TBL: Pregnancy Flashcards
What cells produce estrogen?
granulosa and thecal cells
Estrogen: granulosa and thecal cells (blank) of endometrium (blank) of the cervical mucus Stimulate pituitary to secrete (blank) LH surge at mid-cycle-> (blank) Stimulate (blank) production
proliferation; thinning; LH; ovulation; progesterone
What causes the completion of meiosis I and the transformation into a Graffian/preovulatory follicle?
LH surge
Graffian follicles are arrested in what phase 3 hours before ovulation?
metaphase of meiosis II
Ovarian surface:
LH↑→ (blank) ↑→ Digestions of fibers around the follicle
LH↑→ (blank) ↑→ Muscular contraction
collagenase; prostaglandin
During ovulation, what increases digestions of fibers around the follicle?
increased LH leading to increased collagenase
During ovulation, what increases muscular contraction?
increased LH leading to increased prostaglandin
The corpus luteum contains these two types of lutean cells
granulosa cells
thecal cells
The corpus luteum secretes primarily (blank)
progesterone
Together, progesterone and estrogen prepare the uterine mucosa for implantation by eliciting the (blank) stage
progestational/secretory
How is the ovulated oocyte transported?
Ovulated oocyte is captured by the sweeping movement of the fimbriae of the uterine tube and by the motion of cilia on the epithelial lining
How long does it take for the oocyte to move from the ampulla to the uterine lumen?
3-4 days
Where does fertilization occur in the uterine tube?
at the ampulla
If there is no fertilization, what does the corpus luteum form? What steroid declines? What occurs?!
lutean cells apoptosis, forms corpus albicans, progesterone decreases, menstrual bleeding begins
If the oocyte gets fertilized, what is secreted by the syncytiotrophoblast to promote further growth?
hCG
Progesterone production will continue until what month? At this point, trophoblastic secretion of progesterone becomes adequate.
4th month
Discuss the transport of sperm from the testis to ejaculation.
testis –> epididymis (maturation for 2 weeks) –> rapid transit through ductus deferens –> addition of fluid from seminal vesicle –> addition of prostatic fluid
Discuss the transport of sperm as it enters the vag
Sperm deposited in upper vag –> pass through cervix (fast and slow phase) –> pass through uterus –> enter uterine tubes –> traverse uterine tube by swimming and contractions of the tube –> only a small number of sperm actually near the egg at a given time
250,000,000 sperm are deposited in the vagina, and 100,000 sperm reach the uterine cavity. How many sperm arrive at the distal end of the fallopian tube?
50 or less
Once they’ve come through the vag, the cervix, the uterus, where are sperm delayed? For how long?
delayed at isthmus-ampulla junction where fertilization occurs (1-2 days)
delayed at utero-tubal junction (2-3 days)
At what day does the egg enter the uterine cavity as a morula?
Days 3-4
At what day does the blastocyst implant?
Day 7
Maturation of sperm in female reproductive tract → Removal of the glycoprotein coat and seminal plasma proteins from the sperm plasma membrane
Capacitation
Release of enzyme by sperm to dissolve zona pellucida
Acrosome reaction
3 phases of fertilization
- penetration of the corona radiata
- penetration of the zona pellucida
- fusion of the oocyte and sperm cell membranes
Steps 1-5 of fertilization
- sperm penetrates zona pellucida (15-25 mins)
- perivitelline space (<1 min)
- perivitelline membrane
- release of cortical granules
- completion of second meiotic division and formation of polar body - male and female pronuclei visible (2-3 hours)
- mitotic spindle and first cleavage (24 hours)
3 things that entry of sperm into the oocyte triggers
- cortical and zona reactions to prevent polyspermy
- oocyte completes meiosis II
- egg is activated
Sperm enters egg causing rapid depolarization of plasma membrane of egg - hardening of zona pellucida and inactivation of sperm receptors - second meiotic division and cortical reaction completed - male pronucleus forming - female pronucleus forming - pronuclei join - metaphase of first cleavage division
Main events during fertilization
3 results of fertilization:
restoration of diploid number of chromosomes
sex determination
initiation of cleavage
Blastomeres begin to form in 2, 4, and 8 cell stages and become compact. The inner and outer cells become (blank). The blastomeres become a (blank) on day 3 and there are about 16 cells.
segregated; morula
By day 3, in the morula, the inner cell mass becomes the (blank) while the outer cell mass becomes the (blank)
embryo proper; trophoblast
At about day 4, the differentiated morula will become a (blank) - the ZP degenerates, uterine fluid penetrates - a blastocele (cavity) forms and the inner cell mass becomes the (blank), while the outer cell mass becomes the (blank)
blastocyst; embryoblast; trophoblast
At about what day does the blastocyst implant in the uterine wall?
Day 5.5 - 6