Embryology

Question 1

natural screening of embryos

Answer 1

spontaneous abortion; likely in fetuses with cleft lip/palate, & neural tube defects

Question 2

implantation of embryo outside uterus

Answer 2

ectopic pregnancy

Question 3

where do most ectopic pregnancies implant?

Answer 3

ampulla (can cause abdominal pregnancy) & isthmus (early rupture from bursting of uterine/ovarian anastomoses)

Question 4

mucosal adhesions & pelvic inflammatory disease cause?

Answer 4

tubal pregnancies—> interferes with the transport of zygote to uterus; abdominal pain

Question 5

when zygotes can develop before rupture of ectopic pregnancy

Answer 5

intramural tubal pregnancy (uterine part of tube)

Question 6

which ectopic pregnancy can go full term?

Answer 6

abdominal pregnancy —-> intraperitoneal bleeding/risk of maternal death

Question 7

implantation of blastocyst in inferior segment of uterus & placenta blocks cervical opening

Answer 7

placenta previa; c-section required for complete blockage of canal

Question 8

high doses of estrogen & progesterone that inhibits implantation of embryo

Answer 8

morning after pill

Question 9

interferes with implantation by causing inflammatory reaction in the uterus

Answer 9

intrauterine device

Question 10

what hormone is released by a cleaving zygote?

Answer 10

early pregnancy factor (HCG)

Question 11

what produces human chorionic gonadotrophin (HCG)?

Answer 11

syncytiotrophoblast

Question 12

leakage of blood into uterine cavity from disrupted lacunar networks in blastocyst

Answer 12

implantation bleeding (can be a false negative for pregnancy)

Question 13

tumor that arises from remnants of primitive streak & contains tissues from 3 germ layers

Answer 13

sacrococcygeal teratomas; common in newborns (esp. females), benign

Question 14

tumor that arises from remnants of the notochord (1/3 from cranium to nasopharynx)

Answer 14

chordoma; if malignant, it grows into bone

Question 15

remnants of extraembryonic portion of allantois between fetal umbilical vessels

Answer 15

allantoic cysts —>symptomatic in childhood/adulthood when inflammed

Question 16

congenital herniation of viscera into proximal umbilical cord (associated with allantoic cysts)

Answer 16

omphalocele

Question 17

disturbance in the neuroectoderm & failure of neural folds to fuse causes?

Answer 17

neural tube defects

Question 18

partial or complete absence of brain

Answer 18

meroenchephaly/anencephaly

Question 19

cystic swellings formed by degenerative villi after death of embryo; high HCG

Answer 19

hydatidiform moles

Question 20

malignant moles that develop after spontaneous abortions or normal delivery; hematogenously metastastize

Answer 20

choriocarcinomas

Question 21

fertilization of empty oocyte by monospermic or dispermic moles

Answer 21

complete hydatidiform moles

Question 22

fertilization of oocyte by two sperms

Answer 22

partial hydatidiform moles

Question 23

hemolytic disease of newborn causing anemia, jaundice, hemolysis

Answer 23

fetal erythroblastosis; when fetus is Rh+ but mother is Rh-

Question 24

what’s given to mother to prevent fetal erythroblastosis?

Answer 24

Rh immunoglobulin

Question 25

abnormal proliferation of trophoblast

Answer 25

gestational trophioblastic disease (gestational choriocarcinomas)

Question 26

how do you treat gestational choriocarcinomas?

Answer 26

chemotherapy

Question 27

abnormal adherence of chorionic villi to myometrium

Answer 27

placenta accreta (3rd trimester bleeding)

Question 28

when chorionic villi penetrate entire myometrium into perimetrium

Answer 28

placenta percreta (3rd trimester bleeding)

Question 29

absence of umbilical artery

Answer 29

agenesis or degeneration of vessel in early development associated with 15-20% cardiovascular defect

Question 30

low volumes of amniotic fluid ---> rupture of amniochorionic membrane, placental insufficiency, reneal agenesis (no fetal urine)

Answer 30

oligohydraminos ---> fetal abnormalities & early rupturing of fetal membrane

Question 31

high volumes of amniotic fluid from fetus not swallowing enough fluid ---> esophageal atresia

Answer 31

polyhydraminos ---> an/meroencephaly

Question 32

rupture of amnion, & encircling by amniotic bands ---> digital constriction, major scalp, craniofacial, & visceral defects

Answer 32

amniotic band syndrome

Question 33

anastomoses between blood vessels of fused placentas of DZ twins

Answer 33

erythrocyte mosaicism

Question 34

shunt of twin blood through anastomoses into venous circulation of other twin; donor twin is anemic & recipient twin is polycythemic

Answer 34

twin transfusion syndrome (treat with lazer ablation)

Question 35

50% mortality rate because umbilical cords tangle

Answer 35

monochorionic-monamniotic twin placenta

Question 36

vascular abormalities, somatic mutations, chromosome abherrations, X chromosome inactivation

Answer 36

discordant MZ twins

Question 37

embryonic disks don't divide correctly

Answer 37

conjoined twins

Question 38

fertilization of two or more oocytes at different times

Answer 38

superfecundation