End of day 1

Answer 2

2-cell stage in isthmus

Question 3

uterine tube transport - day 3

Answer 3

morula in isthmus/corona radiata lost by this time

Question 4

uterine tube transport - day 4

Answer 4

blastocyst in uterus

Question 5

uterine tube transport - day 5

Answer 5

loss of ZP

Question 6

uterine tube transport - day 6

Answer 6

beginning of implantation

Question 7

Blastocyst hatching

Answer 7

A small region of the ZP, usually directly over the ICM in the primate, dissolves and the blastocyst emerges from the hole.

Question 8

major functions of the ZP

Answer 8

promotes maturation of the oocyte and follicle;
barrier; initiates the acrosomal reaction; prevents any additional sperm from reaching the zygote; porous filter through which certain substances secreted by the uterine tube can reach the embryo; immunological barrier b/w the mother and the antigenically embryo; prevents the blastsulas of the early cleaving embryo from dissociating; differentiation of trophoblastic cells; prevents premature implantation of the cleaving embryo into the wall of the uterine tube.

Question 9

Stages of implantation

Answer 9

1. attachment of expanded blastocyst to the endometrial epithelium
2. penetration of the uterine epithelium
3. invasion into the tissues underlying the epithelium
4. erosion of the maternal vascular supply

Question 10

what facilitates attachment of the blastocyst to the endometrium?

Answer 10

adhesion molecules expressed by the endometrium and also by the trophoblast cells

Question 11

cytotrophoblast

Answer 11

closest to ICM

Question 12

syncytiotrophoblast

Answer 12

closest to endometrium; its projections penetrate the endometrial basal lamina and invade the stroma

Question 13

decidual reaction

Answer 13

response of the endometrial stroma cells to the invading blastocyst

Question 14

what would happen w/o the decidual reaction?

Answer 14

possible the trophoblast would erode through the endometrial wall

Question 15

what are decidual cells derived from?

Answer 15

endometrial stroma cells that accumulate glycogen and lipid droplets

Question 16

result of the decidual reaction

Answer 16

massive cellular matrix that completely surrounds the embryo and fills most of the endometrium

Question 17

IL-2 in the decidual reaction

Answer 17

prevents the mother’s immune system from recognizing the embryo as a foreign body
**primary function

Question 18

most common place for ectopic pregnancies to occur

Answer 18

uterine tube

Question 19

w/i the uterine tube, where is the most common place for ectopic pregnancies

Answer 19

ampulla

Question 20

if ectopic pregnancy happen outside of the reproductive system where’s most common?

Answer 20

rectouterine pouch

Question 21

where is low pH most important?

Answer 21

vagins

Question 22

transcription of what is required to permit cleavage to proceed to the 2-cell stage in mammalian embryos

Answer 22

Oct 4