2 - Cells of the CNS

Question 1

Immune cells of the CNS

Answer 1

Microglia

Question 2

Number of layers of neurons in the cortex

Answer 2

Six (shallowest is one, deepest is six)

Question 3

Ependymal cell location

Answer 3

Low columnar or cuboidal cells that line central canal of spinal cord and ventricles within brain .

Question 4

Role of ependymal cells

Answer 4

Some have cilia to aid CSF flow.

Lack a basal lamina

Question 5

Aspects of neurons that distinguish them from other cells
1
2
3
4

Answer 5

1) Specialised for signalling.
2) High levels of protein synthesis
3) Metabolically limited
4 Terminally differentiated

Question 6

Golgi stain

Answer 6

A type of silver stain, used to visualise neurons

Question 7

What regulates neuron morphology?

Answer 7

The cytoskeleton

Question 8

Components of cytoskeleton
1
2
3

Answer 8

1) Actin
2) Intermediate filaments
3) Microtubules

Question 9

Actin

Answer 9

Dynamic assembly/disassembly allows shape changes and movement (eg: spines and growth cones)

Question 10

Intermediate filaments

Answer 10

In all processes.

Permanent.

Question 11

Microtubules

Answer 11

Dynamic, composed of tubulin, involved in axon transport

Question 12

Alternative name for neuron cell body

Answer 12

Soma

Question 13

Why do neurons have high levels of protein production?

Answer 13

Protein required for ion channels, receptors, cytoskeleton

Question 14

Nissl bodies

Answer 14

Rough ER, free ribosomes in the cytoplasm of neurons.

Question 15

Astrocyte passive support functions (passive = respond to when neurons function)
1
2
3
4
5

Answer 15

1) Neurotransmitter uptake and degradation
2) K+ homeostasis
3) Neuronal energy supply
4) Maintenance of the BBB.
5) Injury response and recovery

Question 16

Astrocyte active functions
1
2

Answer 16

1) Modulation of neuronal function

2) Modulation of blood flow

Question 17

How do astrocytes supply glucose to neurons?

Answer 17

Wrap around blood vessels, take up glucose, deliver these to neurons

Question 18

Two crucially-important neurotransmitters in the brain

Answer 18

Glutamate and GABA

Question 19

How are glutamate and GABA removed from the brain?

Answer 19

Astrocytes have glutamate and GABA transporters, and remove neurotransmitters from synaptic cleft

Question 20

How are glial cells stimulated?
1
2
3
4

Answer 20

1) Neurotransmitters (ATP, glutamate)
2) Trauma
3) Spontaneous
4) Inflammatory mediators

These stimulate Ca2+ waves in glia (increased Ca2+ levels)

Question 21

How do glia communicate?

Answer 21

Glia contain synaptic vesicles and show exocytosis of gliotransmitters

Question 22

What happens to neurons when there is a glial Ca2+ wave?

Answer 22

Inhibition of adjacent neurons

Question 23

Effect of a Ca2+ wave in an astrocyte associated with a blood vessel

Answer 23

Leads to vasoconstriction OR vasodilation (depending on neural metabolic needs

Question 24

Function of oligodendrocytes

Answer 24

Responsible for myelination of CNS neurons.

Predominant glial cell of the white matter

Question 25

Structural difference between Schwann cells and oligodendrocytes

Answer 25

Oligodendrocytes extend processes that wrap around parts of several axons. Schwann cells wrap around one axon.

Question 26

Where do microglia come from?

Answer 26

Bone marrow

Question 27

Appearance of microglia

Answer 27

Large dendritic processes that extend from cell body

Question 28

``` Roles of microglia 1 2 3 4 ```

Answer 28

1) Constantly survey the CNS. 2) Change rapidly in response to inflammation or injury- upregulate cytokines/growth factors 3) May play a role in development and disease (lack of microglia alters mouse behaviour) 4) Phagocytic

Question 29

Structure of peripheral nerves 1 2 3

Answer 29

1) One or more bundles (fascicles) or nerve fibres. Each nerve within these fascicles (plus surrounding Schwann cell) is surrounded by endoneurium. 2 Each fascicle is surrounded by collagenous tissue called perineurium. 3) If there is more than one fascicle, than there is further layer of collagenous tissue called epineurium.

Question 30

Two types of ganglia

Answer 30

Sensory - House cell bodies of sensory neurons (EG dorsal root ganglia) Autonomic - Hose the cell body of post-ganglionic neurons (parasympathetic, sympathetic neurons)

Question 31

Ganglia

Answer 31

Aggregations of cell bodies of neurons outside the CNS

Question 32

Contents of ganglia

Answer 32

Cell bodies, nerve fibres, satellite cells