Embryology Flashcards by Erin O

At what stage of meiosis I are oocytes arrested until puberty?

a. Liplotene
b. Diplotene
c. Zygotene
d. None of the above

b. Diplotene

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At what stage of meiosis II are oocytes arrested until fertilization?

a. Liplotene
b. Diplotene
c. Zygotene
d. Metaphase
e. Pachytene

d. Metaphase

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Which hormone contributes to the proliferation phase of the menstrual cycle?

a. Estradiol
b. Estrogen
c. Progesterone
d. hCG

a. Estradiol; via granulosa cells of the ovarian follicle

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Which hormone contributes to the secretory phase of the menstrual cycle?

a. Estradiol
b. Estrogen
c. Progesterone
d. hCG

c. Progesterone; via granulose and thecal cells of ovarian follicle

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Which enzyme is one of the major enzymes in the acrosome during fertilization that breakdowns centers b/w the corona radiata cells?

a. Ligase
b. Hyaluronidase
c. Pepsin
d. Fibronectin
e. Acrosin

b. Hyaluronidase

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Which enzyme is most important in penetrating the zona pellucida during fertilization, allowing spermatozoa to travel through?

a. Ligase
b. Hyaluronidase
c. Pepsin
d. Fibronectin
e. Acrosin

e. Acrosin

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Which of the following transcription factors are examples of homeobox containing genes?

a. Hox and Shh
b. Shh and Pax
c. Pax and Hox
d. RA and Hox

c. Pax and Hox; sequence of highly conserved genes of 180 nts coding for 60 aa

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Which signaling molecule is important in the formation of axial structures of the notochord?

a. Hox
b. Pax
c. Shh
d. RA

c. Shh; induces overlying ectoderm to convert to neural ectoderm (TF = Foxa-2, Goosecoid; Signals = Noggin, Chordin)

Primary inductor in primary neural induction

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Which signaling molecule is the principal organizer of the isthmic organizer that organizes and polarizes midbrain and cerebellum?

a. Hox
b. Pax
c. FGF-8, Wnt-1
d. Shh

c. FGF-8, Wnt-1

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Three signaling centers of the neural tube (isthmic organizer, anterior neural ridge, zona limitans) contain many functions, which one organizes the telenchephalon, parts of diencephalon, olfactory area and the pituitary gland?

a. Isthmic organizer
b. Anterior neural ridge
c. Zona limitans
d. All of the above

b. Anterior neural ridge; Shh and FGF-8

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Which of the following signaling centers of the neural tube organizes the border between dorsal and ventral thalamus?

a. Isthmic organizer
b. Anterior neural ridge
c. Zona limitans
d. All of the above

c. Zona limitans; Shh

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Which XE tissue is made up of ectoderm and mesoderm tissue?

a. Amnion
b. Yolk sac
c. Chorion
d. Allantois
e. Amnion & Chorion
f. Yolk sac & Allantois

e. Amnion & Chorion

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Which XE tissue is made up of endoderm and mesodermal tissue?

a. Amnion
b. Yolk sac
c. Chorion
d. Allantois
e. Amnion & Chorion
f. Yolk sac & Allantois

f. Yolk sac & Allantois

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What tissue of the placenta directly interfaces with the maternal uterine connective tissue?

a. Anchoring villi
b. Cytotrophoblast
c. Syncytiotrophoblast
d. Chorion

b. Cytotrophoblast

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Which of the following developmental disturbances is due to defective fields?

a. Syndactyly
b. Pelvic kidneys
c. Cleft palate
d. Sirenomelia

d. Sirenomelia

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Which of the following developmental disturbances is due to failure of migration?

a. Syndactyly
b. Pelvic kidneys
c. Cleft palate
d. Sirenomelia

b. Pelvic kidneys

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Which of the following genes is involved in the development of the vertebral column?

a. Shh
b. Hox
c. Pax
d. FGF

b. Hox

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Which of the following is involved in the earliest stage of skeletal muscle tissue development?

a. Myogenic cells
b. Myoblasts
c. Myotubes
d. Muscle fibers

a. Myogenic cells; originate in somites, mitotic cells

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Which of the following are characterized by appearance of actin, myosin, troponin and tropomyosin and form sarcomeres?

a. Myogenic cells
b. Myoblasts
c. Myotubes
d. Muscle fibers

c. Myotubes

T/F; Satellite cells are located b/w sarcolemma and basal lamina and are only mitotic

False; mitotic AND myogenic

Do not form new muscle fibers

Which gene did Riddle suggest is a morphogen that was expressed by the posterior organizing region during asymmetry of vertebrate limb development of the 3 axes?

a. Hox
b. Shh
c. Pax
d. FGF

b. Shh; activated by RA

Treatment of RA in anterior part caused cells to behave like those in posterior region = creating symmetry

During establishment of the three axes of limb development, what happens when a limb disc is transplanted to the opposite side?

AP axis is reversed

DV axis is not reversed

Normal limb bud forms w/ AP axis reversed

During establishment of the three axes of limb development, what happens when a limb disc is rotated 180 degrees?

Both AP and DV axis are reversed

Or normal limb with AP axis reversed and no DV axis

Proliferation within the neural tube contains pseudostratified epithelium with a single layer of columnar cells, what is the result of daughter cells when the metaphase plate is perpendicular?

a. Cells become post-mitotic
b. Cells remain proliferative
c. Cells become a neuroblast
d. Cells travel to PNS

b. Cells remain proliferative

If parallel = close to lumen = proliferative, further from lumen = postmitotic (external limiting membrane)

During motor axon guidance, what happens if the forelimb rudiment of an amphibian embryo is cut out and transplanted to a position near the original one? a. Brachial nerves do not develop b. Brachial nerves develop from their original path c. Brachial nerves deviate from normal path and deflect in direction of the transplanted limb d. Brachial nerves develop but are non functional

c. Brachial nerves deviate from normal path and deflect in the direction of the transplanted limb Limb will be fully functional if distance of transplanted limb is not too great

Neural crest cells are able to differentiate into the following EXCEPT: a. Melanocytes b. Schwann cells c. Cartilage and skeletal elements d. Chromaffin cells

Cartilage and skeletal elements

During neural crest cell differentiation exposed rat neural crest cells in vitro transferred to glial growth factor suppress the ability of cells to form neurons and form Schwann cells instead

Lens placode develops into what major eye structure? a. Choroid, Sclera b. Pigmented and neural retina c. Optic vesicle d. Cornea

d. Cornea Lens placode --> Lens vesicle --> Lens and Cornea

Which molecule is important in the induction of optic vesicle to lens placode? a. Pax6 b. FGF4 c. Hox d. Shh

Pax-6

Which of the following does the neural crest form during eye development? a. Choroid, Sclera b. Pigmented retina c. Neural retina d. Lens e. Cornea

a. Choroid, Sclera

Which of the following is NOT a derivative of the metanephric diverticulum/ureteric bud? a. Adult ureter b. Renal pelvis c. Bladder d. Collecting tubules

c. Bladder Ureteric bud via mesonephric ducts

Which of the following does the metanephrogenic blastemata develop into? a. Renal tubules b. Adult ureter c. Renal pelvis d. Bladder

a. Renal tubules Requires mesonephric duct

During male development, testosterone produced by which structure causes the retention of the mesonephric ducts when SRY is present? a. Sertoli cells b. Cells of Leydig c. Epidydimis d. Interstitial cells of rete cords e. Prostate gland

d. Interstitial cells of the rete cords When SRY available, Sertoli cells in sex cords secrete Mullerian inhibitory factor Female = mesonephric cells regress

Which pair of aortic arch forms the internal carotids? a. First b. Second c. Third d. Fourth e. Fifth f. Sixth

c. Third External carotids = cranial extensions of paired ventral aortae cranial to 3rd arches

Which pair of aortic arches eventually degenerate? a. First, Second, & Fifth b. Third, Fourth & Fifth c. Fifth and Sixth d. First and Third

a. First and Second

Where are the common carotids derived from? a. Dorsal aortae cranial to 3rd arch b. Ventral aortae cranial to 3rd and 4th arches c. First arch d. First and Second arch

b. Ventral aortae cranial to 3rd arches External carotids = cranial extensions of paired ventral aortae cranial to 3rd arches

Where is the right subclavian artery derived from? a. Left fourth aortic arch b. Right fourth aortic arch c. Left fifth aortic arch d. Right fifth aortic arch

b. Right fourth aortic arch

What is the derivative of the aortic arch? a. Left fourth aortic arch b. Right fourth aortic arch c. Left fifth aortic arch d. Right fifth aortic arch

a. Left fourth aortic arch

What is the fate of the sixth pair of aortic arches? a. Systemic system b. Pulmonary system c. Left subclavian artery d. Right subclavian artery

b. Pulmonary system

What are derivatives of the primary heart field? a. Left ventricle and atria b. Right ventricle and atria c. Left and right ventricle d. Right ventricle and outflow tract e. Ventricles and atria

a. Left ventricle and atria High [RA] = atrial identity No [RA] = ventricular identity Primary heart field = Hand-1

Which of the following do cells of the primary heart field express? a. Hox b. Shh c. Hand-1 d. Hand-2

c. Hand-1

What are the derivatives of the secondary heart field? a. Left ventricle and atria b. Right ventricle and atria c. Left and right ventricle d. Right ventricle and outflow tract e. Ventricles and atria

d. Right ventricle and outflow tract Hand-2

Which of the following separates the atrium into left and right chambers? a. Interatrial septum primum b. Interatrial septum secundum c. Interatrial foramen primum d. Interatrial foramen secundum e. Foramen ovale

a. Interatrial septum primum Downward growth from atrium to endocardial cushion

Which of the following forms the right to left atrial shunt? a. Interatrial septum primum b. Interatrial septum secundum c. Interatrial foramen primum d. Interatrial foramen secundum e. Foramen ovale

c. Interatrial foramen primum Space b/w the leading edge of the septum primum and endocardial cushion

Which of the following forms the right to left atrial shunt? a. Interatrial septum primum b. Interatrial septum secundum c. Interatrial foramen primum d. Interatrial foramen secundum e. Foramen ovale

e. Foramen ovale Space formed within the septum secundum