3-Ovulation, Fertilization... Flashcards
Late primary follicle
- multilaminar now called granulosa cells
Gel-like substance rich in GAGs
Zona pellucida
- ovulation to implantation
- embryonic period
- fetal stage
Prenatal develop
First 8 weeks
Embryonic period
8 weeks till birth
Fetal stage
In ovulationThe secondary follicle grows rapidly under the influence
of FSH and LH
Meiosis II is initiated but the Oocyte is arrested in
Metaphase
High concentration of LH increases
Collagenase activity
Stimulates production of progesterone by follicular stromal cells
Luteinization
increase in response to LH and cause local muscular contractions in the ovarian wall.
Prostaglandin
Corpus luteum are yellowish which are developed under the effect of which hormone and secrete progesterone?
LH
What causes the uterine mucosa to enter the secretory phase ( preparation for implantation)?
Progesterone
The oocyte is viable for how many hours?
12-24 hours
The sperm is viable for how much hours?
24-72 hours
For fertilization to occur, coitus must occur no more than
- Three days before ovulation
* 24 hours after ovulation
when a sperm fuses with an egg to form a zygote
Fertilization
Capacitation
a period of conditioning in the female reproductive tract.
In human lasts approximately 7 hrs.
Capacitation
Capacitation
Occurs more in the uterine tube
Capacitation
Epithelial interactions between the sperm and mucosal surface of the tube
glycoprotein coat and seminal plasma proteins are removed from the plasma membrane that overlies the acrosomal region of the spermatozoa.
During the time of capacitation
An ovulated oocyte is encapsulated by:
- The corona radiata and zona pellucida
* Extracellular matrix
Hundreds of acrosomes release their enzymes to digest the
Zona pellucida
Once a sperm makes contact with the oocyte’s membrane:
- Beta protein finds and binds to receptors on the oocyte membrane
- Alpha protein causes it to insert into the membrane
increase in cellular respiration and protein synthesis in egg
Egg activation
Only one sperm is allowed to penetrate the oocyte
Block to poly spermy
Completion of Meiosis II
Upon entry of sperm
when the pronuclei come together
Fertilization
The first cleavage produces two daughter cells called
blastomeres
the 16 or more cell stage (72 hours old)
Morula
the preembryo consists of 100 or so cells (blastocyst)
By the fourth or fifth day
a fluid-filled hollow sphere composed of:
• A single layer of trophoblasts
• An inner cell mass
Blastocyst
take part in placenta formation
Trophoblasts
becomes the embryonic disc
The inner cell mass
Implanting blastocyst
6 days
Implantation of the Blastocyst
Begins six to seven days after ovulation when the trophoblasts
adhere to a properly prepared endometrium
Syncytiotrophoblast
cells in the outer layer that lose their plasma membranes and invade the endometrium secret human chorionic gonadotropin (hCG)
Implantation is completed by
the fourteenth day after ovulation
Viability of the corpus luteum is maintained by
human chorionic gonadotropin (hCG) secreted by the trophoblasts
hCG prompts the corpus luteum to continue to secrete
progesterone and estrogen
Between the second and third month, the placenta:
- Assumes the role of progesterone and estrogen production
* Is providing nutrients and removing wastes
The most common form of human ectopic pregnancy is described as a
tubal
pregnancy (implantation occurs within the uterine tube).
Ectopic pregnancies are therefore often identified by
early ultrasound scans.
• The risk factors for tubal ectopic pregnancy include:
- Tubal damage by infection (particularly Chlamydia trachomatis) or surgery, smoking and in vitro fertilization therapy.
- Prolonged tubal damage is often described as pelvic inflammatory disease and , can affect the cilia- mediated transport of the blastocyst during the first week of development.
