Test 1 - Congenital Disorders and NMJ Topics

Question 1

The neural tube develops on the surface of the embryo at 14 days of gestation and closes between ___ and ___ days

Answer 1

18 and 26

Question 2

The primitive cerebral hemispheres have formed by the ___ week

Answer 2

7th

Question 3

Most major neuronal groups have formed by the end of ___ weeks.
At this point the cerebral hemispheres are smooth with only the lateral and calcarine fissure
starting to form.

Answer 3

20

Question 4

___ is a failure of the rostral neuropore to close.
The forebrain neuroectoderm fails to separate from the cutaneous ectoderm, and a red area cerebrovasculosa is seen where the calvarium (skullcap) would have developed

Answer 4

Anencephaly

Question 5

Anencephaly is a failure of the rostral neuropore to close.
The forebrain neuroectoderm fails to separate from the cutaneous ectoderm, and a ___ is seen where the ___ would have developed

Answer 5

red area cerebrovasculosa; calvarium (skullcap)

Question 6

___ is a defect in the skull due to failure in closure of the neural tube, with protrusion of leptomeninges ± brain.
Distinguished from anencephaly because they have an epidermal covering over the cranial neural tube closure defects

Answer 6

Encephalocele, aka cranium bifidum

Question 7

Encephalocele/cranium bifidum is distinguished from anencephaly because they have ___

Answer 7

an epidermal covering over the cranial neural tube closure defects

Question 8

Most myelomeningoceles occur in the ___ area because it is the last part of the neural tube to close

Answer 8

lumbar

Question 9

___ occur due to failure of posterior neuropore closure, and consist of a neural placode without epidermal covering, with CSF leak

Answer 9

Myelomeningocele

Question 10

Neural tube defects arise from failure of the ___ to form a complete, closed tube during primary neurulation, or from disordered differentiation of the caudal cell mass into the ___ and ___ during secondary neurulation

Answer 10

neurectoderm; conus medullaris and filum terminale

Question 11

Neural tube defects arise from failure of the neurectoderm to form a complete, closed tube during ___ neurulation, or from disordered differentiation of the ___ into the conus medullaris and filum terminale during ___ neurulation

Answer 11

primary; caudal cell mass; secondary

Question 12

___ is a skin-covered, CSF-filled mass that is continuous with the CSF in the spinal canal

Answer 12

Meningocele

Question 13

A ___ reflects a premature separation of the cutaneous ectoderm during the process of neurulation that allows mesenchyme to enter the unclosed neural tube and differentiate into fat.

Answer 13

lipomyelocele/lipomyelomeningocele

Question 14

___ is a failure of the posterior neuropore to close but is often asymptomatic and requires no treatment

Answer 14

Bony spina bifida occulta

Question 15

A dermal dimple, a hairy patch of skin, a lipoma or other midline visible mass, a dermal sinus, or capillary hemangioma in the ___ region is suggestive of a ___

Answer 15

lumbosacral; underlying spinal dysraphism

Question 16

In the typical newborn, the conus medullaris is found at the level of the ___ vertebral body.

Answer 16

L3

Question 17

When the infant reaches three months of age, the conus should not be below the lower margin of the ___ vertebral body.

Answer 17

L2

Question 18

In the adult, the conus typically lies at the level of the ___ vertebral bodies.

Answer 18

L1-L2

Question 19

Neural tube defects in the lumbar region can have the effect of ___

Answer 19

tethering the spinal cord - prevents the conus medullaris from rising

Question 20

Lumbar neural tube defects result in tethering of the spinal cord, preventing the conus medullaris from rising, and will present with ___

Answer 20

pain, upper motor neuron signs (hyperreflexia, spasticity), and urinary incontinence (these fibers are often affected)

Question 21

A ___ is the finding of cerebellar tonsils that are elongated and pushed down through the foramen magnum, blocking the normal flow of cerebrospinal fluid.

Answer 21

Chiari Type I malformation

Question 22

A Chiari Type I malformation is the finding of ___ that are elongated and pushed down through the foramen magnum, blocking the normal flow of cerebrospinal fluid.

Answer 22

cerebellar tonsils

Question 23

A Chiari Type I malformation is the finding of cerebellar tonsils that are elongated and pushed down through the foramen magnum, blocking the ___

Answer 23

normal flow of cerebrospinal fluid from the central canal to the subarachnoid space

Question 24

The blockage of normal CSF flow from the central canal to the subarachnoid space in a Chiari Type I malformation can cause ___ or syringomyelia- formation of a CSF-filled cyst that breaks out of the central canal and dissects into the substance of the cord

Answer 24

hydromyelia - accumulation of CSF in the central canal

it either accumulates in the canal or it bursts out of it

Question 25

The blockage of normal CSF flow from the central canal to the subarachnoid space in a Chiari Type I malformation can cause hydromyelia - accumulation of CSF in the central canal, or ___

Answer 25

syringomyelia - formation of a CSF-filled cyst that breaks out of the central canal and dissects into the substance of the cord

it either accumulates in the canal or it bursts out of it

Question 26

Type I Chiari malformations are not associated with ___, while Type II Chiari malformations always are, particularly at the thoraco-lumbar level

Answer 26

myelomeningocele

failure of posterior neuropore closure, and consist of a neural placode without epidermal covering, with CSF leak

Question 27

Type ___ Chiari malformations are ALWAYS associated with thoraco-lumbar level myelomeningoceles

Answer 27

II

failure of posterior neuropore closure, and consist of a neural placode without epidermal covering, with CSF leak

Question 28

Type II Chiari malformations are associated with elongation of the ___ (NOT the cerebellar tonsils), which are pushed down through foramen magnum and can also block CSF flow

Answer 28

cerebellar vermis

Question 29

Type II Chiari malformations are associated with abnormalities of the brainstem, including “___” of the midbrain tectal plate, and a “___” in the medulla

Answer 29

brainstem; beaking; z-kink

Question 30

Type II Chiari malformations are associated with abnormalities of the ___ including a low-lying ___ and osseous abnormalities of the skull

Answer 30

dural venous sinus; confluence of sinuses (torcula herophili)

Question 31

Type II Chiari malformations are associated with ___ abnormalities of the skull

Answer 31

osseous

Question 32

Type II Chiari malformations arise because of ___

Answer 32

failure of neural folds to close, leaving a dorsal defect or myeloschisis, and subsequent CSF leakage through the central canal and into the amniotic fluid and creating a collapse of the primitive ventricular system

Question 33

Holoprosencephaly is when the the prosencephalon fails to ___ in the fifth week of life

Answer 33

cleave into the two lateral ventricles and one third ventricle

Question 34

\_\_\_ holoprosencephaly (arhinencephaly) is the type in which there is no evidence of division of cerebral
cortex whatsoever

Answer 34

Alobar

It is the most severe type

Question 35

___ holoprosencephaly has partial cleavage with the cerebral hemispheres fused at the frontal region only, and the brain has a horseshoe appearance single central ventricle

Answer 35

Semilobar

Question 36

___ holoprosencephaly is where the cerebral hemispheres are separated anteriorly and posteriorly with some degree of fusion of structures

Answer 36

Lobar

It is the least severe

Question 37

___ development is linked to the differentiation of the forebrain and therefore deformities are frequently present in cases of holoprosencephaly

Answer 37

Facial and ocular

Question 38

Facial and ocular development is linked to the differentiation of the ___ and therefore deformities are frequently present in cases of ___

Answer 38

forebrain; holoprosencephaly

Question 39

Prosencephalic development depends on morphogen gradients leading to regional gene expression. Notably, sonic hedgehog is secreted from ventral sites giving rise to a concentration gradient that is lower ___

Answer 39

dorsally

Question 40

Sonic hedgehog, a morphogen, is secreted from ventral sites giving rise to a concentration gradient that is lower dorsally and its absence is implicated in ___

Answer 40

holoprosencephaly

Question 41

The most common cerebellar hypoplasia is ___, which has partial or complete absence of formation of the cerebellar vermis, cystic dilatation of the fourth ventricle, and upward displacement of the tentorium

Answer 41

Dandy-Walker syndrome, which is often sporadic

Question 42

T/F: Dandy Walker syndrome is associated with neural tube defects but cannot be prevented with folic acid supplementation

Answer 42

F, it is not associated with neural tube defects and can’t be prevented, but it IS often associated with other cerebral and/or visceral anomalies

Question 43

Vascular-ischemic destructive events in the ___ trimester of pregnancy are usually to blame for large destructive events in the fetal brain

Answer 43

late second or early third

Question 44

Ischemic events are large in the fetal brain because of the relative paucity of ___

Answer 44

glial reaction to injury

Question 45

___ had previously been a cause of significant number of strokes in the perinatal period because of difficult delivery of the full-term infant

Answer 45

Birth trauma

Question 46

Infantile infarcts are often in the ___ between the anterior, middle, and posterior cerebral arteries because of hypoperfusion.

Answer 46

watershed zones, where two arteries barely meet

Question 47

Full-term infant strokes will often result in ___, while adult strokes are incapable of anything like this

Answer 47

mushroom-shaped gyri – a condition known as ulegyria, because the viable cortex at the less-injured crest of the
gyri would continue to develop, while the more severely infarcted cortex at the depths of sulci could not

Question 48

The ___ is next to the lateral ventricles, the deep part of the brain, from which neurons and glia migrate outwards, and is thus prone to hemorrhage in pre-term infants

Answer 48

germinal matrix

Question 49

When preterm infants less than 32-34 weeks gestation develop vascular complications in the brain they get hemorrhage into the ___, the most common cause of cerebral palsy

Answer 49

germinal matrix

Question 50

Treatment of preterm/low birth-weight (

Answer 50

vitamin E

Question 51

The primitive streak regresses to form the caudal eminence/end bud which forms the ___ and ___

Answer 51

conus medullaris and filum terminale

Question 52

The primitive streak regresses into an insignificant structure in the sacrococcygeal area, but may form a ___

Answer 52

sacrococcygeal teratoma

Question 53

Neural tube defects can be prevented by mom taking ___

Answer 53

0.4 mg folic acid per day

Question 54

Holoprosencephaly is associated with mutations in the ___ gene

Answer 54

SHH

Question 55

___ is characterized by abnormal clefts lined with grey matter that extend from the ependyma of the cerebral lateral ventricles to the pia mater

Answer 55

Schizencephaly

Question 56

Most childhood strokes (55%) are ischemic, though the ___ (45%) are the ones with identifiable causes

Answer 56

hemorrhagic

Question 57

Chiari Type II defects are defects in the ___; Chiari Type I are not

Answer 57

neural tube

Question 58

Trisomy 13 is linked to ___

Answer 58

holoprosencephaly

Question 59

Trisomy 21 has an increased risk of ___

Answer 59

Alzheimer’s