I want my baby back (Embryology!)

Question 1

Sonic hedgehog gene

Answer 1

Produced @ base of limbs in zone of polarizing activity Involved in patterning along anterior-posterior axis

Question 2

Wnt-7 gene

Answer 2

Produced @ apical ectodermal ridge (thickened ectoderm at distal end of each developing limb) Necessary for proper organizing along dorsal-ventral axis

Question 3

FGF gene

Answer 3

Produced at apical ectodermal ridge Stimulates mitosis of underlying mesoderm, providing for lengthening of limbs

Question 4

Homeobox (Hox) genes

Answer 4

Involved in segmental organization of embryo in craniocaudal directon Hox mutations –> appendages in wrong locations

Question 5

Embryonic period

Answer 5

Weeks 3-8; extremely susceptible to teratogens

Question 6

What is the most common type of monozygotic twin?

Answer 6

Monochorionic, Diamniotic Cleavage at 4-8 days, Morula phase

Question 7

Name the components of the placenta

Answer 7

Fetal components: Cytotrophoblast- inner layer of chorionic villi, makes cells Syntytiotrophoblast- outerlayer of chorionic villi, secretes hCG Maternal component: Decidua basalis (derived from endometrium)

Question 8

Urine vs stool discharge from umbilicus

Answer 8

Urine- patent urachus Stool- vitelline fistula

Question 9

Umbilical vessels

Answer 9

2 arteries- return deoxygenated blood from fetal internal iliac arteries to placenta 1 vein- supplied oxygenated blood from placenta to fetus; drains into IVC

Question 10

Truncus arteriosus

Answer 10

Gives rise to ascending aorta & pulmonary trunk *Pathology: transposition of great vessels (failure to spiral), tetralogy of Fallot (skewed AP septum development) or persistent TA (partial AP septum development

Question 11

Bulbus cordis

Answer 11

Gives rise to R ventricle & outflow tracts of L & R ventricle

Question 12

Primitive ventricle

Answer 12

Gives rise to trabeculated L & R ventricle

Question 13

Primitive atria

Answer 13

Gives rise to trabeculated L & R atria

Question 14

Left horn of sinus venosus

Answer 14

Gives rise to coronary sinus

Question 15

Right horn of sinus venosus

Answer 15

Gives rise to smooth part of R atrium

Question 16

Right common cardinal vein & right anterior cardinal vein

Answer 16

Gives rise to SVC

Question 17

Sites of fetal erythropoiesis

Answer 17

Yolk sac (3–8 weeks) Liver (6-20 weeks) Spleen (9-28 weeks) Bone marrow (28 weeks onward)

Question 18

3 shunts in fetal circulation

Answer 18

1. Ductus venousus Umbilical vein –> IVC therefore bypassing hepatic circulation 2. Foramen ovale Blood from IVC diverted out aorta 3. Ductus arteriosus Blood from SVC expelled into pulmonary artery & ductus arteriosus to reach lower body

Question 19

Drugs to open/close PDA

Answer 19

Indomethacin closes PDA Prostaglandins keep PDA Patent

Question 20

Derivatives of primary vesicles

Answer 20

Forebrain (prosencephalon) Midbrain (Mesencephalon) Hindbrain (Rhombencephalon)

Adult derivatives of cavities: Lateral ventricles, 3rd ventricle, aqueduct, upper part of 4th ventricle, -, lower part of 4th ventricle

Question 21

Aortic arch derivatives

Answer 21

1- Maxillary artery 2- Stapedial artery, hyoid artery 3- common carotid artery, proximal part of internal carotid artery 4- aortic arch on L, proximal R subclavian on R 6- proximal part of pulmonary arteries & ductus arteriosus

Question 22

Derivatives of branchial appartatus

Answer 22

Clefts- ectoderm Arches- mesoderm & neural crests Pouches- endoderm

Question 23

Branchial cleft derivatives (aka pharyngeal grooves)

Answer 23

1: External auditory meatus 2-4: temporary cervical sinuses *Persistent cervical sinus—> branchial cleft cyst

Question 24

Branchial arch derivates

Answer 24

1- CHEW 2- SMILE 3- SWALLOW STYLISHLY 4- SIMPLY SWALLOW 6- SPEAK

Question 25

Branchial pouch derivatives

Answer 25

1- middle ear cavity, eustachian tube, mastoid air cells 2- epithelial lining of palatine tonsils 3- inferior parathyroids (dorsal wings) & thymus (ventral wings) 4- superior parathyroids

Question 26

Foramen cecum

Answer 26

Remnant of thyroglossal duct

Question 27

Thyroglossal duct cyst vs branchial cleft cyst

Answer 27

Thyroglossal duct cyst- midline, moves w/ swallowing Branchial cleft cyst- persistent cervical sinus in lateral neck

Question 28

Cleft lip vs cleft palate

Answer 28

Cleft lip- failure of fusion of maxillary & medial nasal processes (formation of primary palate) Cleft palate- failure of fusion of lateral palatine processes, nasal septum, and/or median palatine process (formation of secondary palate)

Question 29

Derivatives of foregut, midgut, & hindgut

Answer 29

Foregut- pharynx to duodenum Midgut- duodenum to transverse colon Hindgut- distal transverse colon to rectum

Question 30

Most common type of TE fistula

Answer 30

Type C

Question 31

Pancreas origin

Answer 31

Foregut Ventral bud forms uncinate process Dorsal bud becomes everything else

Question 32

Spleen origin

Answer 32

Dorsal mesentery BUT supplied by celiac artery, an artery from the foregut

Question 33

Kidney embryology

Answer 33

Pronephros- week 4, then degenerates Mesonephros- interim kidney for 1st trimester; ultimately becomes ductus deferens & epididymis in males Metanephros- permanent

Question 34

Components of metanephros

Answer 34

Ureteric bud- derived from caudal end of mesonephros; gives rise to ureter, pelvises, calyces, & collecting ducts Metanephric mesenchyme- interacts w/ ureteric bud to form glomerulus, renal tubules to distal convoluted tubule

Question 35

Mesonephric duct

Answer 35

AKA wolffian duct Becomes male internal structures except prostate

Question 36

Paramesonephric duct

Answer 36

AKA mullerian duct Becomes female internal structures

Question 37

Bicornate uterus

Answer 37

Due to incomplete fusion of paramesonephric ducts