REPRO EMBRYO Flashcards
What is the role of the sonic hedgehog gene in limb development?
It is located in the zone of polarizing activity and is involved in patterning along an anterior-posterior axis
Which gene, expressed in the zone of polarizing activity is involved in patterning along an anterior posterior axis?
Sonic Hedgehog
Which gene, expressed at the apical ectodermal ridge is responsible for patterning along a dorsal-ventral axis?
Wnt-7
What is the role of the Wnt-7 gene in limb development?
produced in apical ectodermal ridge and responsible for patterning on dorsal ventral axis
What gene is responsible for lengthening limbs?
FGF (mutation in FGF3 responsible for achondroplasia)
What is the role of FGF for limb development?
It is expressed in the apical ectodermal ridge and is responsible for lengthening the limbs
A mutation in which gene would result in a limb being in the wrong place (i.e. a leg where an arm should be)?
Hox genes
What is the role of Hox genes in fetal development?
They are responsible for segmental organization of the embryo in a craniocaudal way and can result in appendages being in the wrong place
What is present in the second week of gestation?
Bilaminar germ disc (epiblast and hypoblast)
When in gestation does hCG secretion start?
within week 1 (after implantation of blastocyst)
During which week does the fetal heart begin to beat?
Week 4 (also when all 4 limbs are present, at least as buds)
How does gastrulation initiate?
The epiblast of the bilaminar germ disc invaginates to form the primitive streak; gastrulation will form 3 germ layers
Which intracranial mass contains cholesterol crystals?
Craniopharyngioma from Rathke’s pouch (congential form =adamantinomatous; adult = papillary)
Where does the parotid gland come from?
surface ectoderm
Where does the lens of the eye come from? The retina and optic nerve?
lens = surface ectoderm; retina and optic nerve = neuroectoderm
Where do the parafollicular cells of the thyroid come from?
Neural crest
Where do pia and arachnoid cells come from embryologically?
Neural crest
Where does the aorticopulmonary septum come from?
Neural crest
Which organ is derived from the mesentery of the foregut?
Spleen
Where does the spleen come from, embryologically?
(Mesoderm; mesentery of the foregut)
A defect in which germ layer yields VACTERL anomaly?
mesoderm (Vertebral, Anal, Cardiac, Tracheo-Esophageal fistula, Renal, and Limb defects)
What germ layer is the notochord from? What is its embryological function?
Mesoderm; induces the ectoderm to form the neural plate (i.e. to become neuroectoderm)
What germ layer forms the eustachian tube?
Endoderm; it is from the 1st pharyngeal POUCH
What effect do ACE inhibitors have on the fetus?
Renal defects
What effect do alkylating agents have on a fetus?
absence of digits
What is the effect of aminoglycosides on fetus?
CN VIII toxicity (congenital syphilis has same etiology)
What effect does carbamazepine have on the fetus?
Neural tube defects, craniofacial defects, fingernail hypoplasia, developmental delay, IUGR
What effect does diethylstilbestrol have on the fetus?
Vaginal clear cell adenocarcinoma in future; congenital mullerian anomalies
What effect can lithium have on the fetus?
Ebstein’s anomaly (atrialization of the right ventricle)
A baby who has an atrialized right ventricle probably had a mother with what underlying condition?
Bipolar disorder, Ebstein’s anomaly is side effect of lithium.
Which drug is notable for causing Ebstein’s anomaly in the fetus?
Lithium
Which drug can cause fingernail hypoplasia and neural tube defects in fetus?
Carbamazepine
Which drug causes clear cell adenocarcinoma?
DES = Diethylstilbestrol
What can tetracylcines to the fetus?
Discolored teeth
What can thalidomide do to the fetus?
limb defects (phocomelia, amelia)