Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

121 Cards in this Set

  • Front
  • Back
sonic hedgehog gene
anterior-posterior axis
Wnt-7 gene
dorsal-ventral axis
FGF gene
lengthens limbs
homeobox gene
segmental organization
Rule of 2's for 2nd week
2 germ layers (bilaminar disk)=epiblast, hypoblast

2 cavities: amniotic, yolk sac

2 components to placenta: cytotrophoblast, syncytiotrophoblast
Rule of 3's for 3rd week
3 germ layers (gastrula): ecto, meso, endo
Rule of 4's for 4th week:
4 heart chambers (and it starts beating!!)

4 limb buds grow
benign Rathke's pouch tumor (surface ectoderm) with cholesterol crystals and calcifications.
Mesodermal defects = VACTERL
Vertebral defects
Anal atresia
Cardiac defects
Tracheo-esophageal fistula
Renal defects
Limb defects (bone AND muscle)
What do conjoined twins have that monozygotic twins DONT have?
1 amniotic sac.

monozygotic twins have 2! Note though that monozygotic twins can share an amniotic sac and not be conjoined but there is a risk of conjoined twins happening only when the amniotic sac is shared.
Most common teratogen that you should pick on every question and use it as a teaching tool to moms who are worried about teratogenic substances.

Not drinking alcohol is one of the very best things a pregnant woman can do.
part of chorion that secretes beta-hCG

outer layer of chorionic villi
What the f is the urachus and what does it develop from?
It is a duct between the bladder and yolk sac and forms from the allantois
What happens if the urachus doesn't obliterate? (2 issues)
1) patent urachus = urine discharge from umbilicus

2) Vesicourachal diverticulum= outpouching of bladder.
What is the vitelline duct?
connects yolk sac to midgut lumen... should be obliterated by week 7
What is a sign that a baby has a vitelline fistula?
Meconium discharge from the umbilicus... there was a FAILURE OF THE VITELLINE DUCT TO CLOSE
What is the timeline of fetal erythropoiesis? (locations and timing)
Young Liver Synthesizes Blood
1) Yolk sac until 8 weeks
2) Liver 6-30 weeks
3) Spleen 9-28 weeks
4) Bone marrow 28weeks onward
umbilical vein derivative
ligamentum teres hepatis
umbilical artery derivative
medial umbilical ligaments
ductus arteriosus
ligamentum arteriosum
ductus venosus
ligamentum venosum
foramen ovale
fossa ovalis
median ubilical ligament-- a urachal cyst or sinus is a remnant too
nucleus pulposus of intervertebral disk
telencephalon derivative
cerebral hemispheres

lateral ventricles are here
diencephalon derivative

3rd ventricle is here
mesencephalon derivative
Rhombencephalon makes up what
metencephalon and myelencephalon
metencephalon derivative
pons and cerebellum

4th ventricle
myelencephalon derivative

4th ventricle
What would be elevated in a mom's serum or amniotic fluid if she is carrying a baby with a neural tube defect?

Would be increased AFP and acetylcholinesterase in the CSF too (wikipedia says in the amniotic fluid too--acetylecholinesterase that is... so who knows just keep it in mind)
spina bifida occulta
failure of bony spinal canal to close, but no structural herniation usually seen at lower vertebral levels. Dura is intact.
enlargement of the central canal of spinal cord.

crossing fibers of spinothalamic tract typically damaged first.

cape-like, bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation.

Most common at C8-T1

often presents in pts with arnold-chiari II malformation
Think of the branchial arch innervation in terms of actions. Also remember the poem.
1) chewing, 2) facial expression, 3) stylopharyngeus, 4) swallowing, 6) speaking

One man sat chewing,
Two hands on his face.
The third with his pharynx swallowed the fourth plate.
"speak up, speak up!" Said the sixth in return. "Your cricothyroid makes me want to burn!"
Treacher Collins syndrome
1st arch neural crest fails to migrate leads to mandibular hypoplasia, facial abnormalities
Congenital pharyngocutaneous fistula
persistence of cleft and pouch which leads to fistula between tonsillar area, cleft in lateral neck

(arch 3 issue)
External auditory meatus develops from...
1st cleft
persistent cervical sinus results in what clinically?
branchial cleft cyst within lateral neck
inferior parathyroids develop from what?
3rd pouch
superior parathyroids develop from what?
4th pouch
What structures form the tongue and how can you rationalize knowing this?
anterior 2/3 from the 1st branchial arch innervated by CN V3 (sensation) and taste (CN VII)--remember the CN VII branch that enters the 1st arch

Posterior 1/3 is formed from the 3rd and 4th arches. Innervation is sensation and taste mainly CN IX with the extreme posterior via CN X) Makes sense with the arch derivations.
Where does the thyroid originate from?
It originates from the floor of the primitive pharynx and is connected to the tongue by the thyroglossal duct which often disappears but remants may remain as a htyroglossal duct cyst in the midline neck and will move with swallowing!!
Cleft lip cause
failure of fusion of the maxillary and medial nasal processes (formation of primary palate)
cleft palate cause
failure of fusion of the lateral palatine processes, the nasal septum, and / or the median palatine process (formation of secondary palate)
What are the 4 things that the diaphragm is derived from?
Several Parts Build Diaphragm
Septum Transversum (central tendon)
Pleuroperitoneal folds
Body Wall
Dorsal mesentery of esophagus (crura)
What clinical findings would you see in a baby born with an incomplete diaphragym?
hypoplasia of thoracic organs due to space compression, scaphoid abdomen, cyanosis
potter's syndrome cause and clinical presentation
Caused by malformation of ureteric bud.

babies who can't PEE in utero get this.

bilateral renal agenesis that leads to oligohydramnios in the amniotic sac thus limb deformities, facial deformities, and pulmonary hypoplasia due to the pressure imposed on the fetus without it's more billowy fluid cushion.
Cause of duodenal atresia
failure to recanalize (trisomy 21)
gastroschisis- cause and what is it?
Failure of lateral body folds to fuse

Extrusion of abdominal contents through abdominal folds
Omphalocele- cause and what is it?
persistance of herniation of abdominal contents into umbilical cord.

Abdominal contents will be covered by peritoneeum
What does failure of caudal fold closure cause?
bladder exstrophy
What does the midgut rotate around?
SMA... should go back in cavity at 10 weeks...
If there is a problem with this in any way there could be intestinal obstruction or twisting around SMA (volvulus)
What is the most common subtype of tracheoesophageal fistula? How does it present clinically?
Most common: blind upper esophagus with lower esophagus connected to the trachea.

Clinically: cyanosis, choking and vomiting with feeding, air bubble on CXR and polyhydramnios
Congenital pyloric stenosis: cause, clinical presentation, in whom is it most common
cause: hypertrophy of the pylorus causing obstruction

clinical: palpable "olive" sized mass in epigastric region and nonbilious projectile vomiting at around 2 weeks of age.

Occurs often in 1st born males, 1/600 live births.
What is an annular pancreas?
ventral pancreatic bud abnormally encircles 2nd part of duodenum; forms a ring of pancreatic tissue that may cause duodenal narrowing.
pancreas divisum
ventral and dorsal parts fail to fuse at 8 weeks
From what does the spleen arise from?
arises from the dorsal mesentary BUT is supplied by artery of foregut (celiac artery)
What is the most common site of obstruction in the fetus?
uteropelvic junction... it is the last to canalize and so the most likely spot of obstruction causing hydronephrosis in the fetus.
What does the mesonephric duct form?
Seminal vesicles
Ejaculatory Duct
Ductus deferens

Note that the prostate is NOT involved.
Cause of bicornate uterus
incomplete fusion of the paramesonephric ducts.

Associated with UT abnormalities and infertility
What is epispadias? What is the cause?
abnormal opening of penile urethra on the superior (dorsal) side of the penis.

It is due to faulty positioning of the genital tubercle.

Exstrophy of the bladder is associated with epispadias

(When you have epispadias you hit your EYE when you pee)
What is hypospadias? What is the cause?
Abnormal opening of penile urethra on inferior (ventral) side of penis due to failure of urethral folds to close.

More common than epispadias you fix it to prevent UTIs
What are the derivatives of the genital tubercle in females?
glans clitoris

vestibular bulbs
What are the derivatives of the genital tubercle in males?
glans penis

corpus cavernosum and spongiosum
What are the derivatives of the urogenital sinus in females
Greater vestibular glands of Bartholin

urethral and paraurethral glands of Skene
What are the derivatives of the urogenital sinus in males?
Bulbourethral glands (of Cowper)

Prostate Gland
What is the derivative of the urogenital folds in a female?
labia minora
What is the derivative of the urogenital folds in a male?
Ventral shaft of penis (penile urethra)
What is the derivative of the labioscrotal swelling in a female?
labia majora
What is the derivative of the labioscrotal swelling in a male?
truncus arteriosus becomes what
ascending aorta and pulmonary trunk
bulbus cordis becomes what
right ventricle and smooth parts (outflow tract) of left and right ventricle
primitive ventricle becomes
portion of the left ventricle
primitive atria becomes
trabeculated left and right atrium
left horn of sinus venosus (SV)
coronary sinus
right horn of sinus venosus
smooth part of right atrium
right common cardinal vein and right anterior cardinal vein
What divides the developing aorta and pulmonary trunk? What happens if this fails?
Neural crest cell migration. They divide the trunk into 2 arteries via fusion and twisting of truncal and bulbar ridges.

Transposition of great vessels and tetralogy of Fallot
1st aortic arch derivatives
part of maxillary artery (which is a branch of the external carotid)

1st arch is MAXimal
2nd aortic arch derivatives
Stapedial artery and hyoid artery

3rd aortic arch derivatives
common carotid arteries and proximal part of the internal carotid arteries

C is the 3rd letter of the alphabet. 3rd arch = carotid
4th aortic arch derivatives
on left, aortic arch
on right, proximal part of the right subclavian artery

4th arch (4 limbs) = systemic
6th aortic arch derivatives
proximal part of pulmonary arteries and (on left only) ductus arteriosus

6th arch = pulmonary and the pulmonary to systemic shunt (ductus arteriosus)
branchial clefts are derived from...
branchial arches are derived from...
mesoderm (muscles and arteries)

neural crest cells (bone and cartilage)
Branchial pouches are derived from...
CAP covers outside from inside (Branchial apparatus) which means...
Arches=mesoderm +neural crest
What are ACE inhibitors' effect on the fetus?
renal damage
What are alcohol's effect on the fetus?
leading cause of birth defects and mental retardation

fetal alcohol syndrome
What are alkylating agents' effect on the fetus?
absence of digits, multiple anomalies
What are aminoglycosides; effect on the fetus?
CN VIII toxicity
What is cocaine's effect on the fetus?
abnormal fetal development and fetal addition

placental abruption
What is Diethylstilbestrol's (DES) effect on the fetus?
vaginal clear cell adenocarcinoma
What are Folate Antagonists effect on the fetus?
neural tube defects
What is iodide's (lack or excess) effect on the fetus?
congenital goiter or hypothyroidism
What is Lithium's effect on the fetus?
Ebstein's anomaly (atrialized right ventricle)
What is Maternal Diabetes' effect on the fetus?
caudal regression syndrome (anal atresia to sirenomelia--mermaid syndrome)
What is smoking's (nicotine / CO) effect on the fetus?
preterm labor, placental problems, IUGR, ADHD
What are tetracyclines effects on the fetus?
discolored teeth
What is Thalidomide's effect on the fetus?
limb defects (flipper limbs)
What is Valproate's effect on the fetus?
inhibition of intestinal folate absorption-- neural tube defects
What is Vitamin A (in excess)'s effect on the fetus?
extremely high risk for spontaneous aboritons and birth defects (cleft palate, cardiac abnormalities)
What is warfarin's effect on the efetus?
bone deformities, fetal hemorrhage, abortion
What are x-ray and general anticonvulsants effects on the fetus
multiple anomalies
1st pouch develops into...
middle ear cavity, eustachian tube, mastoid air cells

**contributes to the endoderm-lined structions of the ear
2nd pouch develops into...
epithelial lining of the palatine tonsil
3rd pouch (dorsal wings) develops into...
inferior parathyroid

3rd pouch structures end up below 4th pouch structures
3rd pouch (ventral wings) develop into...
4th pouch (dorsal wings) develop into...
superior parathyroids.
What occurs when there is aberrant development of the 3rd and 4th branchial pouches?
DiGeorge Syndrome: leads to T cell deficiency (thymic aplasia) and hypocalcemia (failure of parathyroid development)
What causes MEN 2A?
mutation of germline RET (neural crest cells)

As a result you get
pheochromocytoma (adrenal medulla)
parathyroid tumor: 3rd/4th pouch
parafollicular cells that develop medullary thyroid cancer.. also derived from neural crest cells
1st branchial cleft develops into...
external auditory meatus
2nd through 4th clefts develop into...
temporary cerivcal sinuses that are obliterated by proliferation of 2nd arch mesenchyme that covers the rest of the clefts.
Branchial arch 1 nerve and artery derivatives
CN V2 and V3

Maxillary artery
Branchial arch 1 cartilage and muscle derivatives
Cartilage: meckel's cartilage, mandible, malleus, incus, sphenomandibular ligament

Muscules: muscles of mastication (temporalis, masseter, lateral and medial pterygoids), mylohyoid, anterior belly of the digastric, tensor tympani, tensor veli palatini, anterior 2/3 of tongue
Branchial arch 2 cartilage and muscle derivatives
Cartilage: Reichert's cartilage: stapes, styloid process, lesser horn of hyoid, stylohyoid ligament

Muscles: muslces of facial expression, Stapedium, Stylohyoid, posterior belly of digastric.
Branchial arch 2 nerve and artery derivatives

Stapedial artery, hyoid artery
Branchial arch 3 cartilage and muscle derivatives
Cartilage: greater horn of hyoid

Muscles: stylopharyngeus (think of stylopharyngeus innervated by glossopharyngeal nerve)
Branchial arch 3 nerve derivative
Branchial arch 4-6 cartilage and muscle derivatives
Cartilage: thyroid, cricoid, arytenoids, corniculate, cuneiform

4th arch: most pharyngeal constrictors, cricothyroid, levator veli palatini

6th arch: all intrinsic muscles of larynx except cricothyroid
Branchial arch 4-6 nerve derivatives
4th arch: CN X (superior laryngeal branch--SWALLOWING)

6th arch: CN X (recurrent laryngeal branch--SPEAKING)