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10 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Functions of the Placenta
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Respiration-exchanges maternal oxygen with fetal carbon dioxide
Nutrition-provides nutrients from mother Endocrine-critical in hormone production Excretion-eliminates fetal waste products Protection-prevents passage of some microorganisms and allows passage of protective antibodies |
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Placental transfer
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Simple diffusion-oxygen, carbon dioxide and water
Facilitated diffusion-glucose, some electrolytes Active transport-some hormones, iron Pinocytosis-immunoglobulins |
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Placental hormones
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Steroid hormones:
Progesterone Estrogen (Estriol) Human chorionic gonadotropin (hCG) Human chorionic somatotropin (hCS) Human placental lactogen (hPL) Human chorionic thyrotropin (hCT) Human chorionic corticotropin (hCACTH) When does progesterone get secreted by the placenta? |
initially, C. luteum produces progesterone for 2 weeks post ovulation, but then the placenta produces Progesterone 2 weeks after to maintain the pregnancy after the C. luteum dies out
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Parts of the Placenta
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Fetal: chorionic villi
Maternal: decidua basalis |
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Week 2 Events
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Outer cell mass (cytiotropholasts, syncitiotrophoblasts) invade decida, produce hCG
Chorionic villi formed How does the early uteroplacental circulation form? |
Chorionic villi form, diffusion from maternal capillaries
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List the different chorionic villi and what makes them different
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Primary: cytotrophoblast core, syncytiotrophoblastic shell
Secondary: Syncytiotrophoblastic shell, Cytotrophoblastic layer, Mesenchymal core Tertiary: Syncytiotrophoblastic shell, Cytotrophoblastic layer, Mesenchymal core, Fetal capillaries Where do these villi persist/degenerate? |
Degenerate over chorion laevae (smooth chorion)
Develop into placenta over chorion frondosum (villus chorion) |
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Name of cavities in which maternal blood from spiral arteries comes in contact with fetal villi
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cotyledons
(from greek: Kotuledons; cup-shaped cavity; kotoule: cup) |
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Placental membrane development
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Prior to 20 weeks:
Syncytiotrophoblast Cytotrophoblast Villus connective tissue Fetal capillary endothelium After 20 weeks? |
Vasculosyncytial placental membrane remains:
Syncytiotrophoblast Villous connective tissue Fetal capillary endothelium |
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Amniotic fluid sources and function
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Early, derived from diffusion of fluid from the decidua through amnion
␣ After 12 weeks (14 weeks LNMP): Fetal urine *** Excreted lung fluid ␣ Volume peaks at about 36 weeks: ␣ 1000 -1200 cc ␣ Provides fluid-filled space for fetus to grow What if kidneys don't form? |
renal agenesis (no kidneys) --> fetus will not produce urine --> fetus will not have space to grow
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Amniotic fluid composition
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Water (99%)
Desquamated fetal skin cells Carbohydrates Fats Enzymes Hormones Salts (electrolytes, urea) What is the baby doing to the amniotic fluid? |
baby is constantly swallowing and urinating amniotic fluid (it's own pee! well, filtered pee really... it's mostly water lol)
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