Create
Learn
Share

Embryo

rename
kirt147's version from 2012-06-13 02:38

Section 1

Question Answer
SHH gene does what?produced at base of limbs in zone of polarizing activity, patterns along anterior-posterior axis
defect in SHH gene causes what clinical presentation?holoprosenchephaly seen in trisomy 13
Wnt-7 gene located where, does what?apical ectodermal ridge (thickened ectoderm at distal end of developing limb) and does proper organization along dorsal-vental axis (remember things called ventral/dorsal DISTALLY)
FGF gene located where? does what?apical ectodermal ridge like Wnt-7 gene; stimulates mitosis of underlying mesoderm to lengthen limbs. Think GF= growth of limbs
Homeobox (HOX) gene helps with what?segmental organization of embryo in cranio-caudal direction
mutations in HOX cause what clinical presentation?polydactyly (extra fingers/toes), syndatyly (toes/fingers fused together)
most susceptible time for teratogensembryonic period weeks 3-8 b/c organs develop during this time
what invaginates to form the primitive streak?epiblast of bilaminar disk (precursor to ectoderm)
cells from primitive streak gives rise to what?intraembryonic mesoderm and part of endoderm
in general, what structures are derived from neural crest?PNS (ANS), DRG, CN's, odontoblasts (Crest toothpaste), bones of skull, pia and arachnoid, aorticopulmonary septum
what is a malformation?intrinsic disruption during embryonic period (wks 3-8)
what is a deformation?extrinsic disruption AFTER embryonic period
what is agenesis?absent primordial tissue so absent organ
what is hypoplasia?primordial tissue is there but the organ does not development completely
what is aplasia?primordial tissue is there but the organ does not develop AT ALL
AG's do what to babyototoxic
what does maternal diabetes do to fetus?caudal regression syndrome (anything from anal atresia to sirenomelia(mermaid syndrome))
alcohol does what to fetus?leading cause of birth defects and mental retardation, facial abnormalities
smoking does what to fetus?preterm baby, placental problems, IUGR, ADHD
tetracyclines do what to fetus?discolored teeth
thalidomide does what to fetus?limb defects ("flipper" limbs)
what does valproate do to fetus?inhibits intestinal folate absorption causing NTD's
what does excess vitamin A do to fetus?sp abortions, birth defects like cleft palate, cardiac abnormalities
what does warfarin do to fetus?bone deformities, fetal hemorrhage, abortion
twinning before day 3dichorionic, diamniotic, 2 placentas
twinning b/t days 3 and 8monochorion (b/c chorion already formed), diamniotic, 1 placenta
twinning after day 8monochorion, monoamnion (b/c amnion already formed), 1 placenta; risk of conjoined twins
what do you see clinically with patent urachus?urachus is duct b/t bladder and yolk sac, so get urine from your umbilicus
what is a vesicourachal diverticulum?bladder outpouches, but usually asx
what is a urachal sinus?distal part of urachus doesn't close, get purulent discharge, recurrent infections, and periumbilical tenderness
what is a urachal cyst?central part of urachus does not obliterate; get fluid filled structure b/t the two closed ends, usually asx
urachus is whatduct b/t bladder and yolk sac formed from allantois during 3rd week
vitteline ductconnects yolk sac to midgut lumen, should obliterate in 7th week
clinical sign of vitteline fistuladuct doesn't close so get poop out your umbilicus
bulbus cordis gives rise toRV and smooth parts(outflow tract) of L and RV
primitive ventricle gives rise totrabeculated parts of LV and RV
primitive atria gives rise totrabeculated parts of LA and RA
left horn of sinus venosus gives rise tocoronary sinus
right horn of sinus venosus gives rise tosmooth part of RA
right common cardinal vein and right anterior cardinal vein give rise toSVC
growth of endocardial tissues does whatseparates atria from ventricles and contributes to to both atrial separation and membraneous portion of the interventricular septum
valve of foramen ovale formed byseptum primum
opening in septum secondum is what?foramen ovale
locations of fetal erythropoiesisYoung Liver Synthesizes Blood: yolk sac-8 wk, liver-30 wk, spleen-28 week, BM after 28 week
blood from SVC goes where in fetus?into PA and then DA to lower body of fetus
memorize

Section 2

Question Answer
rhombencephalon becomes what?metencephalon (pons, cerebellum), and myelencephalon (medulla) and fourth ventricle
what is holoprosencephaly?hemispheres don't separate along the midline, get cyclops
what are characteristics of chiari II?stretches CN 9-11, syringomelia (STT cape-like pain and temperature loss), t-l myelomeningocele
what is a dandy walker?dilated fourth ventricle with posterior fossa cyst, absent cerebellar vermis
1st aortic arch formsmaxillary artery: 1st arch is MAXimal
2nd aortic arch formsStapedial a. and hyoid a. (Second forms Stapedial)
3rd aortic arch formsCommon carotid a., proximal part of internal carotid (C=3rd letter, 3rd arch)
4th aortic arch formsL: aortic arch, R: proximal part of R subclavian
6th aortic arch formsproximal part of pulmonary arteries and on left forms ductus arteriosus
what are the branchial clefts, arches, and pouches each derived from?wear a CAP covering outside to inside: ectoderm, mesoderm, endoderm
1st branchial cleft formsexternal auditory meatus
2nd-4th branchial clefts formtemporary cervical sinuses, but are obliterated by 2nd arch mesenchyme (otherwise get lateral persistent cervical sinus/branchial cleft cyst)
memorize

Branchial Arches

Question Answer
1st branchial archMeckel's cartilage, Mandible, Malleus, incus, spenoMandibular ligament, Muscles of Mastication, Mylohyoid, anterior belly digastric, tensor tympani, tensor veli pelatini, anterior 2/3 tongue
nerve from 1st branchial archV2 and V3
Treacher Collins syndrome1st branchial arch neural crest fails to migrate
2nd branchial archStapes, Styloid process, Stylohyoid ligament, lesser horn of hyoid, muscles of facial expression, Stapedius, Stylohyoid, posterior belly digastric
nerve from 2nd brancheal arch7
3rd branchial arch greater horn of hyoid, stylopharyngeus
nerve from 3rd branchial archglossopharyngeal (CN 9)
4th-6th branchial archthyroid, cricoid, etc., 4th for pharyngeal constrictors, cricothyroid, levator veli palatini; 6th for intrinsic muscles of larynx EXCEPT cricothyroid
nerves of 4th and 6th branchial arch4th- CN 10; superior laryngeal branch for swallowing; 6th- CN 10; recurrent laryngeal nerve for speaking
congenital pharyngo-cutaneous fistulapersistence of 3rd cleft and pouch...fistula b/t tonsillar area and cleft in lateral neck
memorize

Branchial Pouches

Question Answer
1st pouchmiddle ear cavity, eustacian tube, mastoid air cells
2nd pouchepithelial lining of palantine tonsil
3rd pouchdorsal wings-inferior PT, ventral wings-thymus
4th pouchdorsal wings-superior PT
memorize

More Embryo

Question Answer
normal remnant of thyroglossal duct isforamen cecum
cleft lip formed fromfailed fusion of maxillary and medial nasal processes (during formation of primary palate)
cleft palate formed fromfailed fusion of lateral palantine processes, nasal septum, and/or the median palantine processes (during formation of secondary palate)
sternal defects due to failure ofrostral fold closure
bladder exstrophy due to failure ofcaudal fold closure
duodenal atresia due to failure torecanalize
jejunal, ileal, colonic atresia due tovascular accident (gives apple peel atresia)
failure of lateral fold closure forms what (2)gastroschisis, omphalocele
what can malrotation of midgut around SMA cause?intestinal obstruction from adhesion bands, or volvulus ischemia from twisting around blood vessels
not being able to put NG tube into stomach, choking, air bubble in stomach tells you what?tracheoesophageal fistula, upperesophageal atresia and lower esophagus connected to trachea
dorsal and ventral pancreatic buds together formhead, main pancreatic duct
ventral body alone formsuncinate process
dorsal pancreatic bud becomeseverything else (body, tail, isthmus, accessory pancreatic duct)
annular pancreas formed from theventral pancreatic bud
what is different about the spleen?derived from dorsal mesentery (is from mesoderm) but supplied by artery of foregut (celiac)
what forms the permanent kidney?metanephros
ureteric bud becomesureter, pelvis, calyces, collecting ducts (the collecting system really)
metanephric mesenchymeglomerulus, renal tubules to distal convoluted tubule
most common cause of hydronephrosis in fetusobstruction at uteropelvic jxn b/c last to canalize
Potter's syndrome is due to malformation ofureteric bud (which gives rise to collecting system)
memorize

Genital Embryo

Question Answer
urogenital sinus in males becomesprostate gland and bulbourethral glands of cowper
urogenital sinus in females becomesgreater vestibular glands of bartholin and urethral and paraurethral glands of skene
urogenital fold in males becomesventral shaft of penis (penile urethra)
urogenital fold in females becomeslabia majora
genital tubercle in females becomesclitoris and vestibular bulbs
genital tubercle in males becomesglans penis and corpus cavernosum and spongiosum; faulty positioning causes epispadias
what is asst'd with epispadiasExstrophy of bladder (part of bladder present outside of the body)
female remnant of gubernaculum isovarian ligament and round ligament of the uterus
memorize