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33 Cards in this Set
- Front
- Back
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Function and location of Sonic hedgehog gene?
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Produced at base of limbs in ZPA. involved in patterning along anterior-posterior axis.
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Function and location of Wnt-7 Gene?
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Produced @ apical ectodermal ridge (thickened ectoderm at distal end of each developing limb). Necessary for proper organization along dorsal-ventral axis.
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Function and location of FGF gene
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produced at apical ectodermal ridge. Stimulates mitosis of underlying mesoderm, providing for lengthening of limbs.
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Function and location of Homeobox gene?
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involved in segmental organization.
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What is derived from neuroectoderm?
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Brain, retinal, and spinal cord.
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What is derived from the neural crest?
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"PNS and non-neural structures nearby"
ANS, dorsal root ganglia, CN's, celiac ganglion, melanocytes, chromaffin cells of adrenal medulla, enterochromaffin cells, parafollicular cells of thyroid, Schwann cells, pia and arachnoid, bones of the skull, odontoblasts, laryngeal cartilage, aorticopulmonary septum. |
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What is derived from the surface ectoderm?
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Adenohypophysis (from Rathke's pouch), lens of eye, epithelial linings of oral cavity, sensory organs of ear, retina, and olfactory epithelium; epidermis; salivary sweat, and mammary glands.
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What is derived from endoderm?
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Gut tube epithelium and derivatives (e.g. lungs, liver, pancreas, thymus, parathyroid, thyroid follicular cells)
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what is derived from mesoderm?
Mesodermal defects have a mnemonic, what is it? |
muscle, bone, connective tissue, serious linings of body cavities (e.g. peritoneum), spleen (derived from foregut mesentery), cardiovascular structure, lymphatics, blood, urogenital structures, kidneys, adrenal cortex.
VACTERL Vertebral, Anal atresia, Cardiac defects, Tracheo0-Esophageal fistula, Renal defects, Limb defects (bone and muscle). |
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What is the rule for the 2nd week of development?
3rd? 4th? |
2's:
- 2 germ layers (bilaminar disk) = epiblast and hypoblast - 2 cavities = amniotic cavity, yolk sac - 2 components to placenta = cytotrophoblast, syncytiotrophoblast 3's - 3 germ layers (gastrula) = ectoderm, mesoderm, endoderm 4's: - 4 ht chambers - 4 limb buds grow |
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What is the most susceptible period of teratogens?
- why? - defects afterward lead to what? |
3rd-8th week
- organogenesis - growth and fx are affected. |
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What are some of the defects seen with FAS?
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pre- and post-natal developmental retardation, microcephaly, holoprosencephaly, facial abnormalities, limb dislocation, and heart and lung fistulas.
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What day is the chorion formed? Amnion?
What is the story w/ monozygotic twins? - how does time of split play into # of placenta/chorions? - split post-8d puts at risk for what and why? - what would a split b/t 3 and 8d give you? - before 3 days? Dizygotic twins? |
3 = chorion
8 = amnion 1 zygote splits. - splitting after/before these landmarks determines what you get. - at risk for conjoined twins b/c they're sharing the same placenta, amnion, and chorion. - monozygotic, monochorionic twins, diamniotic twins with one placenta. - monozygotic, dichorionic, diamniotic twins with one placenta. Dizygotic twins have 2 of everything --> they're two different fertilized eggs, after all! |
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Which portion of the placenta secretes hCG?
- part of fetal or maternal placenta? - stim what during the 1st trimester? - what part of the placenta is it? Use words. |
Synctiotrophoblast
- fetal - hCG secretion stims the corpeus luteum to secrete progesterone during the first trimester. - it's the outermost layer of the chorionic vili sticking into the sea of maternal blood. |
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What comprises the inner layer of chorionic villi?
- fx? |
cytotrophoblast.
- makes cells. (Cyto makes Cells). |
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What is the name for the maternal component of the placenta?
- derived from what? What supplies the maternal blood to the lacunae? |
decidua basalis
- endometrium Maternal arteries (maternal veins take it away) |
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Give me the functions and number of the umbilical artery(s) and umbilical vein(s).
What other structure is in the umbilical cord? - when does it form? - forms from what? |
2 umbillical arteries, carry deoxygenated blood from fetal internal iliac arteries to placenta
1 umbilical vein, carries oxygenated blood from placenta to fetus. Urachus - 3rd wk - yolk sac forms allantois, which extends into urogenital sinus... allantois becomes urachus, a duct between bladder and yolk sac. |
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What defect results in urine discharge from umbilicus post-birth?
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patent urachus
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What is a vesicourachal diverticulum?
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outpouching of bladder.
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What is Meckel's diverticulum?
- sx @ presentation post birth? |
partial closure of the vitelline duct, which connects the developing midgut lumen to the yolk sac. It's supposed to obliterate completely ~ the 7th wk.
Mekel's is when it fails to close all the way, and the patent portion is attached to ileum. ectopic gastric mucosa --> melana and RUQ pain. |
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Discharge meconium from umbilicus is due to?
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Vitelline fistula. Vitilline duct that usully joins developing midgut to yolk sac doesn't close all the way. Example ~ Meckel's diverticulum.
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Given the following embryonic structures, give me what they give rise to:
- Truncus arteriosus - Bulbus cordis - primitive ventricle - primitive atria - left horn of sinus venosus (SV) - right horn of SV - Right common cardinal vein and right anterior cardinal vein. |
- Ascending aorta and pulmonary trunk
- right ventricle and smooth parts (outflow tract) of left and right ventricle - portion of the left ventricle - traveculated left and right atrium - coronary sinus - smooth part of right atrium - SVC |
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What happens to the Truncus arteriosus?
- pathology of this process leads to... |
neural crest cells migrate in, and divide trunk into 2 arteries via fusion and twisting of truncal and bulbar ridges --> ascending aorta and pulmonary trunk.
- TGA, or Tet of Fallot |
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Location of fetal erythropoiesis in wks:
- 3-8wks? - 6-30wks? - 9-28wks? - 28wks onward? |
"Young Liver Synths Blood"
- yolk sac - liver - spleen - BM |
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What are the three important shunts?
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1. Ductus venousus takes oxy blood from umbilical vein PAST hepatic circulation and into IVC.
2. most oxy blood reaching fetal ht thru IVC R-->L thru foramen ovale. 3. Deoxy blood from SVC is expelled inot the pulmonary artery and the ductus arteriosis to the lower body of fetus. |
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At birth, walk thru the process that closes the PDA.
- what can help this along? - what can hold it off? |
Infant takes breath --> \\pulmonary vascular resistance --> ^^LAP vs RAP which pushes the flap of foramen ovale closed. Increase in O2 leads to \\in prostaglandins, which makes the ductus arteriosus close.
- indomethacin (NSAID) - prostaglandins |
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What is the post-natal remnant of:
- umbilical vein? - umbilical arteries? - ductus arteriosus - ductus venosus - foramen ovale - allantois/urachus? - notochord? |
- ligamentum teres hepatis
- umbiLicaL ~ mediaL umbilical ligament - ligamentum arteriosum - ligamentum venosum - fossa ovalis - allaNtois ~ mediaN umbilical ligament - nucleus pulposis of IV discs. |
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What are the derivitives of the following structures:
- 1st AA - 2nd AA - 3rd AA - 4th AA - 5th AA |
- part of MAXillary artery (a branch of external carotid) [first arch is "MAXimal"]
- *S*econd ~ Stapedial artery and hyoid artery - C is 3rd letter of alphabet ~ common *C*arotid artery and proximal part of internal carotid artery - "4th arch ~ 4 limbs ~ systemic" on left, aortic arch; on right, proximal part of right subclavian - "pulmonary (proximal part of pulmonary arteries) and the pulmonary-to-systemic shunt (ductus-arteriosus)" |
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Give me the segments, walls, and cavities derived from the following initial brain regions:
- Prosencephalon - Mesencephalon - Rhombencephalon |
- Telencephalon --> walls (cerebral hemispheres); cavities (lateral ventricles)
- Diencephalon --> walls (thalami, etc.); cavities (3rd ventricle) - -------- --> walls (midbrain), cavities (aqueduct) - Metencephalon --> walls (pons and cerebellum); cavities (4th ventricle... and the pons part helps with the aqueduct) - Myelencephalon --> walls (medulla), cavities (----) |
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Elevated lvls of which two things can indicate a NTD?
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alpha fetoprotein (AFP)
Acetylcholinesterase |
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What is holoprosencephaly?
- associated with which 3 things? anencephaly? |
\\separation of the hemispheres across midline; results in cyclopia. Associated with Patau's syndrome (trisomy 13 due to nondisjuntion), severe FAS, and cleft-lip/palate.
malformatio of anterior end of neural tube; no brain/calvarium. Elevated AFP, polyhydramnios = excess of amniotic fluid. No swallowing center seen in brain. |
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What are the two types of posterior fossa malformations we should know? Describe them.
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cerebellar tonsillar herniation through foramen magnum w/ aqueductal stenosis and hydrocephaly. [Arnold-Chiari type II]. Often presents with fluild in the spinal cord leading to damage (syringomyelia), and/or thoracolumbar myelomeningocele.
Large posterior fossa; absent cerebellar vermis with cystic enlargement of the 4th ventricle. [Dandy-Walker] can lead to hydrocephalus and spina bifida. |
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What do we call an enlargement of the central canal of spinal cord?
- which fibers are typically damaged first? - presenting sx? what is preserved? - often assoc. w/ which malformation? - most common at which lvls? |
Syringomyelia
- crossing fivers of spinothalamic tract. - "cape-like" bilateral loss of pain and temperature sensation in upper extremities with preservation of touch sensation. - arnold-chiari II malformation - C8-T1 |
