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43 Cards in this Set
- Front
- Back
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What is sperm capacitation?
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Functional changes of the sperm to allow penetration of the zone pellucida.
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What is the acrosomal reaction?
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Release of proteolytic enzymes within the acrosomal membrane of the sperm that permit attachment to the zona pellucida (ZP3 receptors).
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What are the 3 proteolytic enzymes released in the acrosomoal reaction?
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1) hyaluronidase
2) acrosin 3) neuroamidase |
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How is multiple sperm attachment to a single egg (polyspermy) prevented?
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The first penetrating spermatozoa triggers an increase of Ca, which causes degranulation of the plasma membrane vesicles, releasing enzymes that harden the zona pellucida.
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What else occurs as a result of an increase in Ca?
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The second meiotic division is allowed to continue, fusion with sperm produces zygote formation.
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How long does it take for sperm to appear in the ampulla, post-coitus?
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5-6 minutes.
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How many viable sperm make it to the oviduct?
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0.1%
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How long can a sperm survive, retaining its ability to fertilize?
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24-48 hrs.
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What time in the woman's cycle is optimal for fertilization?
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Within 24 hrs. of ovulation.
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How does estrogen affect sperm transport?
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The female tract becomes watery and more viable for sperm to survive and travel.
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How does cGMP affect sperm transport?
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Increases its velocity and directionality.
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How does the basic environment of the vagina affect sperm transport?
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Increases sperm transport.
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How does the oviduct/fallopian tube aid in sperm transport?
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Increase ciliary movement, peristaltic contractions, and fluid flow push sperm toward the ampulla.
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What draws the oocyte out of the ovary?
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Fimbriae.
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What feature of the ampulla increases probability of fertilization?
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Contraction and churning of the ampulla wall.
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How long does the morula/blastocyst require to get through the oviduct?
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About 3 days.
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What determines the timing and arrival of the morula/blastocyst to the uterine cavity?
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Progesterone and estrogen balance.
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How does estrogen affect morula/blastocyst transport?
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Stimulates constriction of the isthmus to prevent uterine entry, probably to allow endometrium more time to develop.
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How does progesterone affect morula/blastocyst transport?
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Stimulates myometrium relaxation and facilitates transport to the uterus.
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What are the 3 processes of implantation to the endometrium?
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1) Adhesion
2) Penetration 3) Invasion |
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What is the first step of adhesion?
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Zone pellucida dissolves.
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How does progesterone affect adhesion?
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I don't know. Find this out.
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What are integrins?
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Binding molecules that connect endometrial cells to each other, and blastocyst cells to each other.
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What cytokine will be released during adhesion and what is its function?
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IL-1.
Increase integrins in the endometrial cells. |
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What is osteopontin?
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It is a molecule that binds to integrins of endometrium and to those of the blastocyst.
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What is the trophoblast?
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A region that extends from the blastocyst and latches on to endometrial cells via laminin and fibronectin, both of which induce adhesion.
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What is the role of decidual cells?
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It grows as a source of nutrients, a mechanical and immune barrier, and as an endocrine gland.
(I think this will eventually aid in penetration.) |
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How does invasion progress?
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Trophoblasts from fetus and decidual cells from mother must coordinate to cause invasion.
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What is the role of IGF-2 and IGF-BP in invasion?
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They stimulate invasion.
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What are syncytiotrophoblasts and what do they do?
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Placental cells that are
analagous to the pituitary - responsible for most hormone production. |
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What are cytotrophoblasts and what do they do?
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Placental cells that are an analog to the hypothalamus in that it produces stimulatory and inhibitory control over the syncytiotrophoblast.
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What is the primary role of oral contraceptives?
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Prevent ovulation.
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How do oral contraceptives affect the pituitary and hypothalamus?
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Suppress LH surge, thus preventing ovulation. Supress basal gonadotropin levels. Suppress FSH preventing follicular growth.
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How do oral contraceptives affect the fallopian tube?
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Decreases its motility.
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How do oral contraceptives affect the endometrium?
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Cause glandular atrophy, which prevents implantation.
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How do oral contraceptives affect the cervical mucus?
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Thickens it, inhibiting sperm motility and transport.
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What are the 3 types of oral contraceptives and how do they work?
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1) Fixed combination - constant estrogen and progestagen throughout the cycle.
2) Biphasic and triphasic - constant estrogen, variable progestagen. 3) Progestagen-only |
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What are the risks of oral contraception?
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Hypertension, myocardial infarction, stroke - contraindicated in heavy smokers over 35, and history of estrogen-dependent breast carcinomas.
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What are 4 benefits of oral contraception?
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1) Treatment of excessive bleeding
2) Aid in dysmenorrhea 3) Hormone replacement for post-menopausal women 4) Protect against pelvic inflammatory disease. |
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What are 4 ways to prevent contact of germ cells to avoid fertilization?
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1) Abstinence
2) Coitus interruptus (pulling out) 3) Physical barriers: condoms, diaphragms, cervical caps (together with spermicides). 4) Periodic abstinence around the time of ovulation. |
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What are 3 ways to prevent implantation of the fertilized egg?
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1) High doses of estrogen
2) Progesterone receptor antagonist (RU486) 3) IUD provokes sterile inflammation of the endometrium, preventing implantation. |
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What are 2 methods of abortion?
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1) Prostaglandin administration will increase uterine contraction and terminate pregnancy.
2) Surgical removal - dilatation and curettage. |
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What are the 3 functions of the placenta?
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1) Transport of nutrients
2) Removal of waste products 3) Endocrine hormone release - cytotrophoblasts and syncytiotrophoblasts |
