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65 Cards in this Set
- Front
- Back
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where do primordial germ cells originate from?
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wall of yolk sac, and then migrate into gonad region
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what are the different stages of female gametogenesis and when do they occur?
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primary germ cell (46, 2N)--> primordial oognonia (46, 2N) --> primary oocytes (46, 4N) - where they remain arrested until puberty
--> primary oocyte completes meiosis 1 and forms a secondary oocyte (23, 2N) + 1st polar body --> secondary oocyte is arrested in metaphase II until fertilization at fertilization: secondary oocyte completes meiosis II and forms a mature oocyte (23,1N) + 2nd polar body |
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what are the different stages of male gametogenesis and when do they occur?
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primordial germ cells (46, 2N) --> type A spermatogonia (46, 2N, can undergo mitosis and provide a continuous supply of sperm throughout lifetime)
some type A --> type B spermatogonia (46, 2N), which enter meiosis I --> primary spermatocytes (46, 4N) --> secondary spermatocytes (23, 2N) --> 4 spermatids (23, 1N) |
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describe maturation process of spermatids
how long does it take? |
spermatids --> spermatozoa
condensation of nucleus, formation of acrosome, formation of head, neck, adn tail) takes 64 days |
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what is capacitation?
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sperm can't fertilize an egg until they go through this process
unmasking of sperm glycosyltransferase and removal of proteins that coat the surface of the sperm |
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what are offspring at risk for if there is advanced Paternal age?
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achondroplasia (retaded bone growth)
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how does hte "morning after" pill work?
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high doses of steroids that disrupt the endometrium so that implantation can't occur
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what precaution must be taken if someone takes the mornign after pill?
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steroids --> teratogenicity
if the pill doesn't work, therapeutic abortion recommended |
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what can be used to treat anovulatory cycle?
MOA |
clomiphene citrate
it competes with estrogen at binding sites at the adenohypophysis, so it causes an increase in FSH/LH by suppressing the normal negative feedback |
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where does fertilization occur?
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in the ampulla of the uterine tube
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what are the steps of fertilization?
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acrosomal reaction so sperm can penetrate the zona pellucida
--> cortical reaction so egg is not fertilized by more than 1 sperm sperm and secondary oocyte membranes fuse adn sperm contents enter the cytoplasm of the egg sprem genetic material --> male pronucleus and tail/mitochondria degenerate secondary oocyte completes MII and forms a mature ovum. nucleus of ovum = female pronucleus pronuclei fuse --> zygote! |
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what stages does the zygote go through following fertilization?
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series of mitotic divisions
blastula (2 cells, then 4 cells, 8, 16) each cell is called a blastomere --> morula (32 cells) --> blastocyst |
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what is the structure of the morula?
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inner cell mass and outer cell mass
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at what stage is the zygote totipotent?
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until the 8 cell stage
each blastomere can form an entire embryo by itself |
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how does the blastocyst form?
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fluid is secreted within the morula, forming the blastocyst cavity
the outer cell mass becomes part of the placenta (trophoblast) and the inner cell mass becomes teh embryo |
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what does the trophoblast differentiate into?
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syncytiotrophoblast
cytotrophoblast |
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what must happen in order for implantation to occur?
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zona pellucida degeneration
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where does the blastocyst implant?
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within the posterior superior wall of the uterus, unless it's during the seretory phase of mentrual cycle, then it will implant in teh functional layer of the endometrium
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describe the process of ectopic pregnancy
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blastocyst implants in uterine tube d/t delayed transport `
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what is the most common site for ectopic pregnance?
most common site for ectopic abdominal pregnancy |
uterine tube
rectouterine pouch (pouch of douglass) |
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what predisposes ppl to ectopic pregnancy
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endometriosis
PID |
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cause of dizygotc tiwns?
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fertilization of 2 different eggs with 2 different sperm
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cause of monozygotic twins
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fertilization of 1 egg w 1 sperm
division of inner cell mass of blastocyst (embryoblast) in same placenta |
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cause of conjoined twins
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embryoblast doesnt' entirely split
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when does the embryoblast become bilaminar?
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during week 2
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what are the 2 layers the embryoblast divides into?
what does each become? |
epiblast (--> amniotic sac)
hypoblast (--> yolk sac) |
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what is the future site of the mouth at week 2?
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prochordal plate (the fusion of the epiblast and hypoblast cells)
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describe the growth of syncytiotrophoblast?
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continues growth into endometrium and makes contact wiht endometrial BV and glands
it doesn't divide mitotically |
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describe the growth of the cytotrophoblast?
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primary chorionic villi protrude into syncytiotrophoblast
divides mitotically |
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what is the extraembryonic mesoderm?
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new layer of cells derived from epiblast
--> connecting stalk and covers amnion |
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what forms the connecting stalk?
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extraembryonic somatic mesoderm that lines the cytotrophoblast
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what is the wall of the chorionic cavity called?
what does it consist of? |
chorion
extraembryonic somatic mesoderm cytotrophoblast syncytiotrophoblast |
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what are the different types of extraembryonic mesoderm?
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extraembryonic somatic mesoderm (--> connecting stalk)
extraembryonic visceral mesoderm (covers yolk sac) |
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where is hCG produced? what does hCG do?
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syncytiotrophoblast
stimulates production of corpus luteum, which is necessary for progesterone production during the first 8 weeks of pregnancy |
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describe the source of progesterone in pregnancy?
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made by the syncytiotrophoblast for the first 8 weeks, and then made by teh placenta for the remainder of the pregnancy
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when can hCG be detected?
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day 8 in blood and day 10 in urine
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how long is hCG detectable for?
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throughout pregnancy
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pathogenesis of hydatidiform mole?
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death of embryo, followed by hyperplastic proliferation of trophoblast --> vesicular or polycystic mass
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what % of hydatidiform moles develops into gestational trophoblastic neoplasia?
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3-5%
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whhat adult cancer is associated with high CEA?
hihg AFP? |
CRC
hepatoma, germ cell tumors |
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another name for RU-486?
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mifepristone
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MOA of RU 486
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if implantation of conceptus has occurred, conceptus will be sloughed off along with endometrium
it blocks progesterone receptor |
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when does an embryo have a distinct human appearance?
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by 8 weeks
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how is cranio-caudal direction controlled?
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Hox complex of genes
eaach contains 180 base pairs that encode 60AA long region that binds to DNA |
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what is gastrulation?
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developing 3 germ layers
--> trilaminar embryonic disk (endoderm, ectoderm, mesoderm) |
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what is the first indication of gastrulation?
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formation of primitive streak within epiblast
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what do the neuroectoderm and neural crest cells arise from?
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ectoderm
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what are the different types of mesoderm that arise?
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paraxial mesoderm
intermediate mesoderm lateral mesoderm |
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what is sacrococcygeal teratoma?
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remnant of primitive streak (which usually degenerates and disappears)
can contain bone, nerve, and hair because primitive streak is pluripotent |
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what is chordoma?
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remnant of notocord, found either intracranially or in sacral region
occurs in men over 50 can be benign or malignant |
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where is the notocord?
what does it do? |
mesoderm located between primitive node and prochordal plate
induces the formation of the neural tube |
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what are the components of the primitive streak?
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primitive groove, pit and node
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describe migration of epiblast cells
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ectoderm
although, some epiblast cells displace the hypoblast cells --> endoderm and others tay midline and form mesoderm |
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what is caudal dysplasia?
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constellation of syndromes ranging from minor lesions of lower vert --> complete fusion of lower limbs
caused by abnormal gastrulation (migration of mesoderm is disrupted) |
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what are the cranial anomolies associated with caudal dysplasia?
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VATER
vertebral defects anal atresia TE fistula renal defects or... VACTERL VATER + CV defects and upper limb defects |
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what embryonic event corresponds to 1st missed menstrual period?
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week 3 of embryonic development
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which period of embryonic development is most susceptable to teratogens?
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embryonic period (3-8 weeks)
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what are the components of the placenta and where do they originate from?
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maternal component (portion of the endometrium called decidua basalis)
fetal component (tertiary chorionic villi, collectively called the villous chorion) |
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what does the maternal surface of the placenta look like in the afterbirth?
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15-20 cotyledons that make it look cobblestoned
surface is dark red and oozes blood after birth (from torn maternal BV) |
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what does fetal surface of placenta look like in afterbirth?
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chorionic BV, appearing smooth and shiny b/c of amnion covering
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what is velamentous placenta?
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occurs when umbilical vessels abnormally travel through amniochorionic membrane before reaching placenta proper
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what is vasa previa
potential complication? |
if mubilical vesssels cross internal os
one of hte BV could rupture --> fetus will bleed to death |
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what is placenta previa?
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placenta is in lower part of uterus, covering internal os (instead of posterior superior wall of uterus)
uterine bv rupture in later part of pregnancy as uterus dilates mother can bleed to death and fetus will have compromised blood supply |
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clinical presentation of placenta previa?
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bright red vaginal bleeding
deliver by c-section b/c placenta blocks cervical opening |
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why does the mom not reject the placenta?
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PGE2 inhibits t cells
also, no MHC on sycytiotrophoblast |
