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Flashcards in Embryo/Repro Deck (227)
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1

What is seen with a mutation in the Sonic Hedgehog gene?

Holoprosencephaly

2

What is the function of the Wnt-7 gene?

Ventral-dorsal axis organization

3

What is the function of the FGF gene?

Found at apical ectodermal ridge (tip of limb). Stimulates mitosis of underlying mesoderm --> lengthening of limbs

4

What is the seen with mutation of the Homeobox genes?

Hox genes orient the embryo in the cranial-caudal direction. Mutations cause limbs in the wrong places.

5

When is a fetus most susceptible to teratogens?

Weeks 3-8

This is the embryonic period & is when most organs are formed.

6

When does gastrulation occur?

3 layers = Week 3 (trilaminar)

7

When during embryogenesis are the limbs formed?

4 limbs = Week 4

8

When can the sex of a baby be determined by US?

Week 10

9

When does the neural tube form during embryogenesis?

Weeks 3-4

10

What structures are formed from the neural crest?

PNS neurons
Schwann cells
Melanocytes
Parafollicular thyroid cells
Pia & arachnoid
Bones of the skull
Aorticopulmonary septum

11

What are the mesodermal defects?

CV LATER:

Cardiac defects
Vertebral defects
Limb defects
Anal atresia
Tracheo-Esophageal fistula
Renal defects

12

What structures are formed from the endoderm?

Lungs
Gut tube epithelium
Liver
Gallbladder
Pancreas
Thymus
Thyroid follicular cells
Parathyroid

13

What is the difference between agenesis & aplasia?

Agenesis = absent primordial tissue

Aplasia = Primordial tissue was present but organ is absent

14

What is the difference between Deformation & Malformation?

Malformation = intrinsic & occurred during embryogenesis

Deformation = Extrinsic & occurred after embryogenesis

15

What is the embryologic effect of ACE inhibitors?

Renal damage

16

What is the embryologic effect of alkylating agents?

Absence of digits & other anomalies

17

What is the embryologic effect of aminoglycosides?

CNVIII toxicity

Just like how they are ototoxic in adults

18

What is the embryologic effect of Lithium?

Ebstein's anomaly

Ebstein's = Atrialized RV = most of the right heart is atrium

19

What is the embryologic effect of phenytoin?

Fetal hydantoin syndrome:

Microcephaly
Dysmorphic craniofacial features
Hypoplastic distal phalanges & nails
Mental retardation
Cardiac defects
Intrauterine growth restriction

20

What is the embryologic effect of Tetracyclines?

Discolored teeth

21

What is the embryologic effect of thalidomide?

"Flipper" limb defects

ThaLIMBdomide

22

What is the embryologic effect of Valproic acid?

Inhibits maternal folate absorption --> neural tube defects

23

What is the embryologic effect of warfarin?

Bone deformities
Fetal hemorrhage
Ocular abnormalities

Use heparin during pregnancy

24

What is seen with cocaine use during pregnancy?

Abruptio placentae
Abnormal fetal development
Fetal addiction

25

What is seen with smoking during pregnancy?

Premature delivery
IUGR
ADHD

26

What can be seen in infants born to diabetic mothers?

Caudal regression syndrome (aka sacral agenesis; ranges from anal atresia to full blown sirenomelia)
Congenital heart defects
Neural tube defects
NRDS

27

When must separation occur to cause the various types of monozygotic twins?

dichorionic, diamniotic
4-8 days (morula) --> Monochorionic diamniotic
8-12 days (blastocyst) --> Mono-mono
> 13 days --> mono-mono & conjoined

28

What are the chorionic villi composed of?
Which cell type secretes hCG?

Cytotrophoblasts (inner layer)
Sincytiotrophoblasts (outer layer) - secrete hCG

29

What is the urachus?
What pathology is seen with it?

Allantois --> Urachus --> Median umbilical fold
Urachus is a duct between the bladder & yolk sack

1) Patent urachus --> Urine discharge from umbilicus
2) Vesiurachal diverticulum --> outpouching of bladder
3) Adenocarcinoma of the bladder

30

What is the Vitelline duct?
What pathology is seen with it?

It connects the yolk sac to the midgut lumen

1) Meckel's diverticulum
2) Vitelline fistula --> meconium discharge from umbilicus