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210 Cards in this Set
- Front
- Back
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What does it mean for germ cells to be totipotent?
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Germ cells can form any cell in the organism, including extra-embryonic tissues.
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What does it mean for some somatic cells to be pluripotent?
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Some somatic cells can form any fetal or adult cells in any of the three germ layers, but they cannot form extraembryonic tissue, so they cannot give rise to a fetal or adult organism
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What is the route of primordial germ cell migration?
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Origin: primary ectoderm and then migrate to the endoderm/mesoderm of yolk sac wall
Migrate to hindgut at 4-5 weeks, then through the dorsal mesentery to the primordial gonad in the urogenital ridge |
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What do the primoridal germ cells do once they reach the primordial ridges?
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Stop moving, proliferate, enter meiosis (in females), enter mitotic arrest (in males), and then arrange into sex cords
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How do primordial germ cells induce gonads to form?
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They stimulate cells of the adjacent coelomic epithelium and mesonephros to proliferate and form compact strands of tissue called primitive sex cords
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What supportive cells are the sex cords precursors to?
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Sertoli cells and granulosa cells
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How does the sex of the germ cells determine gonadal sex in the male?
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Testis-determining factor from the SRY gene on the Y chromosome upregulates production of steroidogenesis factor (SF1) via Sox9 to stimulate differentiation of Leydig and Sertoli cells. Anti-Mullerian hormone from the Sertoli cells degrades the Mullerian ducts and testosterone from the Leydig cells preserves the Wolffian ducts.
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How does the sex of the germ cells determine gonadal sex in the female?
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The absence of SRY in females means that the cells form granulosa cells and thecal cells. There are no Sertoli cells to secrete AMH, so the Mullerian ducts remain and there are no Leydig cells to secrete testosterone to preserve the Wolffian ducts, so they degenerate
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What four structures are present as part of the indifferent gonad?
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Gonad, mesonephros, Wolffian duct, and Mullerian duct
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What structures are formed from the Mullerian duct in the female?
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Oviducts, uterus, cervix, and the upper third of the vagina
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What structures are formed from the Wolffian duct in the male?
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Epididymis, vas deferens, seminal vesicles, and ejaculatory duct
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Which protein is needed to convert testosterone to DHT?
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5-alpha-reductase
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In the absence of testosterone, which external genitalia form?
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Clitoris, labia majora, labia minora
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In the presence of testosterone, which genitalia are formed?
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Prostate, bulbourethral gland, penis, and scrotum
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Which gamete provides the zygote with most of its cytoplasm?
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The oocyte.
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What are three functions of Sertoli cells?
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1. The Sertoli cells provide nutrients to the differentiating sperm 2.) Sertoli cells form tight junctions with each other, creating the blood-testes barrier. The blood-testes barrier imparts a selective permeability, admitting "allowable" substances such as testosterone to cross but prohibiting noxious substances that might damage the developing sperm. 3.\) Sertoli cells secrete an aqueous fluid into the lumen of the seminiferous tubules, which helps to transport sperm through the tubules into the epididymis.
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Spermatogonia
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Sperm germ cells that are activated at puberty to either divide by mitosis to make more germ cells (Type A spermatogonia) or to enter meiosis to become sperm (Type B primary spermatocytes)
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Where does spermatogenesis occur?
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The seminiferous tubules
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Primary spermatocyte
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Spermatogonia that have entered meiosis
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Secondary spermatocyte
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Have completed meiosis 1. Daughter cells are 1n2d
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Spermatids
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Have completed meiosis 2. 1n1d. Cells are still connected to each other for coordination purposes.
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Spermiogenesis
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The process by which spermatids become mature sperm. The spermatids become spermatozoa with their heads embedded in pockets between Sertoli cells and their tails protrude into the lumen of the seminiferous tubule
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Spermiation
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The process by which the heads of the spermatozoa are released from the Sertoli cells.
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What controls the transition from a primordial follicle to a primary follicle in the ovary?
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Kit ligand released by the granulosa cells and BMPs released by the ovarian stroma initiate follicle growth.
Kit ligand recruits thecal cells from the stroma. BMP4 from the recruited theca supports oocyte survival. BMP15 and GDF-9 made by the oocyte stimulate further granulosa cell proliferation and transition to a multi-layered follicle. |
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Which parts of oogensis are controlled by the pituitary?
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Formation of antral follicles. Resumption of meiosis. Ovulation.
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What is the role of FSH in oogenesis?
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The granulosa cells are the only ovarian cells with FSH receptors. Initial actions of FSH stimulate the growth of granulosa cells in primary follicles and stimulate estradiol synthesis. The locally produced estradiol then supports the trophic effect of FSH on follicular cells. Thus, the two effects of FSH on the granulosa cells are mutually reinforcing: more cells, more estradiol, more cells.
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What is the role of LH in oogenesis?
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Ovulation is initiated by LH. Just prior to ovulation, the concentration of LH in blood rises sharply and induces rupture of the dominant follicle, releasing the oocyte. LH also stimulates formation of the corpus luteum, a process called luteinization, and maintains steroid hormone production by the corpus luteum during the luteal phase of the menstrual cycle.
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Which stage of meiosis is the egg in after ovulation?
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It is arrested in metaphase of meiosis II.
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How does the egg enter the Fallopian tube?
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It is swept into the abdominal ostium by the fimbriae of the infundibulum.
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What structure becomes the corpus luteum?
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The ruptured follicle that released the egg.
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About how long does it take for an oocyte to fully mature from a primary follicle to a pre-ovulatory follicle?
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85 days
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What is a selection factor for follicles continue to undergo maturation?
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Their sensitivity to the estradiol released by the granulosa cells.
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How many oocytes are present in the fetus by the end of the second trimester?
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Between 6 and 7 million
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Why do so many oocytes die before birth?
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If an oocyte is not able to associate with a granulosa cell, it dies. There aren't enough granulosa cells to associate with all of the eggs.
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What is one major difference about the timing of the onset of gametogenesis between males and females?
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Male spermatogonia are dormant until they receive the testosterone signal at puberty to begin spermatogenesis. Female oogonia begin dividing in fetal life and are arrested in the diplotene stage of meiosis I until ovulation.
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How many sperm are produced from a spermatogonium?
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Four
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What are the products of the meiosis of one oogonium?
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One oocyte and 3 polar bodies.
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What are three functions of meiosis?
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1) Produces haploid cells for sexual reproduction
2) Provides for constancy in chromosome number over the generations 3) Generates genetic diversity |
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What are the two main causes of aneuploidy?
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Nondisjuction and translocation
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What results from a non-disjunction during cleavage?
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A mosaic individual
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Which forms of aneuploidy are viable in humans?
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Trisomy 21, 13, and 18
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What are two methods by which aneuploidy can be detected?
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Amniocentesis and chorionic villi sampling
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What percentage of spontanous abortions are due to aneuploidy?
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60%
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Parthenogenesis
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When an unfertilized egg initiates development
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When do the chorionic villi form?
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Week 3
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What are three main causes of infertility?
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1) Failure to produce/deliver sperm or eggs
2) Defects in fertilization 3) Defects in embryonic development (implantation) |
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What is a conceptus?
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A developing offspring
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What marks the beginning and end of the gestation period?
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The beginning of the last menstrual period and birth, respectively
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What is the time frame of the pre-embryo stage?
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From fertilization to two weeks
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What is the time frame of the embryo stage?
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Weeks 3 through 8
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What is the time frame of the fetus stage?
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Week 9 to birth
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Where does capacitation occur?
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In the uterus
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Why must the sperm be removed from the seminal fluid to become activated?
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There is a tripeptide fertilization promoting peptide (FPP) produced in the prostate gland of the male that prevents capacitation when it is present in high concentrations. The concentration drops when the ejaculate mixes with vaginal secretions and the low pH of the vagina, causing FPP to become less active and letting capacitation occur.
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What is capacitation of sperm?
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The activation stem needed to make the sperm fertile. Specifically, it destabilizes the acrosomal sperm head membrane to allow greater binding between the sperm and the oocyte
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What effect does hyperactivation have on the movement of sperm?
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The motility pattern becomes frenzied as it switches from linear to non-linear motion
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Where does hyperactivation of sperm occur?
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The oviduct
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Which zona protein do human sperm bind to?
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ZP3. It is species-specific
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What is the basic structure of the head of the sperm?
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From outside in, there's the plasma membrane, an outer acrosomal membrane, an inner acrosomal membrane, and the nucleus
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What occurs during the acrosomal reaction?
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The plasma membrane of the sperm and the outer acrosomal membrane of the sperm fuse and release acrosin, which allows the sperm to penetrate the zona pellucida.
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What are two purposes of the acrosomal reaction?
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1) Releases acrosin, a protease that helps the sperm eat its way through the corona radiata granulosa cells and the zona pellucida
2) Exposes the equatorial segment for fusion with the egg |
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What happens to the first few hundred sperm that get to the egg?
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They dump their acrosin to dissolve the corona radiata granulosa cells and the the zona pellucida (in that order) so later sperm can get through.
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What happens to the sperm after the sperm penetrates through the zona pellucida?
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The equatorial segment of the sperm and the plasma membrane of the egg fuse, activating the egg; the sperm is engulfed, and the sperm nucleus is decondensed
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What are three steps that activate the egg after fusion with the sperm?
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1) Intracellular [Ca2+] is increased
2) Cortical reaction 3) Completion of meiosis II and ejection of 2nd Polar Body |
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What is syngamy?
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The fusion of the sperm and oocyte pronuclei
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How long is the oocyte viable after ovulation?
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12-24 hours
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How long are sperm viable in the uterus and in the cervical mucus?
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24-72 hours and 5 days, respectively
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What structures are present the egg after 15-18 hours post-semination that show that normal fertilization has occured?
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Two polar bodies and two pronuclei in the cytoplasm
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What are male factors of infertility that can be overcome by in vitro fertilization?
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Low motility and low sperm count
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What are female factors of infertility that can be overcome by in vitro fertilization?
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Tubal dysfunction and endometriosis
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Which fertilization problems can intracytoplasmic sperm injection overcome?
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no sperm penetration
anti-sperm antibodies very low sperm count (<500,000/sample) very low sperm motility (<20% motile) Azoospermia with testicular biopsy of immature sperm |
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What proteins function in sperm penetration?
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Beta protein finds and binds to receptors on the oocyte membrane
Alpha protein causes it to insert into the membrane |
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What is the fast block to polyspermy?
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The fusion of the sperm and oocyte membranes induces Ca2+ release that depolarizes the membrane and prevents additional sperm from binding with the oocyte membrane
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What is the slow block to polyspermy?
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The increase in Ca2+ triggers fusion of the cortical granules with the plasma membrane of the egg. The zonal inhibiting proteins (ZIPs) destroy sperm receptors and cause sperm already bound to the receptors to detach
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What occurs in the egg immediately after the sperm enters?
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Meiosis II is completed, the second polar body is cast out, the ovum nucleus decondenses (forms a pronucleus), and the two pronuclei approach each other
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Where does fertilization normally occur?
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The ampulla of the Fallopian (uterine) tube
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When is the morula formed and how many cells are present at that point?
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The morula is formed after 72 hours, and it usually contains about 16 cells
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What does the pre-embryo look like by day 4 or 5?
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A blastocyst: a fluid-filled sphere with a single layer of trophoblasts, an inner cell mass, and a fluid-filled cavity
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When and where does the blastocyst normally implant?
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By day 6 in the endometrium of the uterus
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What are four events that occur during implantation?
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1) The trophoblasts adhere to the wall of the endometrium
2) The trophoblasts form two layers: the cytotrophoblast and the invasive syncytiotrophoblast 3) The implanted blastocyst is covered over by endometrial cells by the 14th day after ovulation 4) hCG is first found in maternal circulation |
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What is the function of human chorionic gonadotropin (hCG)?
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It maintains the viability of the corpus luteum, allowing the corpus luteum to continue producing estrogen and progesterone
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Between weeks 8-12, the placenta develops and then continues to perform what role?
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It produces estrogen and progesterone (as well as human placental lactogen, human chorionic thyrotropin, and relaxin), provides nutrients, and removes waste
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Why do hCG levels drop off after about week 12?
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The placenta is producing the estrogen and progesterone, so the corpus luteum no longer needs to be maintained
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Which two tissues contribute to the placenta?
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Embryonic trophoblastic tissues and maternal endometrial tissues
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Describe three features of the chorionic villi
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1) They are vascularized
2) They extend to the embryo as umbilical arteries and veins 3) They lie immersed in the maternal blood present in the lacuna |
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What does the inner cell mass first divide into?
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The epiblast and the hypoblast
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What are two functions of the amnion?
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1) Provide a buoyant environment to protect the embryo
2) Helps maintain a constant homeostatic temperature |
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What are the sources of amniotic fluid?
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Maternal blood initially, and then fetal urine
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What cells of the blastocyst form the amnion?
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The epiblast
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What cells of the blastocyst form the yolk sac?
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The hypoblast
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What are two important functions of the yolk sac?
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1) Produces early blood cells and vessels
2) Is a hang-out spot for primordial germ cells |
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Broadly, which cells mediate the hormonal communication between the fetus and the mother?
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Trophoblast cells
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How does hormonal communication between the mother and the fetus ensure that the fetus gets what it needs for growth and development?
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Hormones from the placenta shift the control of regulatory functions to the fetus to ensure optimal control of gestation
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Which proteins are needed for blastocyst implantation into the endometrial wall? Where are these proteins expressed?
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Adhesion molecules such as selectin, integrin, and trophinins. These are expressed on trophoblast cells and on the uterine epithelium.
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What kind of signalling occurs between the blastocyst and the endometrium of the uterus?
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Paracrine signaling with cross-talk
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What are the roles of progesterone during implantation?
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1) Regulates prostaglandin production to inhibit contractions of the uterine smooth muscle
2) Helps to facilitate immune tolerance, along with other factors released by the trophoblast |
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What is the purpose of the VEGF that is secreted by the trophoblast?
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Initiates angiogenesis
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Which cells form the lacunar network that contains the mother's blood?
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The syncytiotrophoblast
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Which layers of cells form the chorion (the fetal portion of the placenta)?
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The trophoblast (both cyto and syncytio) and the somatic mesoderm
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Which protein secreted by the syncytiotrophoblast maintains the corpus luteum?
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human chorionic gonadotropin (hCG)
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Decidua
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The name for the endometrium of the uterus during pregnancy. It forms the maternal part of the placenta
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Interstitial invasion
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The cytotrophic stem cells proliferate and cross into the decidua and myometrium. These form the anchoring villus
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What vessels does the maternal portion of the placenta contain?
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1) Maternal arterioles emptying into the maternal blood pools
2) Maternal venules that drain the blood pools 3) Fetal capillaries protected by a layer of trophoblast cells |
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How do syncytiotrophoblast help the fetus control the amount of blood entering the placenta?
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They invade maternal blood vessels and strip out the inner lining so that the mother no longer has control over the amount of blood going to the fetus
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What are the vessels in the umbilical cord? Which contain(s) oxygenated blood?
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Two umbilical arteries wrapped around one umbilical vein. The umbilical vein carries oxygenated blood to the fetus and the umbilical arteries carry deoxygenated blood back to the maternal blood pools.
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What type of placentation do rodents have? What are the features of blood vessels in the placenta?
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Endothelialchorial. The fetal vessels and maternal vessels are both fully formed (i.e., no disruption of the lining of the maternal vessels) and are separated by a single layer of trophoblastic cells
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What type of placentation do ruminants have? What are the features of blood vessels in the placenta?
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Epitheliochorial. The fetal vessels and maternal vessels maintain their shape and are separated by a layer of trophoblastic cells and a layer of uterine epithlium
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What type of placentation do primates have? What are the features of blood vessels in the placenta?
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Haemochorial. The fetal vessels maintain their integrity, but the maternal vessels are open to allow blood to fill the intervillus space. There is a layer of cytotrophoblastic and syncytiotrophoblatic cells between the fetal vessels and the maternal blood
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Hemochorial
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The maternal blood directly bathes the chorionic villi, and there is no mixture of fetal and maternal blood
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What is an example of an exchange that occurs across the placenta?
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The fetus will eliminate toxic substances like carbon dioxide and take in oxygen and glucose
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When and from what does the placenta develop?
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Develops about 14 days after fertilization from the fingerlike projections of cytotrophoblast cells which extend through the syncytiotrophoblasts to the maternal vasculature in the endometrium.
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Which seven hormones are secreted by the placenta?
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hCG, estrogen, progesterone, human placental lactogen (hPL, a.k.a. human chorionic somatommamotropin), ACTH-like protein, PTH-related protein, and hypothalamic-like releasing hormones
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What are the non-placental counterparts of the placental hormones?
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1) hCG = LH
2) hPL = GH, hPRL 3) ACTH-like protein =ACTH 4) PTH-related protein = PTH 5) Hypothalamic-like releasing hormones = GnRH, TRH, CRH, somatostatin |
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What are five maternal adaptations to pregnancy that ensure the fetus has what it needs to grow and develop?
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1) 30% increase in blood volume, along with an increase in RBC mass and a fall in arterial blood pressure
2) Cardiac output increases by 30% 3) Weight gain 4) Breasts enlarge two fold 5) Slight insulin resistance |
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What is the maternal-fetal food fight?
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Mother and fetus compete for the glucose in the blood
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How does hPL contribute to the maternal-fetal food fight?
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hPL acts on the mother's prolactin receptors to decrease sensitivity to insulin so that blood sugar remains high for longer after a meal
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What causes gestational diabetes?
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The mother is not able to mount a proper insulin response against fetal manipulation of insulin resistance
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What are three risks for the mother and infant that result from gestational diabetes?
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1) Macrosomia and birth difficulties
2) Metabolic imbalance in the neonate 3) Increased risk of type II diabetes for mother and child, and increased risk of obesity in the child |
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What can cure gestational diabetes?
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The birth of the baby
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What is the incidence of gestational diabetes?
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It affects about 10% of pregnancies
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How does the fetus remodel maternal spiral arteries?
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Trophoblast cells invade the artery, decrease the spirality to create a high-flow, low resistance zone, and replace the smooth muscle and endothelium of the artery with trophoblast cells
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How does the fetus increase the blood supply to the placenta?
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It increases maternal blood pressure.
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Pre-eclampsia
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Pregnancy-induced hypertension
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What causes pre-eclampsia?
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Factors released by the placenta that increase blood pressure. Usually due to inadequate placental invasion and remodeling of the spiral arteries
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What reduces the risk for pre-eclampsia?
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High levels of paternal antigens, administered via sex
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How does one cure pre-eclampsia?
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Birth
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What are the risks for the fetus in pre-eclampsia?
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Prematurity, still-birth, and growth restriction
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What is the result of a failure of deep implantation of the blastocyst into the uterine tissue?
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Miscarriage
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What is the result of a failure of modification of the spiral arteries by the end of the first trimester?
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Increases risk of pre-eclampsia
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What muscle drives human birth?
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The myometrium of the uterus
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What are uterotrophins?
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Hormones that activate uterine activity (such as estrogen and progesterone).
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Which hormone is most active in keeping the uterus quiescent during pregnancy?
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Progesterone
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What is the effect of progesterone on the uterus?
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It decreases the number of gap junctions between smooth muscle cells and down-regulates expression of ion channels in order to suppress contractions
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What is the effect of estrogen on the uterus as it transitions from quiescent to laboring?
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It increases the number of gap junctions and up-regulates ion channels, stimulatory uterotonin production, and stimulatory uterotonin receptors
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Uterotonins
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Hormones that cause changes in the way the uterus contracts (i.e., oxytocin and prostaglandin)
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What is the effect of oxytocin on pregnancy?
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Maintains contractions of the uterus. Note that it doesn't initiate the contractions; instead, it plays a role as part of the positive feedback loop in later stages of labor
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What induces oxytocin release?
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Stretching of the cervix
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What is the positive feedback loop that induces the amplification of labor?
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The baby's head stretches the cervix,which excites fundic contraction of the uterus, which moves the baby toward the cervix and stretches it more, and so on.
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Which hormones are secreted by the fetus to induce labor?
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Oxytocin, cortisol, and prostaglandins
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What is the role of prostaglandin in labor?
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It induces uterine contractions, promotes formation of gap junctions in the uterine wall, and causes dilation, softening, and thinning of the uterus during early labor.
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What is the effect of administering prostaglandin at any stage of gestation?
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It will induce labor
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What is the range in size for cervical dilation?
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Cervix dilation can range from 0 cm (closed) to 10 cm (fully dilated).
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What is cervical effacement and how is it measured?
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The shortening of the cervix: it pulls up into the uterus and becomes part of the lower uterine wall. It is measured as a percent, so it can range from 0-100% effaced.
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What cervical dilation and effacement are needed for labor to be considered active?
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>4 cm dilated and > 80% effaced
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What are the three stages of labor?
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1) First stage is from labor onset to full dilation. This stage can last from 8 to 24 hours or longer in the first pregnancy, and is usually shorter in later pregnancies.
2) Second stage is from full dilation to delivery of the baby. This stage can last from 1 minute to 30 minutes or more. 3) Third stage is from delivery of the baby to delivery of the placenta. |
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How does hormonal control of labor in humans differ from hormonal control in sheep, rats, and cows?
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Sheep, rats, and cows have a systematic withdrawal of progesterone and estrogen activation.
In humans, the ability to respond to the already-present levels of estrogen is amplified and the ability to respond to progesterone is inhibited by a differential expression of receptors. This explains why adding estrogen doesn't induce parturition and why adding progesterone doesn't inhibit parturition in humans. |
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What are two traits that humans have developed that make childbirth more difficult for human females than it is for our closest primate relatives?
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Bipedalism and encephalization (increasing brain size)
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In order to maintain pregnancy, which hormone is the uterus most responsive to?
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Progesterone
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What hormonal switch must occur on the part of the uterus to induce partuition?
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The myometrium must become refractory to progesterone and responsive to estrogen.
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What are six reasons for performing prenatal screening?
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1) Helps in managing final weeks of pregnancy
2) Helps determine the outcome of pregnancy 3) Helps plan for possible complications with birth progress 4) Helps plan for potential problems that may occur in the newborn infant 5) Helps parents decide if they want to continue the pregnancy 6) Helps find potential problems to consider for future pregnancies |
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Which hormone released by trophoblast cells can be measured early on to detect early pregnancy?
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hCG
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What is one possible cause of hCG levels being lower than normal?
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This could be a sign of ectopic pregnancy or threatened abortion
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What chromosomal abnormality does elevated hCG coupled with decreased AFP, elevated inhibin A, and low estriol indicate?
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Trisomy 21
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What do very high levels of hCG indicate? What about high levels of hCG along with absence of a fetus on ultrasound?
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Trophoblastic disease (molar pregnancy)
Hydatidiform mole |
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Which hormone can be measured to assess successful treatment of a molar pregnancy?
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hCG
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What is the pattern of maternal hCG secretion over the course of pregnancy?
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hCG secretion begins at 8-9 days after fertilization. Levels rise sharply and peak at 8-12 weeks, then drop by 16-20 weeks and remain at the same level for the remainder of the pregnancy. This drop occurs because the placenta takes over production of progesterone from the placenta.
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How is estriol produced in pregnancy?
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DHEA-S is produced by the adrenal cortex of the fetus. This is converted to 16-OH-DHEA-S by the fetal liver. 16-OH-DHEA-S is then converted by the placenta to estriol.
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What do maternal estriol levels tell you about the fetus?
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It tells you the activity of the fetal HPA axis and the health of the fetal liver
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What is one possible cause of elevated estriol levels?
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Congenital adrenal hyperplasia caused by 17-hydroxylase deficiency.
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What conditions can create false positives and false negatives in estriol testing for fetal distress?
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Pre-eclampsia, anemia, and impaired kidney function
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What are two major differences between adult and fetal production of steroids in the adrenal cortex?
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1) The fetus cannot convert progesterone to 17-OH-progesterone (so cannot divert precursors from the cortisol pathway to the aldosterone pathway)
2) The fetus cannot convert DHEA to androstendione or make the adult sex steroids |
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How do maternal precursors and the placenta interact to produce progesterone?
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Cholesterol from the mother is converted to pregnenolone in the placenta. It is then converted to progesterone and returned to the mother to maintain pregnancy.
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How are estrone and estradiol produced during pregnancy?
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1) Cholesterol is converted to pregnenolone in the placenta
2) Pregnenolone is sulfated in the fetus 3) Pregnenolone sulfate is converted to 17-OH-pregnenolone 4) 17-OH-pregnenolone is converted to DHEA-S, which then returns to the placenta and is desulfated to DHEA 5) DHEA is converted to estrione and estradiol and returned to the mother |
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What is the function of Pregnancy Associated Plasma Protein A (PAPP-A)?
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It is a protease that releases IGF from its binding proteins so it can bind to its receptors and fulfill its role in trophoblast invasion and formation of the placenta
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What can result from low levels of PAPP-A?
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Low-for-gestational-age birth weight babies
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What do high levels of Alpha Fetal Protein (AFP) indicate?
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A neural tube defect in the fetus: failure in closure of part of the tube
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What are the signs and symptoms of pregnancy?
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Primary: amenorrhea
Nausea, vomiting, breast enlargement/tenderness, fatigue, increased urination (without dysuria), bloating, cramping, constipation, heartburn, congestion, dyspnea, food cravings/aversion, mood swings, lightheadedness, increased skin pigmentation |
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Which hormone levels are increased in pregnancy?
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hCG (1st trimester)
Progesterone, Estrogen (Estriol), Inhibin A GnRH ACTH Prolactin Oxytocin Calcitonin Thyroglobin Binding Protein Total T3/T4 Renin/Aldosterone Cortisol Androgens hPL insulin |
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Which hormone levels stay the same in pregnancy
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ADH/Vasopressin
GHRH TRH TSH (initial decrease, but stable after) Free T3/T4 |
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Which hormone levels decrease in pregnancy?
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Somatastatin
Growth Hormone FSH/LH |
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What physical changes in the mother occur during pregnancy?
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Incr Water retention
increased urination 2x Breast increase Weight Gain Polyphagia GI changes nausea/vomitting diarrhea/constipation Sleep problems Incr insulin resistance Incr Blood Volume (2 L) Incr Cardiac Output (30%) Decr BP Heart Incr Blood Volume (2 L) Incr Cardiac Output (30%) Decr BP Blood is in “hypercoaguable state” Decr P(O2), P(CO2) Incr Tidal Volume Diaphragm displaces Up, Thorax moves out |
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What changes occur in the source of energy for the mother?
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Directed toward supplying glucose and amino acids to the fetus while providing extra FFAs,
ketones, and glycerol as sources of maternal fuel. |
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Which eight proteins inhibit the onset of uterine contractions (they maintain the pregnancy)?
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Progesterone, prostacyclin, relaxin, nitric oxide, PTH-rP, CRH, and hPL
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Which is the glucose transporter of trophoblast cells?
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GLUT-1
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Which fetal anomalies are associated with abnormal glucose metabolism in the mother?
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Renal agenesis/caudal dysgenesis syndrome, congenital heart defects (such as tetralogy of Fallot), neural tube defects (such as anencephaly, spina bifida, encephalocele, and hydrocephaly), increased risk of limb deficiencies, spontaneous abortion second to hyperglycemia, maternal vascular disease, and immunologic factors, and macrosomia
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What are five factors that affect fetal growth?
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1) Glucocorticoids and insulin
2) IGF 1 & 2 3) Epidermal Growth Factors 4) Thyroid Hormones 5) Peptide hormones secreted by the placenta |
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What are risks caused by diabetes mellitus to the pregnant mother?
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Hypertension/preeclampsia
CardioVas Disease Peripheral and autonomic neuropathy Infection- UTI which can increase risk of preterm labor or diabetic ketoacidosis Diabetic retinopathy- related to duration of DM and degree of glycemic control |
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What is gestational diabetes?
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Condition of elevated blood sugar levels that starts during
pregnancy. (typically halfway) |
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How do gestational diabetes, DM1, and DM2 compare?
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GDM more similar to DM2 than DM1 because it is not an autoimmune destruction of
beta cells, it results from insulin reisistance. Although genetics and being overweight puts you at greater risk, it is not the cause of GDM (unlike DM2) |
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What are risk factors for developing gestational diabetes?
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Family History
Overweight pre pregnancy Age Previous birth > 9lbs Past glucose intolerance Use glucocorticoids Hypertension |
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What are four tests used in the first trimester for prenatal screening?
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Ultrasound tests: Nuchal translucency and Crown Rump Length
Serum tests: PAPP-A and beta-hCG |
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Why do prenatal screening tests measure beta-hCG specifically?
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The beta subunit confers specificity on hCG. The alpha subunit in hCG is nearly identical to the alpha subunit in TSH, LH, and FSH.
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What is nuchal translucency and what does it tell you?
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fluid-filled fold incr at back of neck
⁃ etiology: abnormal lymphatic development, cardiac function, collagen, anemia ⁃ incr risk for Down syndrome |
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What is measured in the quad test performed in the second trimester?
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AFP - made by fetal liver, strongest assoc w poor outcomes, detects NTD
hCG uE3- Estriol ⁃ made by fetus/placental unit, low values associated with intrauterine growth restriction⁃ Inhibin A ⁃ produced by corpus luteum, decidua, placenta |
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What is needed for fertility?
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Healthy sperm
Intact male pathway Intact female pathway Ovulation (Healthy egg) Fertilization Implantation (Healthy endometrium) |
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Which screening tasks are performed at the first prenatal visit?
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Family history, Basic Physical, Routine tests: Rhesus type, Hematocrit,
cervical cancer screen, Rubella & Varicella, urine culture, STI testing ⁃ At risk: Thyroid function, DM2, other STIs ⁃ Inherited disorders ⁃ CF ⁃ Fragile X ⁃ A-J Recessive Disorders ⁃ Spinal Muscular atrophy |
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Which prenatal tests are performed between 11 and 14 weeks?
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Down test: NT, hCG, PAPP-A
⁃ could have CVS |
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Which prenatal tests are performed between 15 and 22 weeks?
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NT screening, Down quad test
⁃ could have amnio ⁃ ultrasound @ 18 wks to check for congenital anomalies |
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Which prenatal tests are performed between 24 and 28 weeks?
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GDM screen
⁃ hemoglobin/hematocrit check |
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Which prenatal tests are performed between 28 and 36 weeks?
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Ultrasound
⁃ fetus should be flipped over |
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What are four methods by which contraception can work?
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1) Suppression of ovulation
2) Reduce sperm transport in upper genital tract 3) Change endometrium to make implantation less likely 4) Thicken cervical mucus to prevent sperm penetration |
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What are some advantages and disadvantages of Chorionic Villus Sampling?
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Chorionic Villus Sampling
⁃ small sample of placenta obtained for cytogenic analysis ⁃ first trimester, after 10 weeks ⁃ transcervical, transabdominal ⁃ Advanates ⁃ can be performed earlier ⁃ more time to consider options ⁃ more time for counseling ⁃ earlier abortions are safer ⁃ Low false negative rate (but not as low as amnio) ⁃ Disadvantages ⁃ correlated w incr risk of preeclampsia ⁃ Fetomaternal hemorrhage ⁃ cannot detect NTD or severity of disorder ⁃ need larger sample (compared w amnio) ⁃ Greater need for follow up ⁃ abnormal mosaicism |
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What are some advantages and disadvantages of Amniocenteisis?
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amniocytes shed by fetus are collected from amniotic fluid and
cultured for cytogenic analysis ⁃ performed after 14 weeks/ 2nd trimester (earlier at higher risk) ⁃ ⁃ ADV ⁃ risk of maternal/fetal injury is very small ⁃ no limitations of maternal activity necessary ⁃ DISADV ⁃ risks: ⁃ membrane rupture-- amniotic fluid ⁃ risk of direct/indirect fetal injury ⁃ fetal loss ⁃ amniocytes might not grow in culture |
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What are some advantages and disadvantages of non-invasive prenatal testing?
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cell-free fetal DNA in maternal serum
⁃ free DNA fragments sequenced and compared ⁃ 10-23 weeks ⁃ ADV ⁃ high sensitivity and specificity ⁃ noninvasive ⁃ DISADV ⁃ fetal DNA/RNA not always distinguishable from maternal ⁃ CVS/ amnio might be needed for confirmation of + result ⁃ results take 8-10 days |
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What are the two main causes of Down syndrome?
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1) de novo aneuploidy (Trisomy 21)- has 47 chromosomes
2) Robertsonian translocation: karyotype shows 46 chromosomes, but one contains double the genetic information (trisomic for 21q) ⁃ 46XY, rob (14;21)(q10;q10), +21 ⁃ der (14;21) |
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What are symptoms of Down syndrome?
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Growth
retardation ⁃ varying degree of mental retardation ⁃ craniofacial abnormalities: upward-‐slanting eyes, epicanthal folds (eyes), =lat/broad faces, small ears, protruding tongue ⁃ broad hand with single transverse crease ⁃ cardiac abnormalities ⁃ hypotonia ⁃ Chromosome aneuploidy causes multisystem malformation by the direct or indirect effects of overexpression of the genes on chromosome 21. ⁃ Gene expression studies have shown that a signi=icant proportion of genes on chrom 21 are overexpressed in brain and heart samples. |
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What does progestin do in combination contraceptives?
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Ovulation inhibition, ovarian inhibition, thickening of cervical mucus, endometrial atrophy, and cycle control
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What does estrogen do in combination contraceptives?
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Follicle inhibition, ovarian inhibition, thinning of cervical mucus, endometrial proliferation, and cycle control
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What are three combination contraceptives?
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Combination oral contraceptives, transdermal patch, and vaginal ring
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What are four progestin-only contraceptives?
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Progestin-only oral contraceptives, vaginal ring, quarterly injectable, levonorgestrel intrauterine system
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What are four non-hormonal methods of contraception?
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Copper IUD, barrier methods, withdrawal, and natural family planning
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Which are forms of male contraception?
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Vasectomy, condoms, and withdrawl
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What is sequential screening?
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It combines risks of first check and quad screen to provide more valuable detection of fetal anomalies
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Describe hCG
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Secreted by trophoblasts
Peaks around 10 weeks, then drops and plateaus around 20 weeks Maintains corpus luteum (progesterone) Stimulates adrenal and placental steroidogenesis Immunosuppresive Thyrotrophic activity |
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Describe progesterone in pregnancy
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Corpus luteum, then placenta
Tubal motility Inhibits T lymphocytes Uterine vasculature Uterine relaxation, inhibits prostaglandins Stimulates breast development |
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Describe estrogen in pregnancy
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Estriol, estrone made by placenta after 6 weeks
Secreted into maternal circulation Augment uterine blood flow Regulates placental steroidogenesis Increases uterine myometrial irritability and contractility, leading to labor |
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What is the function of motilin in pregnancy?
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Decreases in pregnancy
Smooth muscle stimulant Combined with progesterone effect Constipation, slower stomach emptying Nausea and vomiting |
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What is the function of prolactin in pregnancy (and afterwards)?
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Placental prolactin regulates electrolyte flux across the membranes
Breast milk production |
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What is the role of cortisol in pregnancy?
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Placental ACTH secretion
CRH—secreted by placenta Secreted by decidual tissue—immune regulation |
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What effect does pregnancy have on renin and angiotensin?
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Renin rises to 5-10 times normal
Angiotensinogen and angiotensin levels rise Increased Aldosterone production Rises, prevents sodium diuresis in spite of the increased GFR |
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What are four ways to induce menstruation with contraceptives?
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Estrogen Breakthrough Bleeding
Estrogen Withdrawal Bleeding Progestin Breakthrough Bleeding Progesterone Withdrawal |
