Neurocytology --review from M1 Flashcards Preview

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Flashcards in Neurocytology --review from M1 Deck (40):
1

PNS (compsition)

cranial nerves and spinal nerves

groups of neurons cluster in ganglion

2

CNS (composition)

Brain and spinal cord

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

3

Who are the glial cells in the PNS

satellite cells and schwann cells

4

who are the glial cells in the CNS

oligodendrocytes, astrocytes, ependymal cells, and microglia

5

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

Ectoderm

6

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

Ectoderm

7

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

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

8

What does the Neural tube develop into?

Brain and spinal cord

9

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

epithelium with cilia

Neurons and glia of the CNS

10

Function of Glia cells of CNS?

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

11

Multipolar cells

many branches off of soma.

found in large motor neurons

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

12

Pseudounipolar neuron

sensory neurons

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

13

Dendritic spines

on dendrites

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

14

What does the dendritic membrane do?

it sums excitatory and inhibitory information that reaches the neuron.

15

Histology: axon hillock

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

stains a pale pink

16

Histology: Nissle bodies

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

17

chemical synapse

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

Neuromuscular junction= Ach neurotransmitter

18

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

VAMP and t-SNAREs
- calcium sensing proteins

19

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

impaired vesicle recycling
( Ach not released properly)

20

Where in the synaptic release process does LEMS attack?

Presynaptic calcium channels-- antibodies

21

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

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

22

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

1. degeneration of distal part of axon
2. degeneration of downstream cell body (next neuron)

23

CNS has 4 types of support cells.

Neuroepithelium develops into-->

ependymal cells, oligodendrocytes and astrocytes

24

microglia

macrophage- monocyte origin.

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

25

ependymal cells

epithelial cells that line the ventricles of the brain and spinal canal (spinal cord)

picky barrier for CSF movement

Consist of microvilli and cilia

26

Choroid plexus

ependymal cells are modified to form special secretory epithelium.

produces CSF

27

Astrocytes

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

28

Astrocytes and blood brain barrier?

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

29

Astrocytes in an immune response?

divide and remove neuronal debris

30

oligodendrocytes

myelin producing cells of CNS

31

Myelination process?

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

32

Proteolipid protein

keep two arms wrapping around axon together.

33

Schwann cells

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

34

what happens when a schwann cell is lesioned?

one Schwann cell = 1 internodal segment

Death on 1 schwann cell is not as bad as a death of an astrocyte.

35

Po

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

36

histology: Endonerium

Connective tissue

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

37

histology: perineruium

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

form fasicles

38

histology : epineurium

contains many fasicles

39

Major differences between CNS and PNS

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)

40

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

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