Placenta,amnioitic fluid and umbilical cord Flashcards Preview

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Flashcards in Placenta,amnioitic fluid and umbilical cord Deck (37)
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1
Q

Placenta

A
  • Temporary organ
  • Forms when trophoblast forms the chorion(3 layers)
  • will develop extensions(villi)
  • Transfer of substances between maternal and fetal systems
  • forms from two parts , trophoblast and endometrial lining from mom
  • villi-to exchange nutrients and waste products
2
Q

Components of the placenta

A
  • Embryonic(chorion frondosum)
  • Maternal(decidua basalis)
    • decidua -endometrial lining of uterine cavity
3
Q

Decidua(maternal component)

A
  • Decidua basalis-portion of endometrium underlying the implantation site
  • Decidua capsularis-portion overlying the implanted embryo and separating ti from the uterine cavity
    • Covering and capsule over implantation site
    • eventually lost as the amnioitic cavity enalrges and occupies all the sapce in the uterine cavity
  • Decidua parietalis-the remainder of the endometrium
    • these two wil fuse together and they will lose their individuality
  • These are areas of the endometrium lining the uterine cavity, but not part of the placenta
  • As the baby gets larger the uterine cavity gets lost
  • Myometrium-muscle that helps contract and push the baby
4
Q

Fetal component of the placenta

A
  • Chorion fondosum(chorionic plate)
  • area where villi develop(villious chorion)
  • VIlli are the agetns of exchange between maternal & fetal systems
  • Fetal surface of placenta should have chorionic(fetal) blood vessels
  • Going to have to grow into them a set of capillaries because diffusion is not enough
  • Chorion villi help make capillaries
5
Q

Primary chorionic villi

A
  • Solid outgrowths of cytotrophoblast that protrude into the syncytiotrophoblast
  • Start out in primary chorioinic villi
    • A little bump of cytotrophoblast
6
Q

Function of chorionic villi

A
  • oxygen and nutrients in the maternal blood in the intervillous spaces diffuse through the walls ov the villi and enter hte fetal capillaries
  • Carbon dioxide and waste products diffuse from blood in the fetal capillaries through the walls of the villi the maternal blood in the intervillous spaces
  • Need lots of sruface area but thin walls
  • cytotrophblast helps keep the capillaries open because you need the nutrients and oxygen
    • Get them into the fetal system
    • Needs lots of surface area and thin walls when wanting to move tons of different waste products
7
Q

Secondary chorionic villi

A
  • Have a core of lose connective tissue,which grows into the primary villi about the third week of development
8
Q

Teritary chorionic villi

A
  • Contain embryonic blood vessels
  • These blood vessels connect up with vessels that develop in the chorion and connecting stalk and begin to circulate embryonic blood about the third week of development
  • Thin coating of cytotrophoblast and other trophoblast
  • now you have blood vessels
  • by the end of week three we have built this sytem and can move blood around in the developing embryo
  • also have heart now that can beat
  • we will become more elaborate as the weeks go on
9
Q

Placental barrier

A
  • 1.syncytiotrophoblast
    1. cytotrophoblast
    1. Extraembryonic mesenchyme
    1. Fetal endothelium(single layered wall of fetal capillaries)
10
Q

Placental membrane

A
  • Not a strict barrier
  • Variety of substances cross freely
  • Beneficial or harmful
  • Some substances do not cross
11
Q

Substances that cross the Placenta

A
  • Beneficial:O2, CO2 glucose free fatty acids, vitamins
  • Harmful: rubella,measels , herpes, cytomegalovirus, variclla,poliomyelitis
  • Cat D: some antibiotics, Valium, Librium , Xanax, Lithium
    • Have been shown to cause congential deffects
  • Cat X drugs:thalidomide , warfarin, isotretinoin , nicotine,alcohol, phenytoin
    • Thalidomide-disrupts the signaling ,and stops the growth of hte limbs from growing properly
    • FAS-worse tetraogens we deal with
  • Warfarin
    • Coumadin
    • Anticoagulant
  • Phenytoin
    • Antiepileptic
12
Q

Isotretinoin

A
  • Used to treat severe acne that is resistant to more conservative treatments
  • Because of its serious side effects, isotretinoin should be used only for severe resistant acne
  • Sotret, Claravis , Amnesteem
13
Q

Erythroblastosis fetalis(Rh factor)

A
  • Rh-negative mother with Rh-positive fetus will produce antibodies
  • First pregnancy unaffected
  • Antibodies in 2nd pregnancy with Rh-positive fetus
  • Destruction of fetal RBCs
  • Brain damage to fetus& severe edema(hydrops fetalis)
  • Some of the fetal cells will be left and will develop antibodies for it
  • subsequent pregnancis will be problematic and mom’s antibodies will attack the embryo becasue it think it’s a foreign figure
14
Q

Symptoms in newborn baby for Erythroblastosis fetalis

A
  • Anemia
  • Edema(swelling under the surface of the skin)
  • Enlarged liver or spleen
  • Hydrops(fluid throughout the body’s tissues,inclduing in the spaces containing the lungs, heart, and abdominal organs)
  • Newborn jaundice
15
Q

treatment for erythroblastosis fetalis

A
  • RhoGAM
  • Human immunoglogin wiht antibodies against the Rh factor
  • prevents maternal antibody response to Rh-positive cells for the fetus
  • third trimester or after devlivery ,give her a dose of RhoGAM and it will stop mom’s antibodies from attacking the baby
16
Q
A
17
Q

Chorionic Villus Sampling

A
  • test for familial genetic disorders,advanced maternal age(chromosomal abnormalities)
  • Chorionic villlus sampling can be done earlier in pregnancy(at 10 to 12 weeks) than amniocentesis(usually done at 15 to 20 weeks
  • You can find out the karotype to determin the genetic health of that child
  • Very dangerous proceudre and transabdominal procedure can poke the developing fetus on accident
18
Q

Umbilical(Placental) vessels

A
  • Wharton’s jelly is a placental cord(umbilical cord) gelatinous connective tissue
  • It is seen at parurition when it increases in volume to assist closure of placental blood vessels
  • Matrix cells from wharton’s jelly have recently been identified as a potential source of stem cells
  • This placental cord substance is named after thomas wharton(1614-1673) an english physician and anatomist who first described it
  • vein kinda of functions like an artery
  • Wharton’s jelly-gelantinous viscousconnective tissue
    • increases in volume irhgt before birth
    • helps squeeze down the lumen and helps the vessel collapse
    • a place where you can get stem cell, and don’t have to interact with embryo blast
19
Q

Why is htere one umbilical vein?

A
  • During development ,there are two umbilical veins that drain blood from the placenta to the heart
  • Right umbilical vein regresses and under normal circumstances is completely obliterated during the second month development
  • Left umbilical vein persists and delivers blood from the placenta to the developing fetus
20
Q

Persisten right umbilical vein

A
  • PRUV is an uncommon anomaly
  • Present in 2~1000 briths
  • Normally the right umbilical vein begins to obliterate in the 4th week of gestation and disappears by the 7th week
21
Q

Velamentous cord

A
  • Virtually unprotected for long periods of teim, and easier to get a knot into this
  • Easier for damage to occur at child birth
  • Doesn’t mean you can’t do a vagina lbrith just need to watch babie’s heart rate and oxygen

If the placent is unstable then go for C section

  • Fetal blood vessels travel abnormally
  • Pass through amniochorionic membrane before reaching the placenta
  • These vessels are more exposed to trauma during the birth process
22
Q

Placenta Previa

A
  • Implantation of the placenta over the cervical os(opening)
  • covers internal opening of cervix(os)
  • a low-lying placenta is near the cervical opening but not covering it
  • partial placenta previa covers part of hte cervical oepning
  • total placenta previa covers and blocks the cervical opening
23
Q

Placenta Accreta

A
  • Abnormal trophoblastic invasion into the muscular layer of the uterus(placenta increta) or through the uterine wall and into surrounding tissues(placenta percerta)
  • Placenta accreta-the placental roots grow too deeply into the muscular wall of the uterus
  • Placenta increta-the placenta invades through the muscle of the uterus
  • Placenta percreta-the placenta pushes through the uterine wall and invades into other organs, like the bladder
    • Run into the same problems with ectopic pregnancy and no mechanism to shut off blood supply
      • hope to reabsorb and do a C section
24
Q

Placenta as an Endocrine Organ

A
  • Synthesizes glycogen, cholesterol and fatty acids
  • Nutrients,oxygen some immunoglboulins
  • remove waste products
  • synthesis and release of hormones
  • Most synthesized in the syncytiotrophoblast
  • human chorionic gonadotropin(hCG)-stimulates production of progesterone by the ovary(corpus luteum)
  • Chorionic somatomammotropin
    • aka human placental lactogen(hPL)
    • induces lipolysis, elevating free fatty acids in mother
    • “growth hormone” of the fetus
25
Q

Progesterone

A
  • Steroid hormone that maintains the endometrial lining during pregnancy also suppresses contractility in uterine smooth muscle
26
Q

Estrogens

A
  • Steroid hormones, stimulate mammary gland development
27
Q

Placental calcification

A
  • Calcification is a sign of placental aging
  • The pattern of calcification(precipitation of calcium hydroxyapatite) is similar to that seen in other aging tissues
  • Probably a response to cell death and diminshed blood circulation in localized regions of the placenta
  • one significant risk ractor-smoking
28
Q

Lithopedion

A
  • Fetal death with an ectopic pregnancy(usually)
  • The fetus is too large to be reabsorbed by the body and calcifies
29
Q

Functions of Amniotic Fluid

A
  • Permits symmetrical external growth
  • Enables fetus to move freely
  • Acts as a barrier to infection
  • Permits normal fetal lung development
  • Prevents adherence of amnion to embryo/fetus
  • Helps maintain homeostais
  • lets baby grow symetrically
  • make sure it gets right temperature , electrolytes
  • helps the lung expans and pracitice breathing
30
Q

Ligohydramnios

A
  • Low volume of amniotic fluid
  • associated with renal agenesis & obstructive uropathy
  • complications-pulmonary hypoplasia & limb defects
  • too little amniotic fluid, if you dont’ have enough the major tissues are renal agenesis is bad(where kidney’s dont form)
  • If potter syndrome-the failures of the kidney to develop, if you dont have kidney’s can’t supplement the amnioitic fluid
  • Fetal compression and not enough fluids can’t move around
  • Pulmonary hypoplasia-not enough fluid in there for the fetus to pracitice breathing and the lungs to devlop normally (usually kills the kid)
31
Q

Potter syndrome

A
  • PUlmonary hypoplasia-for normla development amniotic fluid must be brought into lung by fetal breathing movements ,leading to distension of the developing lung
32
Q

Polyhydramnios

A
  • High volume of amniotic fluid
  • Associated with CNS anomalies & esophageal atresia
  • What babies do to decrease amniotic fluid and practice swallowing
  • Goes to the GI tract to get processess and helps keep it in normal range
    • baby is trying to swallow and odens’t get through
    • Baby can’t swallow
  • Get a huge overgrowth of epithilium and doesn’t reopen and baby has problems swallowing and can’t get through the esophagus
    • if it’s in the dueodenum can process some of it
    • Can fix this problem relatively easy, if somethign wrong with the brain a lot more serious
33
Q

Amniotic band syndrome

A
  • Tears in the amnion detach and surround fetus
  • or adhesions between the amnion and affected strcutrues
  • May cause ring constrictions or amputations of limbs or digits
  • Shouldn’t have tears in the membrane
    • Get pieces of the amniotic membrane that warp around the limb
    • when it deos that you get constrictions in developing limbs, can get amputations depending on constriction
34
Q

Vasculogenesis

A
  • Blood vessels arise from coalescence of hemangioblasts which arise from blood isalnds
  • major vessels form via this way
  • Early in development it starts off in the yolk sac
    • gets little clumps of mengioblast which develops into vessels
    • Once we have enough fetal development we transfer it to the embryo
35
Q

Angiogenesis

A
  • Vessel formation via branches arising from exisiting vessels
  • smaller ones from via angiogenesis
36
Q

Definitive hematopoietic stem

A
  • Formation of blood cells in the yolk sac is transitory
  • Definitive hematopoietic cells arise from mesoderm around the aorta
  • Aorta-gonad-mesonephros region(AGM)
  • These cells will colonize the liver
  • The are in the fetus that will take over the development of red white blood cells
  • Eventually it will move out of hte AGM and go into the liver
  • 7 months into development, bone marrow takes over and the major site of the development of blood cells
37
Q

Hematopoietic tissue in the fetus

A
  • Stem cels colonize the liver- major hemaopoietic organ of the fetus
  • Later stem cells from the liver colonize the spleen, thymus and ultimately the bone marrow