Placenta Lecture Powerpoint

Question 1

Cotyledons

Answer 1

Invaginations and folds that attach the placenta to the maternal wall, houses villi and membrane where exchange from spiral arteries of the uterus to the umbilical vein occurs, can be left behind in the uterus upon delivery

Question 2

Fetal maternal communication of circulatoin

Answer 2

There is no commingling of maternal and fetal blood in a healthy pregnancy, always separated in theory

Question 3

Pre-implantation genetic screening

Answer 3

Culturing of a blastocyst in a petri dish incubated followed by PCR to determine the genetic karyotyping (if its aneupleudy then won’t successfully thrive but if euploidy then implantable) where implanting has led to increased success of in vitro fertilization

Question 4

Zona pellucida

Answer 4

Wall that is penetrated by sperm enzymatically, remains intact and disappears just before implantation

Question 5

Fertilization takes place in the….

Implantation occurs in the…

Answer 5

….fallopian tube

….upper posterior wall of the uterus

Question 6

A pregnancy is undetectable until

Answer 6

8-10 days post conception (when it implants in the uterus and begins secreting hCG, undetectable before)

Question 7

Chorionic villi

Answer 7

Tufts of capillaries coming from the trophoblast developing on day 12 from fertilization, fetal blood vessels are functional with circulation established on day 19-21

Question 8

Spiral arteries of the uterus conversion (Vascular invasion of decidual cells) mech of action

Answer 8

• Trophoblasts invade maternal capillaries and destroy arterioles and spinal arteries vessels walls
• uterine tissue replaced with placental tissue, maternal smooth muscle replaced by SMOOTH MUSCLE LACKING cytotrophoblastic cells
• maternal veins not evolved
• Not autoregulated flow and spiral arteries converted to lacunae (lakes of blood) by becoming very dilated and causing maternal blood to enter in fountain like spurts engorging the area right outside the umbilical artery and vein capillaries, this flow is continuous until uterine contraction pressure limits it (no autoregulation)

Question 9

No matter what the mother’s blood sugar is, the baby’s is…

Answer 9

…higher

Question 10

Placental sequestration

Answer 10

The placenta sequesters zinc, copper, lead, and cadmium and other heavy metals, if in a poor developmental environment the baby can be born with toxic levels

Question 11

Do drugs and metabolites cross the placenta?

Answer 11

Yes, by diffusion (almost 10% of neonates are born addicted to substances)

Question 12

hCG is found in excessively high levels in these 3 conditions, and lower in these 2

Answer 12

• multiple pregnancies
• fetuses with anti-D rH disease
• down syndrome
• ectopic pregnancy
• impending abortion

Question 13

Amniotic fluid

Answer 13

Bound by the amnion, fluid that bathes the fetus detectable by 1st trimester as it diffuses into the amnion, 85% fetal urine, swallowed and absorbed into the fetal blood stream, diffuses across placental membrane back into the maternal space, excreted by kidneys and lungs of mother

Question 14

Umbilical vein

Answer 14

Carries o2 RICH blood from placenta to fetus that then bipasses the liver and into the right atria via the ductus venosus

Question 15

There are __ umbilical arteries (oxygen poor blood) and __ umbilical veins

Answer 15

2, 1

Question 16

Ligamentum teres

Answer 16

Remnant of the umbilical vein, free edge of the falciform ligament of the liver

Question 17

Placenta previa
Accreta
Increta
Percreta

Answer 17

• Occurs when the placenta implants over the cervical opening
• placenta implants in the decidua basalis
• placenta implants into the myometrium
• placenta implants into the serosal surface of the uterus or into bladder wall

Question 18

Mechanism of shifting from utero to newborn breath

Answer 18

• aeration of lungs causes them to inflate
• sees a dramatic fall in pulmonary vascular resistance and marked increase pulmonary blood flow causing pressure on right side of heart to decrease
• systolic systemic BP is about 75-80 mmHg, and pulmonary drops from 1/2 that to about 1/3rd, the foramen ovale and ligamentum arteriosum close by 1 year and 24 hours of this, respectively

Question 19

Risk factors for abnormal placental implantation (6)

Answer 19

• previa
• older mothers
• higher parity
• prior cesareans
• uterine scarring from ablation
• leiomyomas

Question 20

Complications of abnormal placental implantation (4)

Answer 20

• post partum hemorrahge***
• damage to bladder and bowels
• transfusion reactions
• ARDS

Question 21

The amnion

Answer 21

Innermost fetal membrane contiguous with amniotic fluid, avascular but metabolically active, provides tensile strength of fetal membranes

Question 22

Less than __mL at term is oligohydramnios, greater than __L is polyhydramnios, avg is ___mL

Answer 22

100ml, 2L, 1000mL

Question 23

Umbillical cord

Answer 23

Originated from the yolk sac, average length of 55cm, normal range 30-100cm, houses 2 arteries and 1 vein

Question 24

Amniotic bands syndrome

Answer 24

Rare malformation of the amnion and chorion that causes constricting of the tissue instead of a clear sac and can potentially strangulate extremities

Question 25

“I think I might be pregnant, my last period was 3 weeks ago, would the pregnancy test be positive?”

Answer 25

No it would be negative

Question 26

Thyroid hormone values in pregnancy, what is the active form of thyroid hormone?

Answer 26

• Free T3 and T4 decreased

- T3

Question 27

Bacteruria levels in nonpregnant vs pregnant indicating infection

Answer 27

Nonpreg >100,000 colonies/mL

Preg >10,000 colonies/mL

Question 28

Placental transfer methods (3)

Answer 28

• diffusion primarily (O2)
• facilitated transport (fetus spends energy to take up sugar and such)
• Maternal blood has higher affinity for CO2 than fetal blood drawing it out

Question 29

hCG alpha and beta subunits

Answer 29

alpha is identical to TSH FSH and LH

Beta is unique

Question 30

Ductus venosus

Answer 30

Fetal shunt from the umbilical vein bipassing the liver directly to the inferior vena cava

Question 31

Foramen ovale

Answer 31

Right atrial opening into the left atrium to bypass pulmonary circulation

Question 32

Ductus arteriosus

Answer 32

Opning to descending aorta from pulmonary arteries to bypass pulmonary circulation and return blood to the placenta from the umbilical arteries (division of anterior iliac in systemic circulation)

Question 33

Ductus venosus

Answer 33

Branch off the umbilical vein that bipasses the liver bringing blood direclty to the inferior vena cava, becoming the ligamentum venosum after birth

Question 34

Chorioamnion

Answer 34

Outer layer up against uterine uterine wall as placenta grows, not as strong as amnion, can be site of infection of meconium stanining