Anderson Review Qns Flashcards
In early heart formation, cells migrating through the anterior part of the primitive streak will form which of the components of the heart?
forms outflow tract
In the early embryo, during somitogenesis, how many somitomere pairs are found caudal to the most caudal somite pair?
1st pair of somites forms behind (caudal to) 7th pair of somitomeres at the expense of the 8th pair of somitomeres
-11 pairs of somitomeres kept constant at caudal end of paraxial mesoderm
Opposing FGF-8 and retinoic acid gradients associated with which theory regarding somite formation?
wavefront or determination front model of somitogenesis
The sclerotome is derived from cells from what source?
paraxial mesoderm
what is the source of the cardiogenic plate?
splanchnic mesoderm
An inductive stimulus from what source stimulates the transformation of the epithelial sclerotome into secondary mesenhcyme?
notochord
What type of embryonic defects are characterized as primary errors of morphogenesis that are usually multifactorial and involve a number of etiological agents including genetic and environmental factors?
malformations
What condition refers to the accumulation of edema fluid in the fetus during intauterine growth?
hydrops
Folic acid deficiency is now thought to be a major cause of what class of malformations?
neural tube defects
Anal atresia can be attributed to what type of disturbance?
disturbance in tissue resorption
What group of congenital malformations makes up the largest percentage of congenital malformations?
UNKNOWN FACTORS
The intermediate mesoderm in the early embryo gives rise to which system(s)/structures?
urogenital system
Cleft palate is the result of a defect in what developmental mechanism?
failure to fuse
Phocomelia is most likely to be seen after maternal exposure to which teratogenic agent during the first trimester of pregnancy?
Thalidomide
What are the characteristic effects caused by exposure of the fetus to alcohol?
-growth and mental retardation
-microcehaly
-face and trunk malformations
- heart defects
holoprosencephaly=severe
Supplementing the diet of women of childbearing age with which dietary supplement may reduce the incidence of neural tube defects such as anencepahly?
folic acid
In fetal hydrops, the affected brain may become enlarged and edamatous and, when sectioned, has a bright yellow color, particularly the bsal nuclei, thalamus, cerebellum, cerebral gray, and spinal cord. What term is related to this CNS damage?
kernicturus
An increased incidence of what conditions is strongly associated with increasing maternal age?
trisomy 21
During childbirth, which membranes/layers around the embryo rupture and which do not?
layers that rupture-amnion and chorion
layers that don’t rupture—>allantois and secondary umbilical vesicle
Tendons of limb muscles arise from what source?
lateral plate mesoderm
Limb muscles arise from what source?
ventrolateral dermomyotome
Expression of what genes are involved in the separation of the dermomyotome into dorsal dermatome and ventral myotome?
expression of Pax 3, Pax 7, and Paraxis
In early heart formation, cells migrating through the middle part of the primitive streak will form which of the hearts components?
form ventricles
In early heart formation, cells migrating through the anterior part of the primitive streak will form which of the heart components?
form outflow tract
In early heart formation, cells migrating through the posterior part of the primitive streak will form which of the heart components?
form the atria
hydatidform mole is related to which genetic-related condition?
paternal imprinting
formation of ribs on the lumbar and sacral vertebrae occurs as a result of what genetic condition?
knockout of all Hox 10 paralogues
Myoepithelial cells in the lactating breast contract in response to what hormone?
oxytocin
Which components of the hair and its follicle are derived from ectoderm?
- hair follicle -nails -hair shaft
- sebaceous glands -secretory and duct components of mammary gland
Which components of the hair and its follicle are derived from mesoderm?
arrector pilli
The proatlas anlage contributes to the formation of which structures?
fuses with 3 upper occipital sclerotomes to form the OCCIPITAL BONE
What factor is antagonistic to BMP and, when down regulated, allows sutures to fuse?
Noggin
what structure is/are derived from the trophoblast?
placenta and chorion
-forms outer layer of blastocyst
List/describe factors/conditions that facilitate the exchange of oxygen between the fetal and maternal blood.
Bohr effect— fetal blood can carry greater quantity of Oxygen than maternal blood for given blood P02–> delivers increased O2 to the tissues
Double Bohr effect—double shift in maternal blood and fetal blood
fetal blood hemoglobin concentration is about 50% greater than maternal
fetal hemoglobin has a higher affinity for O2
What factor is in the permanent cartilage pathway that causes chondroblasts to secrete collagen II and cartilage matrix and is continually expressed in permanent cartilage?
sox 9
What is/are the effects of HCG on the corpus luteum?
- prevents involution of corpus luteum (CL)
- causes CL to increase secretion of progesterone and estrogens
- causes increased growth in CL
What cells can be considered immigrant with regard to the development of integument?
- melanoblasts–from neural crest
- Langerhan’s cells–from bone marrow
- Merkel cells–from neural crest
Describe the characteristics of satellite cells in reference to muscle tissue differentiation
- able to fuse with muscle fiber and provide growth
- cannot form new muscle fibers
- fxn as stem cells
- give rise to myogenic precursor cells—replace damaged muscle by proliferating, fusing, and differentiating into skeletal muscle fibers
What signaling molecules are expressed by the isthmic organizer?
mostly FGF-8, Wnt-1, En-1, En-2
What germ layers make up each of the extraembryonic membranes?
amnion–inner cell mass: epiblast derivative
yolk sac-inner cell mass: hypoblast derivative
allantois-inner cell mass; interfaces with placenta via umbilical cord
chorion–part of fetal maternal interface
What germ layer is absent from the oropharyngeal membrane?
-lack of mesoderm–>result in perforation of these plates
List the characteristics of the early placenta and relate to the late placenta
Early–thick, low permeability, small SA, total diffusion conductance is minuscule
Late–thin, high permeability, large SA, large increase in placental diffusion
Name the factors that is/are involved in the formation of rhombomeres 3 and 5
Krox-20
Describe the 3 circulatory arcs and their components in the 4-week embryo
vitelline arc-vitelline vessels
allantoic arc—allantoic (umbilical) vessels
embryonic arc–dorsal aorta, aortic arches, anterior cardinal vein, common cardinal vein, posterior cardinal vein, atrium, ventricle, ventral aorta
What transcription factor suppresses the formation of anterior gut structures and promotes hindgut development?
Cdx-2
At what time during pregnancy does maximum secretion of HCG occur?
10th-12th week of pregnancy
What role does p63 play in the formation of the intermediate layer of the epidermis and what is its relation to miR-203?
p63 initiates 3-layered epidermis-forms )basal germinative layer) and superficial peridermal layer
miR-203—inactivates p63 which allows intermediate layer to form
What is fillagrin and what is it specifically associated with?
Fillagrin—> filament associated protein that binds to keratin fibers in epithelial cells
–it interconnects the stratum granulosum of intermediate layer of the epidermis
Compare permissive and instructive induction and give examples.
permissive induction—responding tissue has all the potentials that are to be expressed, and need only an environment that allows the expression of the traits
ex. fibronectin/laminin does not alter the type of cell that is to be produced, but only enables what has been determined to be expressed
instructive induction—-> signal from inducing cell necessary for initiating new gene expression in the responding cell- need for differentiating
ex. optic vesicle places under region of ectoderm causing region of ectoderm to from a lens
Which intramembranous bone in the body is the first to become ossified?
the clavicle
Prechordal (hypophyseal) cartilages contribute to the formation of which components of the embryonic skull?
basisphenoid bone
List characteristicss of early cardiac muscle cells
- does not express Myo D
- contract early
- maintains their ability to divide partially disassembling their contractile apparatus prior to cell division
Parachordal cartilages contribute to the formation of which components of the embryonic skull?
basioccipital portion of chondrocranium
What skull structures are derived from the membranous portion of the viscerocranium?
- part of the temporal -palatine
- zygomatic -vomer
- maxillary -pterygoid plates, mandible
- nasal - lacrimal
- tympanic ring
Name the four components of the typical embryonic pharyngeal arch
- skeletal element
- muscles
- branch of specific cranial nerve
- artery
