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7 Cards in this Set
- Front
- Back
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Uterine-Placental Connection
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Long Spiraly uterine arteries (rupture in uterus when low progesterone b/f menses) come in contact w/ placenta via placental villi which line uterus septa: border outfoldings; villi come in contact w/capillararies (arterial end/red above venous end/blue); all capallaries attached to amniotic cord, containing 2 intertwined umbilical arteries that go to fetus; diffusion-limited O2 exchange
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Fetal Hb content
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curve shifted left & higher than maternal hb curve on PO2 v. %hb sat w/O2 graph
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Fetal Circulation
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amnion contains intertwined umbilical a. (carries deO2 blood) & umbilical v. (carries O2 blood); umbilical v-> liver -(via ductus venosus)-> IVC -> RA (via foramen ovale) -> LA, LV, Aorta, body; Umbilical a -> internal iliac a. -> pulmonary a. -(Ductus Arteriosus) -> aorta-> body
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Parturition Changes
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placenta removal=removal of huge parallel circuit (umbilical a. & v. paths) => doubles systemic circuit resistance => decreases IVC pressure & RA pressure (less R to L flow via foramen ovale) & increases LV pressure = increased LA pressure; LA pres> RA pres so foramen ovale closes (adults)
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Baby's 1st breath
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decreases pulmonary circuit resistance; must breathe since placenta is cut off (also, its PO2 low PCO2 high due to tissues using oxygen) & new world environment is shocking so lets out a gasp (diving reflex: hold your breath under water; when babies head emerges from amniotic fluid, gasps); intrathoracic p decreases w/80 cm-> establishes air-liquid interface & negative/ less-than-atmospheric air pressure (lungs collapsed, chest expanded)-> circ. changes
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Circulation changes at 1st Breath
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L to R Shunt: high Aortic P causes blood 2 flow from aorta -> pulmonary artery (low lung Resistance: lowers RV+RA pressure); Right Heart Pressure now less than Left Heart Pressure so no R to L shunt; High flow/low resistance circulation + high alveoli O2ated/ventilated ridding hypoxic vasoconstriction (seen in fetus: high resistance, low flow to lungs); alveolar liquid-air interface establishes lung recoil
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Ductus Arteriosus
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behaves as peripheral systemical vessel, constricts itself in response to high PO2; reversed direction of flow through ductus arteriosus after birth (instead of pulm to aorta shunt; aorta to pulm shunt b/c of pressure changes); if open: LV fails, pulmonary to aortic flow causes cyanosis + dyspnea; prostacyclins open ductus arteriosus; indomethicin closes a patent ductus arteriosus (closure causes high RV afterload)
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