Step1-Embryology

Front 1

gene responsible for anterior posterior axis patterning of limbs?

Back 1

Sonic hedgehog gene

Front 2

gene responsible for dorsal-ventral axis patterning?

Back 2

Wnt-7 gene

Front 3

gene that stimulates mitosis of underlying mesoderm, providing for lengthening of limbs?

Back 3

FGF gene

Front 4

Segmental organization of embryo in craniocaudal direction?

Back 4

Homeobox gene

Front 5

at what time in fetal development does blastocyst implant and hCG secretion start?

Back 5

within week 1

Front 6

at what time in fetal development does bilaminar disk develop?

Back 6

week 2

Front 7

at what time in fetal development does gastrulation occur?

Back 7

week 3

Front 8

at what time in fetal development does primitive streak, notochord, and neural plate begin to form?

Back 8

week 3

Front 9

at what time in fetal development does neural tube close?

Back 9

week 4

Front 10

at what time in fetal development does organogenesis occur?

Back 10

weeks 3-8

Front 11

at what time in fetal development does embryonic period occur?

Back 11

weeks 3-8

Front 12

at what time in fetal development is the fetus most susceptible to teratogens?

Back 12

weeks 3-8

Front 13

at what time in fetal development does heart begin to beat?

Back 13

week 4

Front 14

at what time in fetal development do upper and lower limb buds begin to form?

Back 14

week 4

Front 15

at what time in fetal development does fetal movement begin?

Back 15

week 8

Front 16

at what time in fetal development is genitalia distinguishable male/female?

Back 16

week 10

Front 17

alar vs. basal plate?

Back 17

alar plate: dorsal, sensory
basal plate: ventral, motor

Front 18

role of notochord in neural development?

Back 18

induces overlying ectoderm to differentiate into neuroectoderm and form neural plate; becomes nucleus pulposus of intervertebral disk in adults

Front 19

source and fate of primitive streak?

Back 19

derived from invagination of epiblst; gives rise to intraembryonic mesoderm and part of endoderm

Front 20

rule of 2's for 2nd week?

Back 20

2 germ layers (epiblast, hypoblast)
2 cavities (amniotic cavity, yolk sac)
2 components to placenta (cytotrophoblast, syncytiotrophoblast)

Front 21

rule of 3's for 3rd week?

Back 21

3 germ layers (ectoderm, mesoderm, endoderm)

Front 22

rule of 4's for 4th week?

Back 22

4 heart chambers
4 limb buds grow

Front 23

craniopharyngioma?

Back 23

benigh Rathke's pouch tumor with cholesterol crystals, calcifications

Front 24

source of lens of eye, sensory organs of ear?

Back 24

surface ectoderm

Front 25

source of epithelial linings of oral cavity, olfactory epithelium?

Back 25

surface ectoderm

Front 26

source of epidermis?

Back 26

surface ectoderm

Front 27

source of salivary, sweat, and mammary glands?

Back 27

surface ectoderm

Front 28

source of retina cells?

Back 28

neuroectoderm

Front 29

source of dorsal root ganglia, cranial nerves?

Back 29

neural crest cells

Front 30

source of melanocytes and parafollicular cells of thyroid?

Back 30

neural crest cells

Front 31

source of bones of skull?

Back 31

neural crest cells

Front 32

source of pia and arachnoid?

Back 32

neural crest cells

Front 33

source of odontoblasts?

Back 33

neural crest cells

Front 34

source of chromaffin cells of adrenal medulla?

Back 34

neural crest cells

Front 35

source of lungs, liver, pancreas?

Back 35

endoderm

Front 36

which germ cell layer is source of thymus, parathyroid?

Back 36

endoderm

Front 37

source of thyroid follicular cells?

Back 37

endoderm

Front 38

source of peritoneum?

Back 38

mesoderm

Front 39

source of spleen?

Back 39

mesoderm

Front 40

source of cardiovascular structures, lymphatics, blood?

Back 40

mesoderm

Front 41

source of adrenal cortex?

Back 41

mesoderm

Front 42

source of eustachian tube?

Back 42

mesoderm

Front 43

source of testes/ovaries?

Back 43

mesoderm

Front 44

teratogenic effect of ACE inhibitors?

Back 44

renal damage

Front 45

teratogenic effect of alcohol?

Back 45

fetal alcohol syndrome; mental retardation

Front 46

teratogenic effect of alkylating agents?

Back 46

absence of digits, multiple other anomalies

Front 47

teratogenic effect of aminoglycosides?

Back 47

CN VIII toxicity

Front 48

teratogenic effect of cocaine?

Back 48

abnormal development
fetal addiction
placental abruption

Front 49

teratogenic effect of diethylstilbestrol?

Back 49

vaginal clear cell adenocarcinoma

Front 50

teratogenic effect of folate antagonists?

Back 50

neural tube defects

Front 51

teratogenic effect of iodide?

Back 51

congenital goiter or hypothyroidism

Front 52

teratogenic effect of lithium?

Back 52

ebstein's anomaly (atrialized right ventricle)

Front 53

teratogenic effect of maternal diabetes?

Back 53

caudal regression syndrome (anal atresia to sirenomelia)

Front 54

teratogenic effect of smoking (nicotine, CO)

Back 54

preterm labor, placental problems, IUGR, ADHD

Front 55

teratogenic effect of tetracyclines?

Back 55

discolored teeth

Front 56

teratogenic effect of thalidomide?

Back 56

limb defects ("flipper" limbs)

Front 57

teratogenic effect of valproate?

Back 57

inhibition of intestinal folate absorption

Front 58

teratogenic effect of excess vitamin A?

Back 58

spontaneous abortions, cleft palate, cardiac anomalies

Front 59

teratogenic effect of warfarin?

Back 59

bone deformities, fetal hemorrhage, abortion

Front 60

teratogenic effect of anticonvulsants?

Back 60

multiple abnormalities

Front 61

inner vs. outer layer of chorionic villi?

Back 61

inner layer: cytotrophoblast
outer layer: syncytiotrophoblast

Front 62

which cells from chorionic villi secrete hCG?

Back 62

syncytiotrophoblast

Front 63

structure of umbilical cord vessels?

Back 63

two arteries, one vein; derived from allantois

Front 64

urine discharge from umbilicus?

Back 64

patent urachus (duct between bladder and yolk sac)

Front 65

meconium discharge from umbilicus?

Back 65

failure of vitelline duct to close (omphalo-mesenteric duct)

Front 66

Meckel's diverticulum?

Back 66

partial closure of vitelline duct

Front 67

embryonic structure that gives rise to right ventricle and outflow tract?

Back 67

bulbus cordis

Front 68

embryonic structure that gives rise to ascending aorta and pulmonary trunk?

Back 68

truncus arteriosus

Front 69

embryonic structure that gives rise to trabeculated left and right atrium?

Back 69

primitive atria

Front 70

embryonic structure that gives rise to coronary sinus?

Back 70

left horn of sinus venosus

Front 71

embryonic structure that gives rise to smooth part of right atrium?

Back 71

right horn of sinus venosus

Front 72

embryonic structure that gives rise to SVC?

Back 72

right common cardinal vein and right anterior cardinal vein

Front 73

failure of what developmental process leads to transposition of great vessles?

Back 73

failure of truncal and bulbar ridges to spiral as they fuse to form aorticopulmonary septum

Front 74

embryological equivalent of fossa ovalis?

Back 74

foramen ovale (opening in septum secundum )

Front 75

when does fetal erythropoiesis occur in yolk sac?

Back 75

3-8 weeks

Front 76

when does fetal erythropoiesis occur in liver?

Back 76

6-30 weeks

Front 77

when does fetal erythropoiesis occur in spleen?

Back 77

9-28 weeks

Front 78

when does fetal erythropoiesis occur in bone marrow?

Back 78

after 28 weeks

Front 79

composition of fetal hemoglobin?

Back 79

alpha2-gamma2

Front 80

three important shunts in fetal circulation?

Back 80

1. ductus venosus bypasses hepatic circulation
2. foramen ovale bypasses pulmonary circulation
3. ductus arteriosus shunts deoxygenated blood from SVC to lower body instead of pulmonary circulation

Front 81

medication effects on patent ductus arteriosus?

Back 81

indomethacin helps close
prostaglandins keep open

Front 82

derivatives of prosencephalon?

Back 82

•telencephalon -> cerebral hemispheres
•diencephalon -> thalami, etc

Front 83

derivatives of mesencephalon?

Back 83

midbrain

Front 84

derivatives of rhombencephalon?

Back 84

•metencephalon -> pons and cerebellum
•myelencephalon -> medulla

Front 85

amniotic fluid finding in neural tube defects?

Back 85

increased alpha-fetoprotein

Front 86

where is most common location for syringomyelia?

Back 86

C8-T1

Front 87

derivative of 1st aortic arch?

Back 87

Maxillary artery

Front 88

derivative of 2nd aortic arch?

Back 88

stapedial artery and hyoid artery

Front 89

derivative of 3rd aortic arch?

Back 89

common carotid artery and proximal part of internal carotid

Front 90

derivative of 4th aortic arch?

Back 90

on left, aortic arch
on right, proximal part of right subclavian artery

Front 91

derivative of 6th aortic arch?

Back 91

proximal part of pulmonary arteries and (on left) ductus arteriosis

Front 92

derivative of 1st branchial cleft?

Back 92

external auditory meatus

Front 93

derivative of 2nd-4th branchial clefts?

Back 93

temporary cervical sinuses, obliterated by proliferation of 2nd arch mesenchyme

Front 94

branchial source of mandible and spheno-mandibular ligament?

Back 94

first branchial arch

Front 95

branchial source of malleus, incus?

Back 95

first branchial arch

Front 96

branchial source of muscles of mastication?

Back 96

first branchial arch

Front 97

branchial source of tensor veli palatini?

Back 97

first branchial arch

Front 98

branchial source of anterior 2/3 of tongue?

Back 98

first branchial arch

Front 99

branchial source of CN V2 and V3?

Back 99

first branchial arch

Front 100

branchial source of stapes?

Back 100

second branchial arch

Front 101

branchial source of styloid process?

Back 101

second branchial arch

Front 102

branchial source of lessor horn of hyoid?

Back 102

second branchial arch

Front 103

branchial source of stylohyoid ligament?

Back 103

second branchial arch

Front 104

branchial source of muscles of facial expression?

Back 104

second branchial arch

Front 105

branchial source of stapedius?

Back 105

second branchial arch

Front 106

branchial source of stylohyoid?

Back 106

second branchial arch

Front 107

branchial source of posterior belly of digastric?

Back 107

second branchial arch

Front 108

branchial source of anterior belly of digastric?

Back 108

first branchial arch

Front 109

branchial source of CN VII?

Back 109

second branchial arch

Front 110

branchial source of greater horn of hyoid?

Back 110

third branchial arch

Front 111

branchial source of stylopharyngeus?

Back 111

third branchial arch

Front 112

branchial source of CN IX?

Back 112

third branchial arch

Front 113

branchial source of thyroid?

Back 113

branchial arch 4-6

Front 114

branchial source of arytenoids?

Back 114

branchial arch 4-6

Front 115

branchial source of cricoid cartilage?

Back 115

branchial arch 4-6

Front 116

branchial source of levator veli palatini?

Back 116

fourth branchial arch

Front 117

branchial source of intrinsic muscles of larynx?

Back 117

sixth branchial arch (except for cricothyroid from 4th branchial arch)

Front 118

branchial source of posterior 1/3 of tongue?

Back 118

branchial arch 3 and 4

Front 119

branchial source of CN X?

Back 119

fourth branchial arch: superior laryngeal branch
sixth branchial arch: recurrent laryngeal branch

Front 120

branchial source of middle ear cavity and eustachian tube?

Back 120

first branchial pouch

Front 121

branchial source of mastoid air cells?

Back 121

first branchial pouch

Front 122

branchial source of epithelial lining of palatine tonsil?

Back 122

second branchial pouch

Front 123

branchial source of inferior parathyroids?

Back 123

third branchial pouch (dorsal wings)

Front 124

branchial source of thymus?

Back 124

third branchial pouch (ventral wings)

Front 125

branchial source of superior parathyroids?

Back 125

fourth branchial pouch (dorsal wings)

Front 126

cranial nerves involved with taste?

Back 126

CN VII, IX, X
(solitary nucleus)

Front 127

motor innervation of tongue?

Back 127

CN XII

Front 128

sensory innervation of tongue (pain)?

Back 128

CN V3, IX, X

Front 129

most common ectopic thyroid tissue site?

Back 129

tongue

Front 130

process leading to cleft lip?

Back 130

failure of fusion of maxillary and medial nasal processes (formation of primary palate)

Front 131

process leading to cleft palate?

Back 131

failure of fusion of lateral palatine processes, nasal septum, and/or median palatine process (formation of secondary palate)

Front 132

GI defect associated with trisomy 21?

Back 132

duodenal atresia (failure to recanalize)

Front 133

timing of midgut development?

Back 133

•6th week: midgut herniates through umbilical ring
•10th week: returns to abdominal cavity and rotates around SMA

Front 134

embryological orgin of spleen?

Back 134

arises from dorsal mesentary but supplied by artery of foregut

Front 135

three stages of kidney development?

Back 135

1. pronephros at week 4
2. mesonephros (interim kidney for first trimester, then contributes to male genital system)
3. metanephros (permanent) begins to appear during 5th week

Front 136

derivatives of mesonephric duct?

Back 136

(male internal structures)
Seminal vesicles
Epididymis
Ejaculatory duct
Ductus deferens

Front 137

derivatives of paramesonephric duct?

Back 137

(female internal structures)
fallopean tube
uterus
upper 1/3 of vagina

Front 138

congenital penile abnormality due to failure of urethral folds to close?

Back 138

hypospadias

Front 139

congenital penile abnormality due to faulty positioning of genital tubercle?

Back 139

epispadias; associated with exstrophy of bladder

Front 140

female remnant of gubernaculum?

Back 140

ovarian ligament and round ligament of uterus

Front 141

embryological origins of the diaphragm?

Back 141

Septum transversum
Pleuroperitoneal folds
Body wall
Dorsal mesentery of the esophagus

Front 142

boot shaped heart?

Back 142

Tetralogy of Fallot

Front 143

division of oocyte (into twins) between days 4-8?

Back 143

one placenta, two amnions, one chorion

Front 144

division of oocyte (into twins) between days 8-12?

Back 144

one placenta, one amnion, one chorion

Front 145

division of oocyte (into twins) within first three days?

Back 145

two placentas, two amnions, two chorions; can be mono- or di-zygotic twins

Front 146

germ cell layer source of anterior pituitary?

Back 146

(from Rathke's pouch)
surface ectoderm

Front 147

risk factor for patent ductus arteriosis?

Back 147

congenital rubella

Front 148

notched central incisors, blindness, deafness?

Back 148

congenital syphilis

Front 149

mental retardation, microcephaly, deafness?

Back 149

congenital CMV

Front 150

adult remnant of umbilical vein?

Back 150

ligamentum teres hepatis (contained within falciform ligament)

Front 151

adult remnant of ductus venosus?

Back 151

ligamentum venosum

Front 152

most common cardiac anomaly associated with Down's syndrome?

Back 152

atrial septal defect of septum primum