Embyrology Clinical Correlates

Question 1

Conjoined Twins

Answer 1

Partial Splitting of Node and Streak (Week 3/4)

Question 2

Sirenomelia

Answer 2

aka mermaid syndrome. Insufficiant mesoderm formation in caudal region. bladder and kidney development impaired. death usually occurs within 2 days

Question 3

Chordoma

Answer 3

Tumor in remnants of notochord. develop intercranially/scarally. usually evident in 40+ years of age

Question 4

Gastroschisis

Answer 4

adominal wall decfect (ectoderm). organs spill out into amniotic fluid and around fetus

Question 5

Defective trophoblast (minimal hCG)

Answer 5

If trophoblast defective, two things could result: Not enough hCG, which means corpus luteum will not support pregnancy.

Question 6

defective trophoblast (too much hCG)

Answer 6

with little to no embryonic tissue, a Hydatidiform mole occurs and secretes a large amount of hCG (benign or malignant tumor). end in spontaneous miscarriage or abortion

Question 7

Sacrococcygeal Teratoma

Answer 7

Week 3. most common tumor in new borns. remnants of primitive streak in sacrococcygeal area. could contain tissue of all 3 germ layers. large tumor.

Question 8

Abnormal Blastocysts

Answer 8

Do not produce any sign of pregnancy because trophoblast is defective and could not produce sufficient hCG necessary to maintain corpus luteum

Question 9

Hydatidiform Moles

Answer 9

• Trophoblast develops and forms placental membranes with little or no embryonic tissue present
• Contains “grape-like” vesicles
• These moles secrete high levels of hCG ad may produce benign or malignant tumors
• End as spontaneous abortion (miscarriage)

Question 10

In Vitro Fertilization

Answer 10

• Mature oocytes from stimulated ovaries are received transvaginally with sonographic guidance
• Sperm and ova are the combined in vitro to prompt fertilization
• if successful, viable embryos are transferred transcervically into the endometrial cavity using sonographic guidance

Question 11

IntraCytoplasmic Sperm Injection (ICSI)

Answer 11

• Applicable to male factor infertility
• Corona Radiata is enzymatically digested
• Single sperm is directly injected through zona pellucida and oocyte cell membrane

Question 12

Placenta Previa

Answer 12

• Abnormal implantation in the uterus
• The blastocyst may implant close to the internal os (opening) of the cervix
• In this case, the placenta may cover the internal os, resulting in painless vaginal bleeding in the latest stages of pregnancy

Question 13

Ectopic Pregnancy

Answer 13

• Abnormal implantation outside of the uterus
• 95% of ectopic pregnancies occur in the uterine tube (tubal pregnancy)
• signs and symptoms of pregnancy, with abdominal pain and tenderness
• may also implant in the abdominal cavity, often in the rectouterine pouch (Pouch of Douglas)