Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
282 Cards in this Set
- Front
- Back
sonic hedgehog gene
|
produced at base of limbs in zone of polarizing activity
involved in patterning along anterior-posterior axis |
|
Wnt-7 gene
|
produced at apical ectodermal ridge (thickened ectoderm at distal end of each developing limb)
necessary for proper organization along dorsal-ventral axis |
|
FGF gene
|
produced at apical ectodermal ridge
stimulates mitosis of underlying mesoderm, providing for lengthening of limbs |
|
homeobox (Hox) genes
|
involved in segmental organization of embryo in a craniocaudal direction
Hox mutations lead to appendages in wrong locations |
|
fetal landmarks at day 0
|
fertilization by sperm forming a zygote, initiating embryogenesis
|
|
fetal landmarks within week 1
|
hCG secretion begins after implantation of blastocyst
|
|
fetal landmarks within week 2
|
bilaminar disk (epiblast, hypoblast)
|
|
fetal landmarks within week 3
|
trilaminar dic
gastrulation primitive streak, notochord, mesoderm, and its organization neural plate begins to form |
|
fetal landmarks between weeks 3 and 8 (embryonic period)
|
neural tube formed by neuroectoderm and closes by week 4
organogenesis fetus is extremely susceptible to teratogens |
|
fetal landmarks during week 4
|
heart begins to beat
upper and lower limb buds begin to form |
|
fetal landmarks during week 8 (fetal period)
|
fetal movement
fetus looks like a baby |
|
fetal landmarks during week 10
|
genitalia have male/female characteristics
|
|
alar plate
|
dorsal
sensory same orientation as spinal cord |
|
basal plate
|
ventral
motor same orientation as spinal cord |
|
when does a fertilized egg become a zygote?
|
day 2
|
|
when does a fertilized egg become a morula?
|
day 3
|
|
when does a fertilized egg become a blastocyst?
|
day 5
|
|
when does a fertilized egg become implanted?
|
day 6
|
|
what induces ectoderm to differentiate into neuroectoderm and form the neural plate?
|
the notochord induces overlying ectoderm to differentiate into neuroectoderm to form the neural plate
|
|
what does the neural plate give rise to?
|
neural tube
neural crest cells |
|
what does the notochord become in adults?
|
it becomes the nucleus pulposus of the intervertebral disk in adults
|
|
what is the rule of 2's for the second week of early development?
|
2 germ layers (bilaminar disk):
- epiblast - hypoblast 2 cavities: - amniotic cavity - yolk sac 2 components to placenta: - cytotrophoblast - syncytiotrophoblast |
|
what happens to the epiblast?
|
the epiblast is the precursor to ectoderm
it invaginates to form the primitive streak, which gives rise to both intraembryonic mesoderm and part of the endoderm |
|
what is the rule of 3's for the third week of early development?
|
3 germ layers (gastrula):
- ectoderm - mesoderm - endoderm |
|
what is the rule of 4's for the fourth week of early development?
|
4 heart chambers
4 limb buds grow |
|
what are the embryologic derivatives of the surface ectoderm?
|
1. adenohypophysis (from Rathke's pouch)
2. ocular lens 3. epithelial linings of oral cavity, sensory organs of ear, and olfactory epithelium 4. epidermis 5. anal canal below pectinate line 6. salivary, sweat, mammary glands |
|
what is a craniopharyngioma?
|
benign Rathke's pouch tumor with cholesterol crystals and/or calcifications
|
|
from what embryologic germ layer is the adenohypophysis derived?
|
surface ectoderm
(derived from Rathke's pouch) |
|
from what embryologic germ layer is the lens of the eye derived?
|
surface ectoderm
|
|
from what embryologic germ layer is the epithelial lining of the oral cavity derived?
|
surface ectoderm
|
|
from what embryologic germ layer is the epithelial lining of the sensory organs of the ear derived?
|
surface ectoderm
|
|
from what embryologic germ layer is the olfactory epithelium derived?
|
surface ectoderm
|
|
from what embryologic germ layer is the epidermis derived?
|
surface ectoderm
|
|
from what embryologic germ layer is the anal canal derived (below the pectinate line)?
|
surface ectoderm
|
|
from what embryologic germ layer are the salivary glands derived?
|
surface ectoderm
|
|
from what embryologic germ layer are the sweat glands derived?
|
surface ectoderm
|
|
from what embryologic germ layer are the mammary glands derived?
|
surface ectoderm
|
|
what are the embryologic derivatives of neuroectoderm?
|
brain
- neurohypophysis - CNS neurons - oligodendrocytes - astrocytes - ependymal cells - pineal gland retina spinal cord neuroectoderm - think CNS and brain |
|
what are the embryologic derivatives of neural crest?
|
autonomic nervous system
dorsal root ganglia cranial nerves celiac ganglion melanocytes chromaffin cells of adrenal medulla parafollicular (C) cells of thyroid Schwann cells pia mater and arachnoid bones of the skull odontoblasts aorticopulmonary septum neural crest - think PNS and non-neural structures nearby |
|
from what embryologic germ layer is the autonomic nervous system derived?
|
neural crest
|
|
from what embryologic germ layer are the dorsal root ganglia derived?
|
neural crest
|
|
from what embryologic germ layer are the cranial nerves derived?
|
neural crest
|
|
from what embryologic germ layer is the celiac ganglion derived?
|
neural crest
|
|
from what embryologic germ layer are melanocytes derived?
|
neural crest
|
|
from what embryologic germ layer are chromaffin cells of the adrenal medulla derived?
|
neural crest
|
|
from what embryologic germ layer are parafollicular (C) cells of the thyroid derived?
|
neural crest
|
|
from what embryologic germ layer are Schwann cells derived?
|
neural crest
|
|
from what embryologic germ layer are the pia mater and arachnoid mater derived?
|
neural crest
|
|
from what embryologic germ layer are the bones of the skull derived?
|
neural crest
|
|
from what embryologic germ layer are odontoblasts derived?
|
neural crest
remember: odonto = teeth - think CREST toothpaste |
|
from what embryologic germ layer is the aorticopulmonary septum derived?
|
neural crest
|
|
what are the embryologic derivatives of endoderm?
|
gut tube epithelium:
- anal canal above the pectinate line derivatives: - lungs - liver - pancreas - thymus - parathyroid - thyroid follicular cells |
|
what is the acronym for mesodermal defects?
|
VACTERL
V-ertebral defects A-nal atresia C-ardiac defects T-racheoEsophageal fistula R-enal defects L-imb defects (bone and muscle) |
|
what are the embryologic derivatives of mesoderm?
|
muscle
bone connective tissue serous linings of body cavities spleen (derived from foregut mesentery) cardiovascular structures lymphatics blood bladder urethra vagina eustachian tube kidneys adrenal cortex skin dermis testes ovaries |
|
from what embryologic germ layer is the gut tube epithelium derived?
|
endoderm
**includes anal canal above the pectinate line** |
|
from what embryologic germ layer are the lungs derived?
|
endoderm
|
|
from what embryologic germ layer is the liver derived?
|
endoderm
|
|
from what embryologic germ layer is the pancreas derived?
|
endoderm
|
|
from what embryologic germ layer is the thymus derived?
|
endoderm
|
|
from what embryologic germ layer are the parathyroid glands derived?
|
endoderm
|
|
from what embryologic germ layer are the thyroid follicular cells derived?
|
endoderm
|
|
from what embryologic germ layer is muscle derived?
|
mesoderm
|
|
from what embryologic germ layer is bone derived?
|
mesoderm
|
|
from what embryologic germ layer is connective tissue derived?
|
mesoderm
|
|
from what embryologic germ layer is the serous lining of body cavities (e.g. peritoneum) derived?
|
mesoderm
|
|
from what embryologic germ layer is the spleen derived?
|
mesoderm
**derived from foregut mesentery** |
|
from what embryologic germ layer are the cardiovascular structures derived?
|
mesoderm
|
|
from what embryologic germ layer are the lymphatics derived?
|
mesoderm
|
|
from what embryologic germ layer is blood derived?
|
mesoderm
|
|
from what embryologic germ layer is the urethra derived?
|
mesoderm
|
|
from what embryologic germ layer is the vagina derived?
|
mesoderm
|
|
from what embryologic germ layer are the eustachian tubes derived?
|
mesoderm
|
|
from what embryologic germ layer are the kidneys derived?
|
mesoderm
|
|
from what embryologic germ layer are the adrenal cortices derived?
|
mesoderm
|
|
from what embryologic germ layer is the skin dermis derived?
|
mesoderm
|
|
from what embryologic germ layer are the testes derived?
|
mesoderm
|
|
from what embryologic germ layer are the ovaries derived?
|
mesoderm
|
|
what is the postnatal derivative of the notochord?
|
nucleus pulposus of the intervertebral disk
|
|
malformation
|
intrinsic disruption in organ morphogenesis
occurs during the embryonic period (weeks 3-8) |
|
deformation
|
extrinsic disruption in organ morphogenesis
occurs after the embryonic period |
|
agenesis
|
absent organ due to absent primordial tissue
|
|
hypoplasia
|
incomplete organ development
primordial tissue is present |
|
aplasia
|
absent organ despite presence of primordial tissue
|
|
teratogens
|
fetus is most susceptible in the 3rd to 8th weeks of pregnancy (embryonic period, during organogenesis)
before week 3 there is an all-or-none effect after week 8 only growth and function are affected |
|
teratogenic effects of ACE inhibitors
|
renal damage
|
|
teratogenic effects of alkylating agents
|
absence of digits
multiple anomalies |
|
teratogenic effects of aminoglycosides
|
CN VIII toxicity
remember: A MEAN GUY hit the baby in the ear |
|
teratogenic effects of carbamazepine
|
neural tube defects
craniofacial defects fingernail hypoplasia developmental delay IUGR |
|
teratogenic effects of diethylstilbestrol (DES)
|
vaginal clear cell adenocarcinoma in the fetus
|
|
teratogenic effects of folate antagonists
|
neural tube defects
|
|
teratogenic effects of lithium
|
Ebstein's anomaly (atrialized right ventricle)
|
|
teratogenic effects of phenytoin
|
fetal hydantoin syndrome
microcephaly dysmorphic craniofacial features hypoplastic nails hypoplastic distal phalanges cardiac defects IUGR mental retardation |
|
teratogenic effects of tetracyclines
|
discolored teeth
|
|
teratogenic effects of thalidomide
|
limb defects ("flipper" limbs)
LIMB defects with tha-LIMB-domide |
|
teratogenic effects of valproic acid
|
inhibition of maternal folate absorption leading to neural tube defects
|
|
teratogenic effects of warfarin
|
bone deformities
fetal hemorrhage abortion ophthalmologic abnormalities do not wage WARFARE on the baby; keep it HEPPY with HEParin (does not cross the placenta) |
|
teratogenic effects of alcohol abuse
|
leading cause of birth defects and mental retardation
fetal alcohol syndrome |
|
teratogenic effects of cocaine
|
abnormal fetal development and fetal addiction
placental abruption |
|
teratogenic effects of smoking (nicotine, CO)
|
preterm labor
placental problems IUGR ADHD |
|
teratogenic effects of iodide (lack or excess)
|
congenital goiter or hypothyroidism
|
|
teratogenic effects of maternal diabetes
|
caudal regression syndrome (anal atresia to sirenomelia)
congenital heart defects neural tube defects |
|
teratogenic effects of excess vitamin A
|
extremely high risk for spontaneous abortions and birth defects
- cleft palate - cardiac abnormalities |
|
teratogenic effects of X-rays
|
microcephaly
mental retardation |
|
fetal alcohol syndrome
|
leadicng cause of congenital malformations in US
newborns of mothers who consumed significant amounts of alcohol during pregnancy have an inc. incidence of congenital abnormalities (pre- and postnatal developmental retardation, microcephaly, holoprosencephaly, facial abnormalities, limb dislocation, heart/lung fistulas) mechanism may include inhibition of cell migration |
|
what is the leading cause of congenital malformations in the United States?
|
fetal alcohol syndrome
|
|
dizygotic twins
|
arise from 2 separate eggs that are separately fertilized by two different sperm
**ALWAYS two zygotes** twins are dichorionic and diamniotic |
|
monozygotic twins
|
arise from 1 fertilized egg (1 egg + 1 sperm) that splits into two zygotes in early pregnancy
degree of separation depends on when the fertilized egg splits into two zygotes timing of this separation determines the number of chorions and number of amnions |
|
what is the result of eggs splitting between 0 and 4 days after fertilization?
|
cleavage between the two cell stage and the morula
occurs in 25% of twins placenta can be fused or can be separate; twins are dichorionic and diamniotic |
|
what is the result of eggs splitting between 4 and 8 days after fertilization?
|
cleavage between the morula stage and blastocyst stage
occurs in 75% of twins twins are monochorionic and diamniotic |
|
what is the result of eggs splitting between 8 and 12 days after fertilization?
|
cleavage between the blastocyst stage and the stage with a formed embryonic disc
occurs in <1% of twins twins are monochorionic and monoamniotic |
|
what happens if a fetus is cleaved more than 13 days after fertilization?
|
twins are monochorionic, monoamniotic, and conjoined
|
|
what is the primary site of nutrient and gas exchange between a mother and fetus?
|
placental development
|
|
fetal component of the placenta
|
cytotrophoblast - inner layer of chorionic villi (Cyto makes Cells)
syncytiotrophoblast - outer layer of chorionic villi - secretes hCG |
|
what is hCG?
|
human chorionic gonadotropin
hormone that is structurally similar to LH stimulates corpus luteum to secrete progesterone during the first trimester |
|
maternal component of the placenta
|
decidua basalis - derived from the endometrium
maternal blood is in lacunae |
|
what vascular structures are found in the umbilical cord?
|
2x umbilical arteries
- return deoxygenated blood from fetal internal iliac arteries to placenta 1x umbilical vein - supplies oxygenated blood from placenta to fetus - drains into IVC |
|
where does the umbilical vein drain?
|
inferior vena cava (IVC)
|
|
with what is a single umbilical artery associated?
|
congenital and chromosomal anomalies
|
|
from where are the umbilical arteries and veins derived?
|
allantois
|
|
urachal duct development
|
3rd week - yolk sac forms allantois, which extends into urogenital sinus
allantois becomes urachus, a duct between the bladder and the yolk sac |
|
urachal duct abnormalities
|
failure of urachus to obliterate:
1. patent urachus - urine discharge from umbilicus 2. vesicourachal diverticulum - outpouching of bladder |
|
vitelline duct development
|
the vitelline duct connects the yolk sac to the midgut lumen
in the 7th week, the vitelline (omphalomesenteric) duct is obliterated |
|
vitelline duct abnormalities
|
1. vitelline fistula - failure of duct to close, leading to meconium discharge from umbilicus
2. meckel's diverticulum - partial closure, with patent portion attached to ileum; pt may have ectopic gastric mucosa leading to melena and periumbilical pain |
|
meckel's diverticulum
|
partial closure of the vitelline duct, with the patent portion attached to the ileum
pt may have ectopic gastric mucosa leading to melena and periumbilical pain |
|
to what structures does the truncus arteriosus (TA) give rise?
|
ascending aorta
pulmonary trunk |
|
to what structures does the bulbus cordis give rise?
|
right ventricle
smooth parts (outflow tracts) of left and right ventricles |
|
to what structures does the primitive ventricle give rise?
|
trabeculated left and right ventricles
|
|
to what structures does the primitive ventricle give rise?
|
trabeculated left and right atria
|
|
to what structures does the left horn of the sinus venosus (SV) give rise?
|
coronary sinus
|
|
to what structures does the right horn of the sinus venosus (SV) give rise?
|
smooth part of right atrium
|
|
to what structures do the right common cardinal vein and right anterior cardinal vein give rise?
|
superior vena cava (SVC)
|
|
formation of truncus arteriosus
|
neural crest migration leads to truncal and bulbar ridges that spiral and fuse to form the aorticopulmonary septum
this then develops into the ascending aorta and pulmonary trunk |
|
pathology of truncus arteriosus
|
1. transposition of great vessels (failure to spiral)
2. tetralogy of Fallot (skewed aorticopulmonary septum development) 3. persistent truncus arteriosus (partial aorticopulmonary septum development) |
|
steps of interventricular septum development
|
1. muscular septum forms (opening is called interventricular foramen)
2. aorticopulmonary septum meets and fuses with muscular ventricular septum to form membranous IV septum, closing the IV foramen 3. growth of endocardial cushions separates atria from ventricles and contributes to both atrial separation and membranous portion of the IV septum |
|
pathology of interventricular septum development
|
improper neural crest migration into the truncus arteriosus can result in transposition of the great arteries or a persistent truncus arteriosus
membranous septal defect causes initial left-to-right shunting, which then becomes right-to-left shunting (Eisenmenger's syndrome) |
|
Eisenmenger's syndrome
|
membranous septal defect in the IV septum causes initial left-to-right shunting, which then becomes right-to-left shunting
|
|
stages in the development of the interatrial septum
|
1. foramen primum narrows as septum primum grows toward endocardial cushions
2. perforations in septum primum form foramen secundum (foramen primum disappears) 3. foramen secundum maintains right-to-left shunt as septum secundum begins to grow 4. septum secundum contains a permanent opening (foramen ovale) 5. foramen secundum enlarges and upper part of septum primum degenerates 6. remaining portion of septum primum forms valve of foramen ovale 7. septum secundum and septum primum fuse to form the atrial septum 8. foramen ovale usually closes soon after birth because of inc. left atrial pressure |
|
pathology of interatrial septum
|
patent foramen ovale, which is caused by excessive resorption of septum primum and/or secundum
|
|
where does fetal erythropoiesis occur?
|
Yolk sac (3-8 wks)
Liver (6-30 wks) Spleen (9-28 wks) Bone marrow (>28 wks) remember: Young Liver Synthesizes Blood |
|
what are the globin groups in fetal hemoglobin?
|
2 alpha subunits
2 gamma subunits |
|
what are the globin groups in adult hemoglobin?
|
2 alpha subunits
2 beta subunits |
|
what is the O2 saturation of blood in the umbilical vein?
|
about 80%
|
|
what is the O2 saturation of blood in the umbilical artery?
|
very, very low
|
|
what are the three important shunts in fetal circulation?
|
1. ductus venosus (umbilical vein to IVC; bypass hepatic circulation)
2. foramen ovale (right atrium to left atrium; bypass pulmonary circulation) 3. ductus arteriosus (pulmonary artery to aorta; bypass pulmonary circulation) |
|
ductus venosus
|
blood entering the fetus through the umbilical vein is conducted via the ductus venosus into the IVC to bypass the hepatic circulation
|
|
foramen ovale
|
most oxygenated blood reaching the heart via the IVC is diverted through the foramen ovale and pumped out the aorta to the head and body
|
|
ductus arteriosus
|
deoxygenated blood from the SVC is expelled into the pulmonary artery and ductus arteriosus to the lower body of the fetus
|
|
what happens to the three fetal shunts at birth?
|
infant takes a breath leading to dec. resistance in pulmonary vasculature
decreased resistance in the pulmonary vasculature then leads to increased left atrial pressure vs. right atrial pressure foramen ovale closes (now called fossa ovalis) inc. O2 leads to dec. prostaglandins, causing closure of ductus arteriosus |
|
what drug can be used to force closure of a patent ductus arteriosus?
|
indomethacin
|
|
what drug can be used to maintain a patent ductus arteriosus?
|
prostaglandins (PGE2 specifically)
|
|
what is the postnatal derivative of the umbilical vein?
|
ligamentum teres hepatis
(it is contained in the falciform ligament) |
|
what is the postnatal derivative of the umbiLical arteries?
|
mediaL umbilical ligaments
|
|
what is the postnatal derivative of the ductus arteriosus?
|
ligamentum arteriosum
|
|
what is the postnatal derivative of the ductus venosus?
|
ligamentum venosum
|
|
what is the urachus?
|
the part of the allantoic duct between the bladder and the umbilicus
|
|
what is the postnatal derivative of the foramen ovale?
|
fossa ovalis
|
|
what is the postnatal derivative of the allantois?
|
allaNtois is the urachus-mediaN umbilical ligament
|
|
what is a remnant of the allantois?
|
urachal cyst or sinus
|
|
what is the postnatal derivative of the notochord?
|
nucleus pulposus of the intervertebral disc
|
|
what are the three primary vesicles of the developing brain?
|
1. forebrain (prosencephalon)
2. midbrain (mesencephalon) 3. hindbrain (rhombencephalon) |
|
what are the five secondary vesicles of the developing brain (from what primary vesicle do they each derive)?
|
1. telencephalon (prosencephalon/forebrain)
2. diencephalon (prosencephalon/forebrain) 3. mesencephalon (mesencephalon) 4. metencephalon (rhombencephalon/hindbrain) 5. myelencephalon (rhombencephalon/hindbrain) |
|
what are the adult derivatives of the telencephalon?
|
walls develop into the cerebral hemispheres
cavity develops into the lateral ventricles |
|
what are the adult derivatives of the diencephalon?
|
walls develop into the thalamus
cavity develops into the third ventricle |
|
what are the adult derivatives of the mesencephalon?
|
walls develop into the midbrain
cavity develops into the aqueduct of silvius |
|
what are the adult derivatives of the metencephalon?
|
walls develop into the pons and the cerebellum
cavity develops into the upper part of the fourth ventricle |
|
what are the adult derivatives of myelencephalon?
|
walls develop into the medulla
cavity develops into the lower part of the fourth ventricle |
|
from what vesicles do the cerebral hemispheres derive?
|
primary vesicle: forebrain/prosencephalon
secondary vesicle: telencephalon (walls) |
|
from what vesicles do the lateral ventricles derive?
|
primary vesicle: forebrain/prosencephalon
secondary vesicle: telencephalon (cavity) |
|
from what vesicles does the thalamus derive?
|
primary vesicle: forebrain/prosencephalon
secondary vesicle: diencephalon (walls) |
|
from what vesicles does the third ventricle derive?
|
primary vesicle: forebrain/prosencephalon
secondary vesicle: diencephalon (cavity) |
|
from what vesicles is the midbrain derived?
|
primary: midbrain/mesencephalon
secondary: mesencephalon (walls) |
|
from what vesicles is the aqueduct of silvius derived?
|
primary: midbrain/mesencephalon
secondary: mesencephalon (cavity) |
|
from what vesicles is the pons derived?
|
primary: hindbrain/rhombencephalon
secondary: metencephalon (walls) |
|
from what vesicles is the cerebellum derived?
|
primary: hindbrain/rhombencephalon
secondary: metencephalon (walls) |
|
from what vesicles is the upper part of the fourth ventricle derived?
|
primary: hindbrain/rhombencephalon
secondary: metencephalon (cavity) |
|
from what vesicles is the medulla derived?
|
primary: hindbrain/rhombencephalon
secondary: myelencephalon (walls) |
|
from what vesicles is the lower part of the fourth ventricle derived?
|
primary: hindbrain/rhombencephalon
secondary: myelencephalon (cavity) |
|
neural tube defects
|
neuropores fail to fuse in the fourth week causing persistent connection between the amniotic cavity and the spinal canal
associated with low folic acid intake during pregnancy elevated alpha-fetoprotein (AFP) in amniotic fluid as well as in maternal serum elevated AFP and acetylcholinesterase in the amniotic fluid b/c it leaks out of the CSF |
|
spina bifida occulta
|
failure of bony spinal canal to close, though there is no structural herniation
usually seen at lower vertebral levels; usually a tuft of hair sits over the defect dura is intact |
|
meningocele
|
meninges herniate through spinal canal defect
|
|
meningomyelocele
|
meninges and spinal cord herniate through a spinal cord defect
|
|
anencephaly
|
malformation of the anterior end of the neural tube
pt has no brain/calvarium, has elevated alpha-fetoprotein, and polyhydramnios no swallowing center in the brain |
|
holoprosencephaly
|
decreased separation of hemispheres across the midline
results in cyclopia associated with Patau's syndrome (trisomy 13), severe fetal alcohol syndrome, and cleft lip/palate |
|
what are the forebrain anomalies?
|
anencephaly
holoprosencephaly |
|
what are the posterior fossa malformations?
|
Chiari II
Dandy-Walker |
|
Chiari II
|
cerebellar tonsillar herniation through the foramen magnum with aqueductal stenosis and hydrocephaly
often presents with syringomyelia and thoraco-lumbar myelomeningocele |
|
what is syringomyelia?
|
disorder in which a cyst or cavity, called a syrinx, forms within the spinal cord
it can expand and elongate over time, destroying the spinal cord, possibly resulting in pain, paralysis, weakness, and stiffness in the back, shoulders, and extremities may also cause a loss of the ability to feel extremes of hot or cold, especially in the hands. generally leads to a cape-like loss of pain and temperature sensation along the back and arms |
|
Dandy-Walker syndrome
|
large posterior fossa
absent cerebellar vermis with cystic enlargement of the fourth ventricle can lead to hydrocephalus and spina bifida |
|
syringomyelia
|
enlargement of the central canal of the spinal cord
crossing fibers of the spinothalamic tract are typically damaged first presents as a "cape-like" bilateral loss of pain and temp sensation in upper extremities with preservation of touch sensation syrinx = tube, as in syringe associated with Chiari II malformation most common at C8-T1 |
|
what is derived from the first aortic arch?
|
part of the MAXillary artery (branch of the external carotid artery)
1st arch is MAXimal |
|
what is derived from the second aortic arch?
|
Stapedial artery and hyoid artery
Second = Stapedial |
|
what is derived from the third aortic arch?
|
common Carotid artery
proximal part of internal carotid artery remember: C is the third letter of the alphabet |
|
what is derived from the fourth aortic arch?
|
- on left, the aortic arch
- on right, the proximal part of the right subclavian artery 4th arch (4 limbs) = systemic |
|
what is derived from the sixth aortic arch?
|
proximal part of the pulmonary arteries and (on left only) ductus arteriosus
6th arch = pulmonary and pulmonary-to-systemic shunt (ductus arteriosus) |
|
where does the right recurrent laryngeal nerve loop around?
|
4th aortic arch
proximal part of right subclavian artery |
|
where does the left recurrent laryngeal nerve loop around?
|
6th aortic arch
ductus arteriosus and subsequently the aorta |
|
what are the components of the branchial apparatus?
|
branchial clefts
branchial arches branchial pouches CAP covers outside from inside Clefts = ectoderm Arches = mesoderm Pouches = endoderm |
|
branchial clefts
|
part of the branchial apparatus
derived from ectoderm also called branchial grooves |
|
branchial arches
|
part of the branchial apparatus
derived from mesoderm (muscle, arteries) and neural crests (bones, cartilage) |
|
branchial pouches
|
part of the branchial apparatus
derived from endoderm |
|
branchial cleft derivatives
|
1st cleft develops into external auditory meatus
2nd through 4th clefts form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme persistent cervical sinus leads to branchial cleft cyst within the lateral neck |
|
cartilage derivatives of the first branchial arch
|
Meckel's cartilage:
- Mandible - Malleus - incus - sphenoMandibular ligament |
|
muscle derivatives of the first branchial arch
|
Muscles of Mastication
- temporalis - Masseter - lateral and Medial pterygoids Mylohyoid anterior belly of digastric tensor tympani tensor veli palatini |
|
nerves derived from first branchial arch
|
CN V2 and V3
remember: chew |
|
Treacher Collins syndrome
|
first arch neural crest fails to migrate leading to mandibular hypoplasia and facial abnormalities
|
|
cartilage derivatives of the second branchial arch
|
Reichert's cartilage:
- Stapes - Styloid process - lesser horn of hyoid - Stylohyoid ligament |
|
muscle derivatives of the second branchial arch
|
muscles of facial expression
Stapedius Stylohyoid posterior belly of digastric |
|
nerve derivatives of the second branchial arch
|
CN VII (facial expression)
smile |
|
cartilage derivatives of the third branchial arch
|
greater horn of the hyoid
|
|
muscle derivatives of the third branchial arch
|
stylopharyngeus
remember: stylo-PHARYNGEUS is innervated by the glossoPHARYNGEAL nerve |
|
nerve derivatives of the third branchial arch
|
CN IX (stylopharyngeus)
SWALLOW STYLishly |
|
congenital pharyngocutaneous fistula
|
persistence of the third branchial cleft and pouch creating a fistula between the tonsillar area and the cleft in lateral neck
|
|
cartilage derivatives of the 4-6th branchial arches
|
thyroid cartilage
cricoid cartilage arytenoids corniculate cartilage cuneiform cartilage |
|
muscle derivatives of the 4th branchial arch
|
- most pharyngeal constrictors
- cricothyroid muscle - levator veli palatini |
|
muscle derivatives of the 6th branchial arch
|
all intrinsic muscles of the larynx except the cricothyroid
|
|
nerve derivatives the 4th branchial arch
|
CN X (superior laryngeal branch)
SIMPLY SWALLOW |
|
nerve derivatives of the 6th branchial arch
|
CN X (recurrent laryngeal branch)
SPEAK |
|
what branchial arches form the posterior third of the tongue?
|
arches 3 and 4
|
|
what are the developmental contributions of the 5th branchial arch?
|
arch 5 makes no major developmental contributions
|
|
what are the only cranial nerves with both motor and sensory components?
|
CN V3
CN VII CN IX CN X |
|
what is the acronym for the branchial arches?
|
when at the golden ARCHES, children tend to first CHEW (1), then SMILE (2), then SWALLOW STYLishly (3) or SIMPLY SWALLOW (4), and then SPEAK (6)
|
|
what are the derivatives of the 1st branchial pouch?
|
middle ear cavity
eustachian tube mastoid air cells contributes to endoderm-lined structures of the ear |
|
what are the derivatives of the 2nd branchial pouch?
|
epithelial lining of the palatine tonsil
|
|
what are the derivatives of the 3rd branchial pouch?
|
dorsal wings develop into inferior parathyroids
ventral wings develop into thymus 3rd pouch contributes to 3 structures (thymus, left and right inferior parathyroids) 3rd pouch structures end up below 4th pouch structures |
|
what are the derivatives of the 4th branchial pouch?
|
dorsal wings develop into superior parathyroids
|
|
what is the acronym for the derivatives of the branchial pouches?
|
ear, tonsils, bottom-to-top:
1. contributes to endoderm-lined structures of the ear 2. contributes to epithelial lining of palatine tonsil 3. dorsal (bottom for inferior parathyroids) 3. ventral (to = thymus) 4. dorsal (top for superior parathyroids) |
|
what results from aberrant development of the third and fourth branchial pouches?
|
DiGeorge syndrome
- cell deficiency (thymic aplasia) - hypocalcemia (failure of parathyroid development) |
|
Multiple Endocrine Neoplasia (MEN) 2A
|
associated with germline mutation of RET (affects neural crest cells)
- adrenal medullary tumor (pheochromocytoma) - parathyroid (tumor): 3rd/4th pharyngeal pouch - parafollicular cells (medullary thyroid cancer): derived from neural crest cells; associated with 4th/5th pharyngeal pouches |
|
tongue development
|
1st branchial arch forms anterior 2/3
- sensation via CN V3 - taste via CN VII 3rd and 4th branchial arches form posterior 1/3 - sensation and taste mainly via CN IX - in extreme posterior, it is via CN X |
|
what nerve is responsible for motor innervation of the tongue?
|
CN XII
|
|
from where are the muscles of the tongue derived?
|
occipital myotomes
|
|
nerves responsible for taste, pain, and motor innervation of the tongue
|
taste:
- CN VII in front 2/3 - CN IX in posterior 1/3 - CN X in extreme posterior pain: - CN V3 in front 2/3 - CN IX in posterior 1/3 - CN X in extreme posterior motor: - CN XII |
|
thyroid development
|
thyroid diverticulum arises from floor of primitive pharynx and descends into the neck
connected to tongue by thyroglossal duct, which normally disappears but may persist as pyramidal lobe of thyroid foramen cecum is normal remnant of thyroglossal duct |
|
what is the most common site for ectopic thyroid tissue?
|
tongue
|
|
thyroglossal duct cyst
|
midline neck cyst that moves with swallowing
vs. persistent cervical sinus leading to branchial cleft cyst in lateral neck |
|
cleft lip
|
failure of fusion of the maxillary and medial nasal processes (formation of primary palate)
**often occurs with cleft palate** |
|
cleft palate
|
failure of fusion of the lateral palatine processes, the nasal septum, and/or the median palatine process (formation of secondary palate)
**often occurs with cleft lip** |
|
what are the segments of the GI tract?
|
1. foregut (pharynx to duodenum)
2. midgut (duodenum to transverse colon) 3. hindgut (distal transverse colon to rectum) |
|
what are the causes of developmental defects of the anterior abdominal wall?
|
failure of:
- rostral fold closure: sternal defects - lateral fold closure: omphalocele, gastroschisis - caudal fold closure: bladder exstrophy |
|
duodenal atresia
|
failure to recanalize
associated with trisomy 21 |
|
jejunal, ileal, colonic atresia
|
due to vascular accident
"apple peel atresia" |
|
midgut development
|
6th week - midgut herniates through umbilical ring physiologically
10th week - midgut returns to abdominal cavity and rotates around superior mesenteric artery |
|
pathology of midgut development
|
malrotation of midgut
omphalocele intestinal atresia or stenosis volvulus |
|
gastroschisis
|
extrusion of abdominal contents through abdominal folds
not covered by peritoneum |
|
omphalocele
|
persistence of herniation of abdominal contents into umbilical cord
covered by peritoneum |
|
tracheoesophageal fistula
|
abnormal connection between esophagus and trachea
most common subtype is blind upper esophagus with lower esophagus connected to trachea (type C) presentation: - cyanosis - choking/vomiting with feeding - air bubble in stomach on CXR - polyhydramnios - failure to pass NG tube into stomach - pneumonitis |
|
congenital pyloric stenosis
|
hypertrophy of the pylorus that causes obstruction
presentation: - palpable "olive" mass in epigastric region - nonbilious projectile vomiting at about two weeks of age treatment: - surgical incision epidemiology: - 1/600 live births - often in 1st born males |
|
pancreatic embryology
|
derived from foregut
dorsal and ventral pancreatic buds contribute to the pancreatic head and main pancreatic duct uncinate process is formed by the ventral bud alone dorsal pancreatic bud becomes body, tail, isthmus, accessory pancreatic duct ventral and dorsal buds fuse at 8 weeks |
|
annular pancreas
|
ventral pancreatic bud abnormally encircles 2nd part of the duodenum
forms a ring of pancreatic tissue that may cause duodenal narrowing |
|
pancreas divisum
|
ventral and dorsal pancreatic buds fail to fuse at 8 weeks
|
|
embryology of the spleen
|
arises from dorsal mesentery (thus mesodermal origin)
supplied by artery of foregut (celiac artery) |
|
kidney embryology
|
development of the kidney proceeds through a series of successive phases, each marked by the development of a more advanced kidney: the pronephros, mesonephros, and metanephros
- pronephros is the most immature form of kidney - metanephros is most developed - metanephros persists as the definitive adult kidney |
|
what stage of the kidney persists as the definitive adult kidney?
|
metanephros
|
|
pronephros
|
first stage of kidney development
most immature form of kidney develops in the cervical region of the embryo develops in week 4 and then degenerates |
|
mesonephros
|
functions as interim kidney for first trimester
later contributes to male genital system |
|
metanephros
|
permanent
beginnings first appear during the 5th week of gestation; nephrogenesis continues through 32-36 weeks of gestation most mature kidney stage |
|
ureteric bud
|
derived from caudal end of mesonephros
gives rise to ureter, pelvises, and calyces/collecting ducts (through branching) fully canalized by the 10th week |
|
metanephric mesenchyme
|
ureteric bud interacts with this tissue
interaction induces differentiation and formation of glomerulus and renal tubules to distal convoluted tubule aberrant interaction btwn this and ureteric buds may result in several congenital malformations |
|
what is the most common site of obstruction (hydronephrosis) in a fetus?
|
ureteropelvic junction with the kidney (it is the last to canalize)
|
|
Potter's syndrome
|
bilateral renal agenesis leading to oligohydramnios leading to limb deformities, facial deformities, and pulmonary hypoplasia
caused by malformation of ureteric bud babies who can't "Pee" in utero develop Potter's syndrome |
|
horseshoe kidney
|
inferior poles of both kidneys fuse
as they ascend from the pelvis during fetal development, horseshoe kidneys get trapped under inferior mesenteric artery and remain low in the abdomen kidney functions normally associated with Turner syndrome (XO) |
|
female genital embryology
|
default development
mesonephric duct degenerates and paramesonephric duct develops |
|
male genital embryology
|
SRY gene on Y chromosome produces testis-determining factor (testes development)
Mullerian inhibitory factor from Sertoli cells suppresses development of paramesonephric ducts increased androgens from Leydig cells stimulates development of mesonephric ducts mesonephric duct must be induced to remain; default program for embryo development is for paramesonephric duct to develop into female |
|
what is the gubernaculum?
|
slender band, extending from that part of the skin of the groin which afterward forms the scrotum through the inguinal canal to the body and epididymis of the testis
|
|
mesonephric (Wolffian) duct
|
develops into male internal structures (except prostate)
- S-eminal vesicles - E-pididymis - E-jaculatory duct - D-uctus deferens remember: SEED |
|
paramesonephric (Mullerian) duct
|
develops into female internal structures
- fallopian tubes - uterus - upper 1/3 of vagina Mullerian duct abnormalities result in anatomical defects that may present as primary amenorrhea in females with fully developed secondary sexual characteristics (indicator of functional ovaries) |
|
bicornuate uterus
|
results from incomplete fusion of the paramesonephric ducts
associated with urinary tract abnormalities and infertility |
|
5alpha-reductase deficiency
|
male internal genitalia
ambiguous external genitalia until puberty |
|
SRY gene
|
SRY gene on Y chromosome causes production of testis-determining factor, which leads to testes development
sertoli cells of the testes produce anti-mullerian hormone which causes degeneration of paramesonephric (mullerian) duct (female internal genitalia) Leydig cells produce testosterone which causes male internal genitalia to develop from Wolffian ducts; testosterone is converted to DHT by 5alpha reductase, which then causes the genital tubercle and urogenital sinus to develop into male external genitalia and a prostate |
|
what is the result of a lack of sertoli cells or a lack of anti-Mullerian hormone?
|
develop both male and female internal genitalia
develop male external genitalia |
|
what are the adult derivatives of the genital tubercle?
|
in men: glans penis, corpus cavernosum, corpus spongiosum (via DHT)
in women: glans clitoris, vestibular bulbs (via estrogen) |
|
what are the adult derivatives of the urogenital sinus?
|
in men: bulbourethral glands (of Cowper), prostate gland
- via DHT in women: greater vestibular glands (of Bartholin), urethral and paraurethral glands (of Skene) - via estrogen |
|
what are the adult derivatives of the urogenital folds?
|
in men: ventral shaft of penis (penile urethra)
- via DHT in women: labia minora |
|
what are the adult derivatives of the labioscrotal swelling?
|
in men: scrotum (via DHT)
in women: labia majora (via estrogen) |
|
hypospadias
|
abnormal opening of penile urethra on inferior (ventral) side of the penis due to failure of the urethral folds to close (remember: HYPO is below)
hypospadias are more common than epispadias fix hypospadias to prevent UTIs |
|
epispadias
|
abnormal opening of penile urethra on superior (dorsal) side of penis due to faulty positioning of genital tubercle
Exstrophy of the bladder is associated with Epispadias remember: when you have Epispadias, you hit your Eye when you pEE |
|
what is exstrophy of the bladder?
|
congenital anomaly in which part of the urinary bladder is present outside the body
|
|
what is the female remnant of the gubernaculum?
|
ovarian ligament and round ligament of the uterus
|
|
what is the male remnant of the gubernaculum?
|
band of fibrous tissue that anchors testes within the scrotum
|
|
what is the female remnant of the processus vaginalis?
|
N/A
the processus vaginalis is obliterated |
|
what is the male remnant of the processus vaginalis?
|
tunica vaginalis
|
|
what is the processus vaginalis?
|
evagination of peritoneum
|