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Fetal Circulation

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Fetal

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Fetal Circulation is the circulatory

system of a humanfetus, oftenencompassing the

entire fetoplacentalcirculation that alsoincludes the umbilicalcord and the blood

vessels within theplacenta that carryfetal blood.

The fetal circulationworks differently fromthat of born humans,because the lungs are

not in use: the fetusobtains oxygen andnutrients from themother through the

placenta and theumbilical cord.[1]

http://en.wikipedia.org/wiki/Circulatory_systemhttp://en.wikipedia.org/wiki/Circulatory_systemhttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Fetushttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Nutrienthttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Fetal_circulationhttp://en.wikipedia.org/wiki/Fetal_circulationhttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Nutrienthttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Fetushttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Circulatory_systemhttp://en.wikipedia.org/wiki/Circulatory_system

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Placenta is an organ that

connects thedeveloping fetus tothe uterine wall toallow nutrient uptake,

waste elimination, andgas exchange via themother's bloodsupply.

averages 22 cm(9 inch) inlength and 22.5 cm(0.81 inch) in

thickness

weighs approximately500 grams (1 lb)

has a dark reddish-blue

or maroon color. It connects to the fetus

by an umbilical cord

develops from same

sperm and egg cellsthat form the fetus, andfunctions as afetomaternal organ with

two components:a. fetal part (Chorion

frondosum)

b. maternal part

(Decidua basali

http://en.wikipedia.org/wiki/Organ_%28anatomy%29http://en.wikipedia.org/wiki/Fetushttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Chorion_frondosumhttp://en.wikipedia.org/wiki/Chorion_frondosumhttp://en.wikipedia.org/wiki/Decidua_basalishttp://en.wikipedia.org/wiki/Decidua_basalishttp://en.wikipedia.org/wiki/Decidua_basalishttp://en.wikipedia.org/wiki/Decidua_basalishttp://en.wikipedia.org/wiki/Chorion_frondosumhttp://en.wikipedia.org/wiki/Chorion_frondosumhttp://en.wikipedia.org/wiki/Chorion_frondosumhttp://en.wikipedia.org/wiki/Umbilical_cordhttp://en.wikipedia.org/wiki/Fetushttp://en.wikipedia.org/wiki/Organ_%28anatomy%29

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Placenta Function Nutrition and immunity

- allows the transfer of nutrients and oxygen fromthe mother to the fetus and the transfer of waste

products and carbon dioxide back from the fetus to themother.

- IgG antibodies pass through the human placenta,providing

protection to the fetus in uterus.

Secretes hormones that are important duringpregnancy.

a. Human Chorionic Gonadotropin (hCG).

- can be found in maternal blood and urine during

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Human ChorionicGonadotropin (hCG).-- the hormone

analyzed bypregnancy test; afalse-negative resultfrom a pregnancy test

may be obtainedbefore or after thisperiod.

- Women's blood

serum (-) for hCG by1-2 weeks after birth,is proof that allplacental tissue is

delivered.

hCG is only present

during pregnancybecause it is secreted

by the placenta, whichis present only[8]during pregnancy.

hCG ensures that the

corpus luteumcontinues to secreteprogesterone andestrogen.

Progesteronesecretion decreases,the endometrial liningslough off andpregnancy will be lost.

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Progesteroneprevents pretermlabor by reducingmyometrial

contraction. Levels ofprogesterone are highduring pregnancy.

Estrogen is referredto as the "hormone ofwomen" because itstimulates the

development ofsecondary female sexcharacteristics.

- contributes to thewoman's mammary

gland development inpreparation forlactation andstimulates uterine

growth toaccommodate

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Human PlacentalLactogen (hPL[Human ChorionicSomatomammotropin]) - This hormone islactogenic and growth-promoting properties.

- promotes mammarygland growth inpreparation for lactationin the mother.

- It regulates maternalglucose, protein, fatlevels so that this isalways available to the

fetus.

The placenta alsoprovides a reservoir ofblood for the fetus,delivering blood to it incase of hypotensionand vice versa

Fetal surfacesmooth & glistening sholtz

Maternal surface red

& freshlike duncan Large particles such

as bacteria cannotpass through thebarrier

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Placental expulsionbegins as aphysiological

separation from thewall of the uterus.

The period from justafter the fetus isexpelled until just afterthe placenta isexpelled is called thethird stage of labor.

The placenta isexpelled within 1530minutes of the baby

being born.

Placental expulsioncan be managed bygiving oxytocin via

intramuscular injectionfollowed by cordtraction to assist indelivering the

placenta.

Alternatively, it can bemanaged by allowingthe placenta to be

expelled withoutmedical assistance.

http://en.wikipedia.org/wiki/Placental_expulsionhttp://en.wikipedia.org/wiki/Oxytocinhttp://en.wikipedia.org/wiki/Oxytocinhttp://en.wikipedia.org/wiki/Placental_expulsion

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The umbilical cord also called the birth cord or

funiculus umbilicalis is theconnecting cord from the developingfetus to the placenta.

comes from the same zygote as the

fetus and contains two arteries (theumbilical arteries) and one vein (theumbilical vein), buried withinWharton's jelly.

The umbilical vein supplies the fetus:oxygenated, nutrient-rich blood fromthe placenta.

the umbilical arteries return the

deoxygenated, nutrient-depletedblood.

http://en.wikipedia.org/wiki/Fetushttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Zygotehttp://en.wikipedia.org/wiki/Arterieshttp://en.wikipedia.org/wiki/Umbilical_arterieshttp://en.wikipedia.org/wiki/Veinhttp://en.wikipedia.org/wiki/Umbilical_veinhttp://en.wikipedia.org/wiki/Wharton%27s_jellyhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Nutrienthttp://en.wikipedia.org/wiki/Bloodhttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Bloodhttp://en.wikipedia.org/wiki/Nutrienthttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Wharton%27s_jellyhttp://en.wikipedia.org/wiki/Umbilical_veinhttp://en.wikipedia.org/wiki/Veinhttp://en.wikipedia.org/wiki/Umbilical_arterieshttp://en.wikipedia.org/wiki/Arterieshttp://en.wikipedia.org/wiki/Zygotehttp://en.wikipedia.org/wiki/Placentahttp://en.wikipedia.org/wiki/Fetus

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joins the placenta,which transfersmaterials to and from

the mother's bloodwithout allowing directmixing.

is about 50centimeters (20 in)long and about 2centimeters (0.75 in)in diameter.

Wharton's jelly, agelatinous substancemade contains one

vein, which carriesoxygenated, nutrient-rich blood to thefoetus, and two

arteries that carrydeoxygenated,nutrient-depletedblood away.

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Associated Problems:

too short

- mechanical abruptio

- uterine inversion Associated Problems:

too long

cord coil

cord compression cord prolapsed

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Amniotic sac is the sac in which the

fetus develops inamniotes.

a tough but thintransparent pair ofmembranes, whichhold a developingembryo until birth.

The inner membrane,the amnion, containsthe amniotic fluid andthe fetus.

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The outer membrane,the Chorion, containsthe amnion and is partof the placenta.

It encloses theamniotic cavity and

the embryo. The amniotic cavity

contains the amnioticfluid.

On the outer side, theamniotic sac isconnected to the yolksac, to the allantois

and, through the

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Amniotic Fluid Also known as liquor

amnii is thenourishing andprotecting liquid

contained by theamniotic sac of apregnant woman.

The amniotic sac

grows and begins tofill with water,proteins,carbohydrates, lipids

and phospholipids,

http://en.wikipedia.org/wiki/Amniotic_sachttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Lipidhttp://en.wikipedia.org/wiki/Phospholipidhttp://en.wikipedia.org/wiki/Electrolytehttp://en.wikipedia.org/wiki/Ureahttp://en.wikipedia.org/wiki/Phospholipidhttp://en.wikipedia.org/wiki/Lipidhttp://en.wikipedia.org/wiki/Carbohydratehttp://en.wikipedia.org/wiki/Proteinhttp://en.wikipedia.org/wiki/Amniotic_sac

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Purposes Protects fetus against

blows or pressure onmothers abdomen

Protects the fetus

against the suddenchanges in temp.since liquid changestemp. more slowly

than air

Protects the fetusfrom infection

Provides freemovement for the

Amniocentesisremoval of amnioticfluid to diagnosedchromosomal

abnormalities Meconium stained

amniotic fluid in nonbreech presentation is

a sign of fetal distress

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During weeks 811,the fetus begins toswallow and urinate,

which is why theamniotic fluid containsfetal urine.

The volume ofamniotic fluidincreases as the fetusgrows approximately800 ml.

The amount of fluiddeclines when thebaby is born.

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The fore waters arereleased when theamnion ruptures. This is

commonly known as thetime when a woman's"water breaks (BOW).

When this occurs during

labour at term, it isknown as "spontaneousrupture of membranes"(SROM).

If the rupture precedeslabour at term, however,it is referred to as"premature rupture ofmembranes" (PROM).

The majority of thehind waters remaininside the womb until

the baby is born.

Artificial rupture ofmembrane (ARM), amanual rupture of theamniotic sac, can alsobe performed torelease the fluid if theamnion has not

spontaneouslyruptured.

http://en.wikipedia.org/wiki/Rupture_of_membraneshttp://en.wikipedia.org/wiki/Childbirthhttp://en.wikipedia.org/wiki/Gestationhttp://en.wikipedia.org/wiki/Premature_rupture_of_membraneshttp://en.wikipedia.org/wiki/Premature_rupture_of_membraneshttp://en.wikipedia.org/wiki/Premature_rupture_of_membraneshttp://en.wikipedia.org/wiki/Premature_rupture_of_membraneshttp://en.wikipedia.org/wiki/Gestationhttp://en.wikipedia.org/wiki/Childbirthhttp://en.wikipedia.org/wiki/Rupture_of_membranes

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Oligoscantyamount of

Amniotic fluidless than 500ccwhich may

result to fetaldistress

because no

enough fluid toequalize the

pressure

Polyhydramnios excessive

amount ofexcessive

Amniotic fluid> 1500-2000cc w/c

may result topreterm labor

or uterine

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Foramen Ovale

also called ostiumsecundum of Born orfalx septi

allows blood to enter

the left atrium from theright atrium.

one of two fetal cardiacshunts

closes at birth and lungsbecomes functional

It later forms the fossaovalis - an embryonic

remnant of the foramen

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Ductus Venosus

shunts approximatelyhalf of the blood flow ofthe umbilical veindirectly to the inferiorvena cava.

allows oxygenatedblood from the placentato bypass the liver

closes during the firstweek of life in full-termneonates; may takemuch longer to close in

pre-term neonates.

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After it closes, the

remnant is known asligamentum venosum.

If the ductus venosusfails to occlude afterbirth, the individual issaid to have an

intrahepaticportosystemic shunt(PSS).

Fetal circulation. The ductus venosus (red)connects the umbilical vein to the inferiorvena cava

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Ductus Arteriosus is a temporary fetal

blood vessel that

connects the aortaand the pulmonaryartery before birth.

the ductus arteriosusacts as a "short cut"

that allows blood tobypass the deflatedlungs and go straight

out to the body.

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After birth, when thelungs are needed to addoxygen to the blood, the

ductus arteriosusnormally closes.

Closure of the ductusarteriosus usually

occurs at birth as levelsof certain chemicals,called prostagladins,change, and the lungsfill with air.

If the ductus arteriosuscloses correctly, theblood pumped from theheart goes to the lungs,

back into the heart, and

The blood returningfrom the lungs andmoving out of the

aorta carries oxygento the cells of thebody.

In some infants, theductus arteriosusremains open (orpatent), and theresulting heart defectis known as patentductus arteriosus.

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The Flow Oxygenated blood

enters the umbilicalvein from theplacenta

oxygenated blood

bypass the liver viaductus venosus andcombines withdeoxygenated bloodin the inferior &superior vena cava

Enters the rightatrium

Enters the foramen

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Some blood enters theright ventricle but most

Enters pulmonaryartery with some bloodgoing to the lungs tosupply oxygen and

nourishment Flows to ductus

arteriosus

Enters descending

aorta ( blood going tothe lower extremities)

Goes back to theplacenta via umbilical

arteries

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The core conceptbehind fetal circulationis that fetalhemoglobin has a

higher affinity foroxygen than doesadult hemoglobin,which allows a

diffusion of oxygenfrom the mother'scirculatory system tothe fetus.

The branch of theumbilical vein thatsupplies the right lobeof the liver first joins

with the portal vein

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Summary

Structure Location Function

Placenta Attached to the uterus Gas exchange during fetal life

UmbilicalArteries

2 arteries in the cord Carry unoxygenated bloodfrom the fetus

Umbilical Vein 1 vein in the cord Carry oxygenated blood fromthe fetus

Foramen Ovale Opening in the interatrial septum(bet. the R & L atrium)

To shunt blood from the Ratrium to the L atrium so thatblood can be supplied tobrain, heart & kidney

Ductus Venosus Accessory vein connectingumbilical vein into fetal liver &inferior vena cava

To supply blood to the liver

DuctusArteriosus

Connection bet. fetal lungs & theaorta

Shunting of the larger portionof the blood away from thelungs & directly to the aorta