Embryology

Question 1

Holoprosencephaly can result from deficiency of which gene?

Answer 1

Sonic hedgehog

Question 2

Give the basic role in embryogenesis of each of the following genes: sonic hedgehog, Wnt-7, FGF, homeobox

Answer 2

SHH - antero-posterior patterning, Wnt-7 - dorsal-ventral patterning, FGF - limbs, Homeobox - segmentation

Question 3

Defect of which gene can lead to synpolydactyly (fusion of supranumery digits)

Answer 3

HOXD13

Question 4

What is the anterior pituitary an embryological derivative of?

Answer 4

Rathkes pouch, which is a derivative of surface ectoderm

Question 5

What structures does the neural crest give rise to (12)

Answer 5

ANS, DRG, CNs, Celiac ganglion, Melanocytes, Adrenal medulla, Parafollicular cells of thyroid, Schwann cells, Pia and arachnoid, bones of skull, odontoblasts, aorticopulmonary septum

Question 6

What is the embryologic derivation of melanocytes, the adrenal medulla, and parafollicular cells of the thyroid respectively?

Answer 6

All are from neural crest

Question 7

VACTERL

Answer 7

Mesodermal defects. Vertebral defects, Anal atresia, Cardiac defects, TE fisula, Renal defects, Limb defects (bone and muscle)

Question 8

Teratogenic effect of ACE inhibitors

Answer 8

Renal damage

Question 9

Teratogenic effect of alkylating agents

Answer 9

Absence of digits, multiple anomalies

Question 10

Teratogenic effect of aminoglycosides

Answer 10

CN 8 toxicity

Question 11

Teratogenic effect of carbamazepine

Answer 11

Neural tube defects, craniofacial defects, fingernail hypoplasia, developmental delay, IUGR

Question 12

Teratogenic effect of lithium

Answer 12

Ebsteins anomaly (atrialized right ventricle)

Question 13

Teratogenic effect of phenytoin

Answer 13

Fetal hydrantoin syndrome - microcephaly, dysmorphic craniofacial features, hypoplastic nails and distal phalanges, cardiac defects, IUGR, MR

Question 14

Teratogenic effect of tetracyclines

Answer 14

discolored teeth

Question 15

Teratogenic effect of valproate

Answer 15

Inhibits maternal folate absorption - neural tube defects

Question 16

Teratogenic effect of warfarin

Answer 16

Bone deformities, fetal hemorrhage, abortion, ophthalmologic abnormalities

Question 17

What teratogen is associated with ADHD?

Answer 17

Smoking

Question 18

Effects of maternal diabetes on the fetus

Answer 18

Caudal regression syndrome (anal atresia to sirenomelia), congenital heart defects, neural tube defects

Question 19

Microcephaly, holoprosencephaly, facial abnormalities (cleft lip and palate), limb dislocation, heart and lung fistulas, MR

Answer 19

Fetal alcohol syndrome

Question 20

What is the embryonic predecessor to the ascending aorta and pulmonary trunk

Answer 20

Truncus arteriosus

Question 21

What is the embryonic predecessor to the RV and smooth parts of the LV and RV

Answer 21

Bulbus cordis

Question 22

What is the embryonic predecessor to the trabeculated LV and RV

Answer 22

Primitive ventricle

Question 23

What is the embryonic predecessor to the trabeculated LA and RA

Answer 23

Primitive atria

Question 24

What is the embryonic predecessor to the coronary sinus?

Answer 24

Left horn of the sinus venosus

Question 25

What is the embryonic predecessor to the smooth part of the RA?

Answer 25

Right horn of the SV

Question 26

What is the embryonic predecessor to the SVC?

Answer 26

Right common cardinal vein and right anterior cardinal vein

Question 27

What heart defect is found in 20 to 30 percent of healthy adults?

Answer 27

Patent foramen ovale

Question 28

Give the fetal precursors for each of the following: umbilical vein, umbilical arteries, allantois, and notochord

Answer 28

Umbilical vein - ligamentum teres hepatis, umbilical arteries - medial umbilical ligaments, allantois - urachus-median umbilical ligament, notochord - nucleus pulposus of IV discs

Question 29

From what embryonic structure does the aqueduct of sylvius arise?

Answer 29

Mesencephalon

Question 30

Two causes of increased aFP during pregnancy

Answer 30

Neural Tube Defect and anterior abdominal wall defect (omphalocele)

Question 31

In syringomyelia what is in large, what is it associated with, and where does this most often occur?

Answer 31

Central canal of the spinal cord, Chiari II, C8-T1

Question 32

3rd aortic arch derivatives

Answer 32

Common carotid and proximal part of the internal carotid

Question 33

6th aortic arch derivatives

Answer 33

Proximal part of pulmonary arteries and ductus arteriosus

Question 34

What are the branchial clefts, arches, and pouches derived from respectively?

Answer 34

Clefts - ectoderm, arches - mesoderm and neural crests, pouches - endoderm

Question 35

A thyroglossal duct cyst is midline while a branchial cleft cyst is lateral. What is another easy way to tell them apart?

Answer 35

Branchial cleft cyst will not move on swallowing, thyrglossal duct cyst will

Question 36

Fate of branchial clefts 1-4

Answer 36

1 - external auditory meatus, 2 through 4 are obliterated

Question 37

Treacher Collins syndrome

Answer 37

Failure of 1st arch neural crest cells to migrate. Mandibular hypoplasia, facial abnormalities

Question 38

Cartilage, muscles, and nerves of branchial arch 1

Answer 38

Mandible, Malleus, incus, spheno-Mandibular ligament. Muscles of Mastication, Myelohyoid, ant 2/3 of tongue muscles. V2 and V3

Question 39

Cartilage, muscles, and nerves of branchial arch 2

Answer 39

Stapes, Styloid Process, lesser horn of hyoid, Stylohyoid ligament. Muscles of facial expression, Stapedius, Stylohyoid, post belly of digastric. CN 7

Question 40

Cartilage, muscles, and nerves of branchial arch 3

Answer 40

Greater horn of hyoid. Stylopharyngeus. CN 9

Question 41

Cartilage, muscles, and nerves of branchial archs 4-6

Answer 41

Thyroid, cricoid, arytenoid, corniculate, cuneiform cartilages. Cricothyroid lev veli palatini (4), intrinsic muscles of larynx except cricothyroid (6). CN 10 superior laryngeal br (4) and recurrent laryngeal branch (6)

Question 42

What nerve is at risk during thyroidectomy and what muscle may this paralyze?

Answer 42

Superior laryngeal nerve. Cricothyroid muscle (both from branchial arch 4)

Question 43

What is congenital pharyngeo-cutaneous fistula and what structure is it a defect in the development of?

Answer 43

Fistula between tonsillar area and clef in lateral neck. Branchial arch 3

Question 44

What branchial arch forms the posterior third of the tongue?

Answer 44

Arches 3 and 4

Question 45

Derivatives of branchial pouch 1

Answer 45

Middle ear cavity, eustachian tube, mastoid air cells

Question 46

Derivatives of branchial pouch 2

Answer 46

Epithelial lining of palatine tonsil

Question 47

Derivatives of branchial pouch 3

Answer 47

Inferior parathyroids (dorsal wings), and thymus (ventral wings)

Question 48

Derivatives of branchial pouch 4

Answer 48

Superior parathyroids (dorsal wings)

Question 49

DiGeorge syndrome is aberrant development of what embryonic structures?

Answer 49

Branchial pouches 3 and 4

Question 50

Cleft lip results from failure of fusion of what structures?

Answer 50

Maxillary and medial nasal processes

Question 51

Cleft palate results from failure of fusion of what structures?

Answer 51

Lateral palatine process, nasal septum, and/or median palatine process

Question 52

Gastroschisis

Answer 52

Extrusion of abdominal contents through abdominal folds and not covered by peritoneum

Question 53

Omphalocele

Answer 53

Persistence of herniation of abdominal contents into umbilical cord, covered by peritoneum

Question 54

What obstructs the rise of a horseshoe kidney?

Answer 54

IMA

Question 55

A bicornuate uterus results from failure to fuse of what structures?

Answer 55

The paramesonephric ducts

Question 56

What cell produces anti-mullerian hormone?

Answer 56

Sertoli cell