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Flashcards in EXAM III Final Deck (106)
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1

Weaver and reeler mutations are involved in the layering of the brain cortex (6 layers of gray matter). It has been shown that a weaver mutant causes behavioral defects related to abnormal cerebellum function. What is the morphological basis for the weaver mutant?

a. Absence of normal cortical layering
b. Abnormal migration of radial glial cells that normally form granular layer or cerebellar cortex
c. Abnormal migration of astrocytes that normally form granular layer or cerebellar cortex
d. Abnormal migration of radial glial cells that normally form cortical layer of cerebellar cortex

Abnormal migration of RADIAL GLIAL CELLS that normally make up the GRANULAR LAYER

2

Weaver and reeler mutations are involved in the layering of the brain cortex (6 layers of gray matter). It has been shown that a reeler mutant causes behavioral defects related to abnormal cerebellum function. What is the morphological basis for the reeler mutant?

a. Absence of normal cortical layering
b. Abnormal migration of radial glial cells that normally form granular layer or cerebellar cortex
c. Abnormal migration of astrocytes that normally form granular layer or cerebellar cortex
d. Abnormal migration of radial glial cells that normally form cortical layer of cerebellar cortex

Absence of normal cortical layering

3

What is the relation of reelin to reeler during the development of the brain cortex?

It has been shown that an extracellular protein Reelin is defective in the reeler mutant

Reelin = stop signal for radial neuronal migration or insertional signal for migrating neurons

4

Define Rachischisis; what is it associated with?

Closure defect of the spinal cord

Chronic infection, motor and sensory defects and disturbances in bladder function

5

What is the primary defect in spina bifida occulta, meningocele and myelomeningocele? Characteristics of each?

Defect in the formation of bony covering over the spinal cord

Bifida occulta = spinal cord and meninges in place, incomplete neural arch covering (tuft of hair)

Meningocele = missing dura mater, arachnoid space bulges out

Myelomeningocele = spinal cord bulges or entirely displaced into the protruding subarachnoid space

6

Which of the following are the major derivatives of the diencephalon?

a. Epithalamus, Thalamus and pons
b. Epithalamus, Hypothalamus and pons
c. Epithalamus, Thalamus and Hypothalamus
d. Cerebellum, Thalamus and pons

C. Epithalamus, thalamus and hypothalamus

7

The forebrain contains three patterning centers, which signal is used for the rostral patterning center? (rostral, dorsal, ventral)

a. Shh
b. Hox
c. Shh
d. BMPs and Wnts
e. FGF-8

E. FGF-8

8

The forebrain contains three patterning centers, which signal is used for the dorsal patterning center?

a. Shh
b. Hox
c. Shh
d. BMPs and Wnts
e. FGF-8

D. BMPs and Wnts

9

The forebrain contains three patterning centers, which signal is used for the ventral patterning center?

a. Shh
b. Hox
c. Shh
d. BMPs and Wnts
e. FGF-8

A. Shh

10

The topographical arrangement of the myelencephalon is almost identical to the spinal cord. What is the major topographical change?

Pronounced expansion of the roof plate to form the thin roof over the fourth ventricle

11

Expression of which set of genes seems to be responsible for the differentiation of specific nuclei in the myelencephalon?

a. Shh
b. Hox
c. Shh
d. BMPs and Wnts
e. FGF-8

Hox genes

12

Epithelial-mesenchymal transformations.
While in the neural tube, neural crest cells are epithelial. Which of the following factors are involved in breaking free of the neural tube?

a. BMPs and Wnts
b. Snail-1, Snail-2, and Foxd3
c. Gbx-2, Msx-1,2, and Pax-3,7
d. FGF-8 and Wnts
e. All of the above

Snail-1, Snail-2, Wnts

13

Neural crest cells undergo 3 migratory pathways; ventral, ventralateral, and dorsolateral. The pathways result in formation of many components of the NS. Which of the following do neural crest cells NOT form?

a. Melanocytes
b. Spinal ganglia and Schwann cells
c. Motor neurons
d. Adrenal chromaffin cells
e. Sympathetic ganglion

Motor neurons

Sympathetic ganglion and adrenal chromaffin cells (ventral)
Spinal ganglia and Schwann cells (ventralateral)
Melanocytes (dorsolateral)

14

Neural crest cells are not always irreversibly fixed along a single pathway. If neural crest cells from the trunk/thoracic are transplanted into the head, what normal derivatives are not formed?

a. Cartilage or skeletal elements
b. Adrenergic Sympathetic neurons
c. Cholinergic parasympathetic neurons
d. Melanocytes

Cartilage or skeletal elements

15

Which rhombomeres do the neural crest cells arise from that make up the vagal crest?
Innervation for what organ?
Where does it arise from and exit?

R4-7

Make up vagal crest and form parasympathetic innervation for digestive tract

Arise from the circumpharyngeal crest and exit S1-7

16

Which somites does the circumpharyngeal neural crest arise from?
Which PA do they pass behind?
Which CN do they provide a pathway for?

S1-7

Pharyngeal arch 6

Cells migrate ventrally and then cranially to provide pathway for CN XII and related musculature

17

Which factor maintains the competence of neural cells to differentiate into autonomic neurons?

a. Slit-2
b. Mash-1
c. Noggin
d. Chordin
e. Shh

Mash-1

18

Which of the following is caused by Pax-3 mutations, involves various combinations of pigmentation defects (commonly a white stripe in the hair and other pigment anomalies in the skin), deafness, cleft palate, and ocular hypertelorism?

a. Waardenburg's syndrome
b. CHARGE
c. DiGeorge syndrome
d. Neurofibromas
e. Hirschsprung's disease

Waardenburg's syndrome - white forelock/stripe in hair

19

Which of the following includes defects of the trunk and cranial neural crest which involves coloboma, heart disease, atresia of nasal choanae, retardation of development, genital hypoplasia in males, and anomalies of the ear?

a. Waardenburg's syndrome
b. CHARGE
c. DiGeorge syndrome
d. Neurofibromas/Von Recklinghausen's disease
e. Hirschsprung's disease

CHARGE - coloboma

20

Which of the following is associated with a deletion on chromosome 22 that encompasses up to 15 genes, characterized by hypoplasia and reduced function of the thymus, thyroid, and parathyroid glands and cardiovascular defects, including persistent truncus arteriosus and abnormalities of the aortic arches?

a. Waardenburg's syndrome
b. CHARGE
c. DiGeorge syndrome
d. Neurofibromas/Von Recklinghausen's disease
e. Hirschsprung's disease

DiGeorge syndrome

21

Which of the following is a common genetic disease manifested by multiple tumors of neural crest origin, with characteristics of cafe au lait spots (light brown pigmented lesions) on the skin, multiple peripheral nerve tumors, and occasional gigantism of a limb/digit?

a. Waardenburg's syndrome
b. CHARGE
c. DiGeorge syndrome
d. Neurofibromas/Von Recklinghausen's disease
e. Hirschsprung's disease

Neurofibromas/Von Recklinghausen's disease - peripheral nerve tumors

22

The preplacodal region encircles the cranial plate and is often induced by cranial mesoderm and neural tube, which of the following pathways are activated during this induction?

a. FGF activation and Wnt and BMP inhbition
b. Wnt activation and FGF and BMP inhibition
c. BMP activation and FGF and Wnt inhibition
d. FGF and Wnt activation and BMP inhibition
e. FGF and BMP activation and Wnt inhibition

FGF activation and Wnt and BMP inhibition

23

BMP concentration is a major factor in the induction in placodes. What forms in the area with the greatest BMP concentration?

a. Placodes
b. Neural crest
c. Neural plate
d. Neural folds
e. Neural tube

Neural plate

24

BMP concentration is a major factor in the induction in placodes. What forms in the area with the least BMP concentration?

a. Placodes
b. Neural crest
c. Neural plate
d. Neural folds
e. Neural tube

Placodes

25

BMP concentration is a major factor in the induction in placodes. What forms in the area with the middle BMP concentration?

a. Placodes
b. Neural crest
c. Neural plate
d. Neural folds
e. Neural tube

Neural crest

26

Describe the formation of the optic stalk and what structures are continuous with what

Optic stalk
Optic vesicle
Choroid fissure
Hyaloid artery

Optic stalk = lateral evagination of diencephalon that enlarges distally to form optic vesicle

Optic vesicle asymmetrically invaginates w/ groove alongside

Groove = choroid fissure that's continuous with optic stalk groove

Optic stalk groove is continuous with posterior chamber of eye

Hyaloid artery uses choroid fissure and optic stalk to pass into posterior chamber of eye

27

What events occur in the development of the eye when Pax6 is not expressed?

Only early optic vesicle formation occurs, no eye formation

Optic vesicle is not able to induce the formation of the lens placode from the lens ectoderm

Prospective lens ectoderm doesn't respond to optic vesicle induction

28

Which of the following is important during the formation of the lens when the lens separate from the lens vesicle from surface ectoderm causing posterior cells to transform into lens fibers?

a. FGF, BMP
b. Pax6
c. Foxe3
d. Wnt

Foxe3

29

Which of the following induces the optic vesicle to induce the lens ectoderm to form the lens placode by way of FGF and BMP?

a. Pax6
b. Foxe3
c. Wnt
d. All of the above

Pax6 - downregulation by neural crest cells prevents formation of prospective lens in surrounding areas

30

Which of the following is necessary for corneal induction?

a. Pax6
b. Foxe3
c. Wnt
d. FGF
e. BMP

Pax6