Nervous System I

Question 1

What does the neural tube become?

Answer 1

Brain and spinal cord (CNS)

Question 2

What does the neural crest become?

Answer 2

PNS + Meninges

Question 3

What are CNS and PNS separated by?

Answer 3

Pia layer of meninges

Question 4

Describe each part of the nervous system with respect to post-mitotic neurons, glia,
BBB, axonal basal lamina, and invading cells.

Answer 4

Both PNS and CNS have post-mitotic neurons. 4 types of glia and CNS, and Schwann
cells and satellite cells in PNS. BBB in CNS, Weak BBB in PNS. No axonal basal lamina in
CNS, yes axonal basal lamina in PNS. Invading cells (blood vessels, immune cells) in both.

Question 5

Which neurons are multipolar?

Answer 5

Motor, pre/post ganglionic

Question 6

Which neurons are pseudounipolar?

Answer 6

Sensory

Question 7

What does the soma contain of multipolar neurons?

Answer 7

Soma contains RER (Nissl body): proteins for whole cell. Tx distal axon: Kinesin. Slow
gel-sol anterograde. Fast retrograde: Dynein

Question 8

What helps increase speed of signal travelling down axon?

Answer 8

Increase diameter, salutatory conduction: glia wrap around axon (myelination at
internodes), ion channels patched at nodes; signal jumps from node to node

Question 9

Where is the cell body for a sensory unipolar cell?

Answer 9

Dorsal root ganglion

Question 10

Where is the cell body for a motor neuron?

Answer 10

Gray matter of brain/ventral horn of spinal cord

Question 11

What are the three coverings of the brain? What’s the function?

Answer 11

The meninges: Dura mater (periosteal and meningeal layers), arachnoid, pia mater.
Brain + spinal cord protection

Question 12

What are the three layers of cell bodies in the cerebellum?

Answer 12

Molecular layer (most superficial – contains mainly dendires and axons from cells in deeper layers). Purkinje cell layer – monolayer, contains Purkinje cells, which have huge
cell bodies and send axons out of cerebral cortex. Granular layer – packed with tiny cell
bodies of tiny neurons (granule cells)

Question 13

What’s gray matter made of? White matter? How do you distinguish them
histologically

Answer 13

Gray – neuronal somas and glia. White matter – neuronal axons and glia. Both also
contain endothelium and immune cells. Because white matter has vacuoles from
myelination

Question 14

What’s the intermediate filament for neurons?

Answer 14

Neurofilament

Question 15

Where will neurofilament show for motor neurons? Sensory?

Answer 15

Motor: gray matter & ventral horn. Sensory: dorsal root ganglion

Question 16

What are the two places satellite cells can be?

Answer 16

Dorsal root ganglion cell bodies, or autonomic post-ganglionic cell bodies

Question 17

How does the autonomic pathway work?

Answer 17

Synapse at autonomic ganglion and post-ganglionic to target organ (bladder/pancreas)

Question 18

What are supporting cells of the NS?

Answer 18

Glia, endothelium, immune cells

Question 19

_____ in the CNS are mitotic.

Answer 19

Glia

Question 20

What are the GFAP glial cells in the CNS and list brief functions?

Answer 20

Oligodendrocytes (provide myelin, one oligo insulates many neurons, NO basal lamina,
poor guidance for regeneration), Astrocytes (structure, repair, BBB, inhibit regen, NT
uptake, gap junctions), ependymal cells (CSF circulation, no basal lamina)

Question 21

What are the crucial components of the BBB?

Answer 21

Endothelium of blood vessel and astrocytes

Question 22

List the Non GFAP glia in the CNS

Answer 22

Microglia (monocyte –> vimentin –> immune), endothelium (vimentin), perivascular
macrophage (vimentin)

Question 23

If a glial cell nucleus is spotted in the CNS, what cell could it belong to?

Answer 23

oligodendrocyte, astrocyte, microglia, endothelium, macrophage. NOT ependymal cell, which is near the ventricles in the brain.