Neurocytology --review from M1

Question 1

PNS (compsition)

Answer 1

cranial nerves and spinal nerves

groups of neurons cluster in ganglion

Question 2

CNS (composition)

Answer 2

Brain and spinal cord

groups of neurons cluster into nuclei or form sheets of nuclei ( cortices)

Question 3

Who are the glial cells in the PNS

Answer 3

satellite cells and schwann cells

Question 4

who are the glial cells in the CNS

Answer 4

oligodendrocytes, astrocytes, ependymal cells, and microglia

Question 5

What layer of cells (embryo) does the neural tube form from?

Answer 5

Ectoderm

Question 6

Where (layer in embryo) do the neural crest cells come from?

Answer 6

Ectoderm

Question 7

Neural crest cells can derive into what types of structures/ cells?

Answer 7

Peripheral Neurons
Schwann cells
Satellite Cells
Adrenal Medulla (Chromaffin cells)
Meningeal coats-- pia mater and arachnoid
Melanocytes
Facial cartilage

Question 8

What does the Neural tube develop into?

Answer 8

Brain and spinal cord

Question 9

What cells compose neural tube? What do these cells give rise to?

Answer 9

epithelium with cilia

Neurons and glia of the CNS

Question 10

Function of Glia cells of CNS?

Answer 10

provide guidance (via production of a substrate) to migrating neurons and growth factor support

Question 11

Multipolar cells

Answer 11

many branches off of soma.

found in large motor neurons

Part of autonomic nervous system and integrated neurons (lie within brain and spinal cord)

Question 12

Pseudounipolar neuron

Answer 12

sensory neurons

Two parts that extend from cell body have joined. They have bypassed the cell body

Question 13

Dendritic spines

Answer 13

on dendrites

respond to excitatory or inhibitory input.
Very plastic system
- when they don’t have excitatory input they
pull back into dendrite.

Question 14

What does the dendritic membrane do?

Answer 14

it sums excitatory and inhibitory information that reaches the neuron.

Question 15

Histology: axon hillock

Answer 15

are in cell body that has no rER or golgi because that is where axon is coming off of.

stains a pale pink

Question 16

Histology: Nissle bodies

Answer 16

stacks of rER, free ribosomes and organelles (Golgi) in cell body of neuron that produce proteins to help support axon.

Question 17

chemical synapse

Answer 17

presynaptic (cluster of synaptic vesicles) and postsynaptic element (receptors)

Neuromuscular junction= Ach neurotransmitter

Question 18

What are the two proteins in charge of helping a pre-synaptic vesicle dock on the pre-synaptic membrane of a synapse?

Answer 18

VAMP and t-SNAREs

- calcium sensing proteins

Question 19

Where in the synaptic release process does congenital myasthenia syndrome affect?

Answer 19

impaired vesicle recycling

Ach not released properly

Question 20

Where in the synaptic release process does LEMS attack?

Answer 20

Presynaptic calcium channels– antibodies

Question 21

Where in the synaptic release process does Botulinum and tetanus toxic interfere with?

Answer 21

interfere with SNARE proteins – vesicle fusion to pre-synaptic membrane of synapse.

Question 22

What are the downstream effects of a lesion of an axon?

Answer 22

1. degeneration of distal part of axon

2. degeneration of downstream cell body (next neuron)

Question 23

CNS has 4 types of support cells.

Neuroepithelium develops into–>

Answer 23

ependymal cells, oligodendrocytes and astrocytes

Question 24

microglia

Answer 24

macrophage- monocyte origin.

Do not come from CNS– originates from outside of neural tube

Question 25

ependymal cells

Answer 25

epithelial cells that line the ventricles of the brain and spinal canal (spinal cord) picky barrier for CSF movement Consist of microvilli and cilia

Question 26

Choroid plexus

Answer 26

ependymal cells are modified to form special secretory epithelium. produces CSF

Question 27

Astrocytes

Answer 27

star shaped (histology) lies between capillaries and neurons lies between neurons and pia mater Unique organelle; glial fibrillary acidic protein (GFAP) -- makes up glial filaments (intermediate filaments) serve as K+ sinks and regulate the ionic environment (via gap junctions) Found around nodes of ranvier Found around synapse - may ensure OR terminate synaptic transmission - neurotransmitter receptors on some astrocytes

Question 28

Astrocytes and blood brain barrier?

Answer 28

Are not themselves responsible for the barrier but it does control substances necessary to make the BBB.

Question 29

Astrocytes in an immune response?

Answer 29

divide and remove neuronal debris

Question 30

oligodendrocytes

Answer 30

myelin producing cells of CNS

Question 31

Myelination process?

Answer 31

oligodendrocyte sends out processes (40-50) that wrap axons in a spiral manner.

Question 32

Proteolipid protein

Answer 32

keep two arms wrapping around axon together.

Question 33

Schwann cells

Answer 33

support the PNS - when associated with peripheral nerves = schwann cells - when associated with cell bodies = satellite cells Surround ALL peripheral neurons (myelinated or non-myelinated) - produce growth factors and phagocytose debris at lesion sites. - most commonly known for covering and myelinating peripheral neurons

Question 34

what happens when a schwann cell is lesioned?

Answer 34

one Schwann cell = 1 internodal segment Death on 1 schwann cell is not as bad as a death of an astrocyte.

Question 35

Po

Answer 35

adhering protein of the PNS | -holds two arms of schwann cell that is wrapping around axon

Question 36

histology: Endonerium

Answer 36

Connective tissue - inner most coat of loose CT that surrounds axon and schwann cell

Question 37

histology: perineruium

Answer 37

modified dense fibrous CT with contractile cells that form a semipermeable barrier - axon (more than 1) - Schwann cell - endoneurium form fasicles

Question 38

histology : epineurium

Answer 38

contains many fasicles

Question 39

Major differences between CNS and PNS

Answer 39

1. CNS unmyelinated axons have no form of ensheathment 2. In CNS one oligodendrocyte forms many internodes. In PNS one Schwann cell forms one internode 3. PNS unmyelinated and myelinated axon are covered by Schwann cells (covered by basal lamina and CT coats)

Question 40

If PNS is lesioned, reconnections between the lesioned neurons may occur IF:

Answer 40

If basal lamina, endoneurium, perineurium and epineurium are intact. -grow along tubes Schwann cells provide the growth factors.