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28 Cards in this Set
- Front
- Back
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Placenta overview...
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1) Fetomaternal organ discoid shape —> 2) 2 parts = fetal and maternal --> 3) fetal develops from chorionic sac (smooth chorion and villous chorion/frondosum) —> 4) materal develops from endometrium (decidua basalis and placental septa) —> 5) functions are protection, nutrition, respiration, exretion and hormone production —> 6) the decidua is the functional layer of the endometrium with 3 regions = decidua basalis, capsularis, and parietalis.
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Hormone production related to the placenta...
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1) Human chorionic gonadotropin (hCG) —> 2) Human chorionic somatomammotropin (hCS) —> 3) Human chorionic thyrotropin (hCT) —> 4) Human chorionic corticotropin (hCACTH) —> and 5) Progesterone
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Umbilical cord...
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1) Short cord could be ruptured or cause difficulties during delivery —> 2) vessels are normally 2 arteries and 1 vein —> 3) if only one artery then possible cardiovascular or renal anomalies —> 4) umbilical vessels are longer than length of the cord —> 5) twisting of the vessels may produce knots (fetal death by anoxia) —> 6) may also twist around neck
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The synctiotrophoblast makes proteolytic enzymes as well as..
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hCG
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Formation of amniotic cavit review (days 8-9)...
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1) cavity in embryoblast later turns into amniotic cavity —> 2) embryonic disc forms with epiblast (floor of amniotic cavity from which amnioblasts leave epiblast to form amnion) and with hypoblast (forms roof of ecocolomic cavity that's continuous with cells that form the exocolomic membrane) —> 3) and the extraembryonic mesoderm is formed by outer layer of cells of primary umbilical vesicle and is surrounded by amnion and primary umbilical vesicle
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Formation of lacuna & colomic spaces review (days 10-12)...
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1) Lacunae are fluid-filled cavs in syncytios with maternal blood and uterine gland secretions/debris (acts as beginning of uteroplacental circulation) —> 2) extraembryonic colomic spaces are cavities that appear in extraembryonic mesoderm
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Formation of extraembryonic colom and chorion review (days 13-14)....
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1) Extraembryonic colom = large fluid filled cav that surrounds amnion and umbilical vesicle —> 2) formed by fusion of extraembryonic and colomic spaces —> 3) becomes chorionic cavity —> 4) 2 layers of extraembryonic mesoderm form = somatic (to line trophoblast and form chorion and also to cover amnion and form connecting stalk) —> 5) and splanchnic (to surround umbilical vesicle and form secondary umbilical vesicle where the primary pinches off)
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Development of chorionic villi...
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1) Primary chorionic villi = 1st stage in development of placental chorionic villi —> 2) cytotrophoblasts proliferate and grow into syncytios to form cytotrophoblastic core —> 3) secondary villi = mesenchyme core that covers entire surface of chorionic sac —> 4) tertiary villi = capillaries are visible and fuse to form arteriocapillary networks that connect to embryonic vessels —> 5) cytotrophoblast shell has its cells proliferate and extend into syncytio and surrounds chorionic sac and attach it to endometrium —> 6) intervillous space = maternal blood
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Placental membrane...
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Until 20th week there are 4 layers: 1) synctiotrophoblast, 2) cytotrophoblast, 3) connective tissue core of villus, and 4) fetal capillary endothelium —> after 20th week the cytolayer degenerates
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Amnion...
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Fluid-filled membranous amniotic sac
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Source of amniotic fluid...
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1) Amnion cells, 2) maternal blood and interstital fluid, 3) fetal meconium & urine, 4) skin, 5) secretions from GI & resp tracts
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Composition of amniotic fluid...
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Mostly water w some protein, glucose, vitamins, antigens and maternal antibodies (IgG)
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Circulation of amniotic fluid...
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1) 30mL @ 10 weeks, 2) 350mL @ 20 weeks, and 3) 1000mL @ 37 weeks —> 4) the fluid changes every 3 hours
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Functions of amnion/fluid...
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1) Cushion embryo —> 2) maintain constant temp —> 3) freedom of movement —> 4) symmetrical growth —> 5) lung development —> 6) barrier to infection —> 7) prevent adherence of amnion to embryo
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Continued development of amnion/fluid...
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1) Embryo growth —> 2) fluid volume increases —> 3) amnion fuses w chorion wall and chorionic cavity is obliterated —> 4) fetus floats in amnion fluid w cord attached to placenta
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Layers of decidua fuse...
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Decidua capsularis and parietalis —> uterine cavity obliterated
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Extraembryonic membranes fuse...
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1) Amnion and chorion —> 2) formation of amniochorionic membrane which ruptures during child birth —> 3) chorionic cavity obliterated
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Amniocentesis...
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Fluid drawn after 14th week 200mL
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a-fetoprotein...
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1) Found in fetal serum —> 2) elevated levels in amniotic fluid —> 3) possible neural tube/body wall defects
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Oligohydramnios...
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1) Low volume < 500mL at 32-36 weeks (not enough) —> 2) due to preterm rupture of amniochorionic membrane OR urinary system anomalies (like bilateral renal agenesis) OR placental insufficiencies (decreased blood circulation) —> 3) complications include lung hypoplasa and facial/limb deformities due to fetal compression by uterine wall
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Polyhydramnios...
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1) High volume >2000mL 3rd trimester (too much) —> 2) due to idiopathic (mostly), maternal (multiple pregnancies or diabetes) OR fetal (digestive system anomalies like eso atresia or CNS anomalies like merocerphaly or anencephaly) —> 3) complications include preterm labor and premature rupture of amniochorionic membrane
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Amniotic band syndrome...
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1) Rupture of amniotic sac —> 2) tears in amnion results in amniotic bands —> 3) bands encircle parts of developing fetus and causes amputations, ring constrictions and craniofacial deformations —> 4) causes are unknown but may include intrauterine trauma
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Yolk sac significance...
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Vasculogenesis —> blood vessels form 3rd week in extraembryonic mesoderm of umbilical vesicle —> progenitor cells
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Progentior cells in yolk sac...
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Originate in wall of umbilical vesicle and migrate to gonadal ridges in 5th week
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Yolk sac and primitive gut...
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Yolk sac forms primtive gut @ 4th week —> head and tail folds along with lateral folds
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Allantois...
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Comes from yolk sac as diverticulum —> finger projection fo sac into connecting stalk that shows up 3rd week
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Significance of Allantois...
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Progenitor cells —> vasculogenesiss (umbilical vein and arteries) and urinary bladder development = involutes to form the urachus & after birth becomes median umbilical ligament
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Allantois anomalies...
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1) urachal cyst —> part of allantois fails to die and may result in cyst —> 2) urachal sinus = part of allantois doesn't obliterate and results in OPENING @ umbilicus —> 3) Urachal fistula = entire allantois remains patent = bladder communicates w exterior
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