Nervous System

Question 1

When does human brain development begin?

Answer 1

In the 3rd week post conception

Question 2

When is the embryonic period?

Answer 2

Conception to week 9

Question 3

The 2 layers of the embryo

Answer 3

Epiblast and hypoblast

Question 4

What determines the migration of cells through primitive streak and then rostral-caudal migration?

Answer 4

Nodal signalling

Question 5

Which layer are skin, nails, hair and neural tissue from?

Answer 5

Ectoderm tissue

Question 6

Which layer are muscle, bone and the vascular system from?

Answer 6

Mesoderm

Question 7

Which layer are the gut and respiratory system from?

Answer 7

Endoderm

Question 8

Which is the first well defined neural structure to form?

Answer 8

The neural tube

Question 9

When does the neural tube form?

Answer 9

Days 20-27

Question 10

Which cells form the neural plate

Answer 10

Neural progenitor cells

Question 11

What is the ventricular zone?

Answer 11

the inside of the neural tubes lined with neural progenitors

Question 12

What does the anterior/rostral tube become?

Answer 12

The anterior/rostral tube becomes the brain

Question 13

What does the hollow centre of the neural tube become?

Answer 13

The hollow centre of the tube will become the ventricular system and central channel of the spinal cord

Question 14

What does the caudal tube become?

Answer 14

The caudal tube will become the spinal cord

Question 15

What does neural patterning in the embryonic period set the stage for?

Answer 15

Neural patterning in the embryonic period sets the stage for the latter development

Question 16

Where is the highest concentration of Emx2 found?

Answer 16

More Emx2 found in the posterior/caudal

Question 17

Where is higher concentration of Pax6 found?

Answer 17

Higher concentration of Pax6 at anterior/rostral

Question 18

Emx2 and Pax6 signalling

Answer 18

High conc. Pax6 with low conc. of Emx2 induce progenitor to differentiate into motor neurons
Low conc. Pax6 and high conc. Emx2 induce visual cortical neurons

Question 19

Where do progenitor cells stay and where to neurone migrate to?

Answer 19

Progenitor cells stay in the ventricular zone and continue to divide and produce more cells.
Neurons migrate to the developing neocortex

Question 20

Neuronal migration

Answer 20

Somal translocation
Radial glial guides
Tangential migration and signalling pathways

Question 21

Dendrites and arbors

Answer 21

Multiple dendrites form ‘arbors’ around the neuron

Question 22

Which cells develop processes which wrap around axons to form myelin sheaths?

Answer 22

Oligodendrocyte progenitor cells develop processes which wrap around axons to form progenitor cells

Question 23

Myelination occurs in what order? i.e. bottom to top etc

Answer 23

Bottom to top from back to front

Question 24

When does myelination mostly occur?

Answer 24

Myelination is mainly in the first two years of life but ongoing into the twenties

Question 25

Anencephaly

Answer 25

Anterior neural tube not closed

Question 26

Spina bifida

Answer 26

Posterior neural tube not closed

Question 27

Why are the gyri and sulci needed?

Answer 27

To accomodate the proliferating neurons

Question 28

Post-natal brain development

Answer 28

Post-natal proliferation | Myelination

Question 29

Holoprosencephaly

Answer 29

Failure of forebrain to develop normally

Question 30

What does PLP-1 gene encode?

Answer 30

PLP-1 encodes the main protein in myelin | transmembrane proteolipid protein

Question 31

On which chromosome is PLP-1 gene located?

Answer 31

Chromsome X

Question 32

What causes Pelizaeus merzbacher disease?

Answer 32

Mutations in the PLP-1 gene

Question 33

Mutations in the PLP-1 gene could cause what?

Answer 33

Pelizaeus merzbacher disease | Spastic paraparesis 2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span.

Question 34

Mutations in the PLP-1 gene

Answer 34

Mutations in the PLP1 gene cause a spectrum of disorders Pelizaeus –Merzbacher the most severe Presents in infancy or early childhood with nystagmus, hypotonia, and cognitive impairment Progresses to severe spasticity and ataxia. Life span is shortened. Spastic paraparesis 2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span.

Question 35

Pelizaeus merzbacher disease

Answer 35

Mutations in the PLP1 gene cause a spectrum of disorders Pelizaeus –Merzbacher the most severe Presents in infancy or early childhood with nystagmus, hypotonia, and cognitive impairment Progresses to severe spasticity and ataxia. Life span is shortened. Spastic paraparesis 2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span.

Question 36

Spastic parapesis

Answer 36

Spastic paraparesis 2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span.

Question 37

CSF has the same composition as what?

Answer 37

Brain extracellular fluid

Question 38

What does a turbid or cloudy CSF indicate?

Answer 38

may indicate inflammatory cells, the presence of micro-organisms or raised protein

Question 39

How much glucose should be in CSF (compare to blood glucose)

Answer 39

CSF should have at least 2/3rds of the glucose in blood. A ratio of CSF to blood glucose less than 0.5 is considered pathological

Question 40

What does raised protein in CSF suggest?

Answer 40

Inflammation/infection

Question 41

What is most commonly measured in CSF?

Answer 41

Protein and glucose

Question 42

What do oligoprotein bands indicate?

Answer 42

Oligoprotein bands indicate inflammation in the CNS

Question 43

Normal CSF fluid

Answer 43

Normal CSF should have no RBC cells, <5 WBC/ml and a CSF protein of less than 2g/dl

Question 44

What is the purpose of a lumbar puncture

Answer 44

Sampling the CSF | Measuring the CSF pressure

Question 45

Finding position to carry out lumbar puncture

Answer 45

Palpate the iliac crests laterally.  The line connecting the iliac crests should correspond to approximately the L4 spinous process, one to two interspaces above the optimal space to access the subarachnoid space.

Question 46

Which position does the spinal cord usually end

Answer 46

L1

Question 47

Which structure anchors the spinal cord and dural sac distally?

Answer 47

The filum terminale

Question 48

The filum terminale?

Answer 48

Anchors the spinal cord and dural sac distally

Question 49

Indications for lumbar puncture

Answer 49

1. Suspected CNS infection 2.  Suspected subarachnoid hemorrhage 3.  Therapeutic reduction of cerebrospinal fluid (CSF) pressure 4. Sampling of CSF for any other reason

Question 50

Contraindictions for lumbar puncture

Answer 50

1. Local skin infections over proposed puncture site 2. Raised intracranial pressure (ICP) 3. Suspected spinal cord mass or intracranial mass lesion (based on lateralizing neurological findings or papilledema) 4. Uncontrolled bleeding diathesis 5. Spinal column deformities (may require fluoroscopic assistance) 6. Lack of patient cooperation (anaesthetic may be required in children)