Fa Embryology Usmle

Front 1

When does implantation occur

Back 1

within week 1

Front 2

When does the bilaminar disk form?

Back 2

within week 2

Front 3

When do the primitive streak, notochord and neural plate begin to form?

Back 3

within week 3

Front 4

when do the neural tube form and organogenesis occur?

Back 4

between weeks 3 and 8

Front 5

During what time period is the fetus most susceptible to teratogens?

Back 5

embryologic period; between weeks 3 and 8

Front 6

When do the limb buds begin to form?

Back 6

week 4

Front 7

When does the heart begin to beat?

Back 7

week 4

Front 8

when does the fetus look like a baby and begin to move?

Back 8

week 8

Front 9

when is the earliest one can tell the sex of the baby?

Back 9

genitalia have male/female characteristics by week 10

Front 10

the alar plate forms what part of the peripheral nervous system?

Back 10

sensory

Front 11

the basal plate forms what part of the peripheral nervous system?

Back 11

motor

Front 12

rule of 2's for 2nd week?

Back 12

2 germ layers: epiblast, hypoblast
2 cavities: amniotic cavity, yolk sac
2 components to placenta: cytotrophoblasat, syncytiotrophoblast

Front 13

rule of 3's for 3rd week?

Back 13

3 germ layers (gastrula): ectoderm, mesoderm, endoderm

Front 14

rule of 4's for 4th week?

Back 14

4 heart chambers, 4 limb buds

Front 15

from whence is the intraembryonic mesoderm and endoderm derived?

Back 15

primitive streak (from the epiblast)

Front 16

what structures come from the surface ectoderm?

Back 16

adenohypophysis; lens of eye; epithelial linings of skin, ear, eye, nose; epidermis

Front 17

what structures come from the neuroectoderm?

Back 17

neurohypophysis, CNS neurons, oligodendrocytes, astrocytes, ependymal cells, pineal gland

Front 18

Which structures come from the neural crest?

Back 18

ANS, dorsal root ganglia, melanocytes, chromaffin cells of adrenal mudulla, enterochromaffin cells, pia and arachnoid, celiac ganglion Schwann cells, odontoblasts, parafollicular cells of thyroid, laryngeal cartilage, bones of skull

Front 19

what structures arise from the endoderm?

Back 19

gut tube epithelium and derivatives (lungs, liver, pancreas, thymus, parathyroid, thyroid follicular cells)

Front 20

what structures come from the mesoderm?

Back 20

dura mater, connective tissue, muscle, bone, cardiovascular structures, lymphatics, blood, urogenital structures, serous linings of body cavities, spleen, adrenal cortex, kidneys

Front 21

neural plate formation is induced by what?

Back 21

notochord

Front 22

the notochord forms what postnatal structure?

Back 22

nucleus pulposus

Front 23

fetal alcohol exposure causes what?

Back 23

retardation, microcephaly, facial abnormalities, limb dislocation ,heart and lung fistulas

Front 24

fetal exposure to ACE inhibitors results in what?

Back 24

renal damage

Front 25

fetal exposure to cocaine results in what?

Back 25

abnormal fetal development and addiction

Front 26

fetal DES exposure causes what?

Back 26

vaginal clear cell carcinoma

Front 27

fetal iodide exposure causes what?

Back 27

congenital goiter or hypothyroidism

Front 28

fetal thalidomide exposure causes what?

Back 28

limb defects (flipper arms) lack of limb bud development

Front 29

what is the function of the urachus?

Back 29

to remove nitrogenous waste from the fetal bladder

Front 30

from what structure are the umbilical arteries and veins derived?

Back 30

allantois

Front 31

truncus arteriosus gives rise to what?

Back 31

ascending aorta and pulmonary trunk

Front 32

the bulbus cordis gives rise to what structures?

Back 32

smooth parts of left and right ventricle

Front 33

the primitive ventricle is analogous to what structure in the adult heart?

Back 33

trabeculated parts of left and right ventricle

Front 34

the primitive atria give rise to what structures?

Back 34

trabeculated left and right atrium

Front 35

the left horn of the sinus venosus gives rise to what structure?

Back 35

coronary sinus

Front 36

the right horn of the sinus venosus gives rise to what structure?

Back 36

smooth part of right atrium

Front 37

right common cardinal vein and right anterior cardinal vein give rise to what structure in the adult?

Back 37

SVC

Front 38

when does the bone marrow begin erythropoiesis?

Back 38

week 28

Front 39

when is the yolk sac most responsible for erythropoiesis?

Back 39

weeks 3-8

Front 40

what structure(s) is/are responsible for erythropoiesis during weeks 8-28?

Back 40

Liver (wk 6-30) and Spleen (wk 9-28)

Front 41

the ligamentum teres hepatis is a remnant of what embryologic structure?

Back 41

umbilical vein

Front 42

in what adult structure is the ligamentum teres hepatis contained?

Back 42

falciform ligament

Front 43

the medial umbilical ligaments are derived from what embryonic structure?

Back 43

umbilical arteries

Front 44

the ligamentum arteriosum is derived from what embryonic structure?

Back 44

ductus arteriosus

Front 45

the ligamentum venosum is derived from what embryonic structure?

Back 45

ductus venosus

Front 46

the median umbilical ligament is derived from what embryonic structure?

Back 46

allantois/urachus

Front 47

the nucleus pulposus of intervertebral disks are derived from what embryonic structure?

Back 47

notochord

Front 48

1st aortic arch gives rise to what structure?

Back 48

maxillary artery

Front 49

3rd aortic arch gives rise to what structures?

Back 49

common carotid artery and proximal part of internal carotid artery

Front 50

2nd aortic arch gives rise to what structure?

Back 50

stapedial artery and hyoid artery

Front 51

4th aortic arch gives rise to what structures?

Back 51

left: aortic arch
right: proximal part of right subclavian artery

Front 52

6th aortic arch gives rise to what structure?

Back 52

proximal part of pulmonary arteries and ductus arteriosus

Front 53

Derivatives of branchial arch 1?

Back 53

Meckel's cartilage: Mandible, Malleus, incus, sphenoMandibular ligament
Muscles: Muscles of Mastication, Mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini, anterior 2/3 of tongue
Nerves: CN V2 and V3

Front 54

branchial arch 2 derivatives?

Back 54

Reichert's cartilage: Stapes, Styloid process, lesser horn of hyoid, Stylohyoid ligament
Muscles: facial expression, Stapedius, Stylohyoid, posterior belly of digastric
Nerves: CN VII

Front 55

what is derived from branchial arch 3?

Back 55

greater horn of hyoid, stylopharyngeus muscle glossopharyngeal nerve

Front 56

branchial arches 4-6 derive what structures?

Back 56

thyroid, cricoid, arytenoid, corniculate, cuneiform cartilages; pharyngeal constrictor muscles, cricothyroid, levator veli palatini (4th), intrinsic muscles of larynx (6th, except cricothyroid); CNX; posterior 1/3 of tongue

Front 57

which cranial nerves have both sensory and motor components?

Back 57

V2, V3, VII, IX, X

Front 58

What is the embryologic origin of the external auditory meatus?

Back 58

1st branchial cleft

Front 59

What structures are derived from the 1st pharyngeal pouch?

Back 59

middle ear cavity, eustachan tube, mastoid air cells

Front 60

what structures are derived from the 2nd pharyngeal pouch?

Back 60

epithelial lining of palatine tonsil

Front 61

what structures are derived from the 3rd pharyngeal pouch?

Back 61

inferior parathyroids from dorsal wings; thymus from ventral wings

Front 62

what structures are derived from the 4th pharyngeal pouch?

Back 62

superior parathyroids

Front 63

The diaphragm is derived from what embryologic structures?

Back 63

Septum transversum, Pleuroperitoneal folds, Body wall, Dorsal mesentery of esophagus

Front 64

what structures form the foregut?

Back 64

pharynx to duodenum

Front 65

what structures form the midgut?

Back 65

duodenum to transverse colon

Front 66

what structures are in the hindgut?

Back 66

distal transverse colon to rectum

Front 67

what is gastroschisis?

Back 67

failure of lateral body folds to fuse --> extrusion of abdominal contents through abdominal folds --> not covered by membrane

Front 68

what is an omphalocele?

Back 68

persistence of herniation of abdominal contents into umbilical cord --> contents covered by membrane

Front 69

from what tissue is the spleen derived?

Back 69

dorsal mesentery

Front 70

What hormone stimulates gonadal differentiation to the testes?

Back 70

TDF

Front 71

What hormone causes regression of the paramesonephric ducts in males?

Back 71

mullerian inhibiting factor

Front 72

what hormone stimulates the growth of the mesonephric ducts in males?

Back 72

testsosterone

Front 73

what hormone stimulates regression of mesonephric ducts in females?

Back 73

lack of testosterone

Front 74

the mesonephric ducts form what structures in the normal male?

Back 74

ductus deferens, epididymis, efferent ductules

Front 75

what hormone stimulates growth of the paramesonephric ducts in females?

Back 75

lack of MIF

Front 76

paramesonephric ducts form what structures in the normal female?

Back 76

fallopian tube, uterus, upper 1/3 of vagina

Front 77

what embryologic structures form the scrotum and labia majora?

Back 77

genital swellings

Front 78

what embryologic structures form the labia minora?

Back 78

urethral folds

Front 79

what hormone causes secondary sexual maturation in males?

Back 79

Dihydrotestosterone (DHT)

Front 80

what embryologic structure forms the clitoris in females?

Back 80

genital tubercle

Front 81

deficiency in 5-alpha-reductase causes what?

Back 81

lack of DHT in males, so there is no secondary sexual differentiation. Testes and internal genitalia are established, but external genitalia are ambiguous

Front 82

metanephric duct develops into what structures?

Back 82

ureter, renal pelvic and collecting system

Front 83

urogenital sinus develops into what structures?

Back 83

bladder; prostate and bulbourethral glands in males; lower 2/3 of vagina and hymen in females

Front 84

initially what are the layers of the chorionic villi?

Back 84

syncitium, cytotrophoblast, connective tissue, endothelium

Front 85

what are the layers of the mature chorionic villi?

Back 85

syncytium, endothelium