glia

Question 1

What are the four types of neuroglia in the central nervous system?

Answer 1

1) astrocytes
2) oligodendrocytes
3) microglia
4) ependyma

Question 2

What are the three types of neuroglia in the peripheral nervous system?

Answer 2

1) schwann cells
2) satellite cells
3) enteric glia

Question 3

What are neuroglia essential for?

Answer 3

support + nutrition of neurons

Question 4

astrocytes

Answer 4

multiple neuron supporting functions

Question 5

oligodendrocytes

Answer 5

form myelin

Question 6

microglia

Answer 6

1) phagocytic

2) immune cells

Question 7

ependyma

Answer 7

line ventricles

Question 8

What are the two types of schwann cells?

Answer 8

1) myelinating schwann cells

2) non-myelinating schwann cells

Question 9

satellite cells

Answer 9

astrocyte-like functions in peripheral nervous system ganglia

Question 10

enteric glia

Answer 10

astrocyte-like functions in the gastrointestinal tract

Question 11

enteric glia

Answer 11

astrocyte-like functions in the gastrointestinal tract

Question 12

What does the blood-brain barrier do?

Answer 12

protects brain from harmful substances in blood

Question 13

What is the blood-brain barrier?

Answer 13

endothelial cells connected by tight junctions + surrounded by astrocyte processes

Question 14

Why is the central nervous system immune priveliged?

Answer 14

BBB prevents peripheral (systemic) immune cells from crossing body’s circulation into brain

Question 15

What type of neuroglia senses damage in the central nervous system?

Answer 15

microglia

Question 16

How do microglia become activated?

Answer 16

1) microglia continuously sampling environment
2) microglia detect damage + respond rapidly
3) regain macrophage-like status
4) regain immune functions
5) become phagocytic

Question 17

What is the ratio of schwann cells to axons?

Answer 17

1:1

Question 18

What is the ratio of oligodendrocytes to axons?

Answer 18

1:20-30

Question 19

What is the ratio of oligodendrocytes to axons?

Answer 19

1:20-30

Question 20

What is myelin made up of?

Answer 20

multiple layers of cell membrane (phospholipid bilayers)

Question 21

What are consecutive myelin sheaths separated by?

Answer 21

nodes of ranvier

Question 22

white matter

Answer 22

bundles of myelinated axons interconnecting brain regions

Question 23

demyelination

Answer 23

loss of myelin

Question 24

What does loss of myelin lead to?

Answer 24

axonal conduction block + degeneration

Question 25

What types of neuroglia are demyelinating diseases associated with?

Answer 25

1) oligodendrocytes | 2) schwann cells

Question 26

Why are astrocytes multifunctional?

Answer 26

specialised morphological + physiological features

Question 27

What intermediate filament do astrocytes express?

Answer 27

glial fibrillary acidic protein (GFAP)

Question 28

What do astrocytes connect?

Answer 28

neurons + blood vessels

Question 29

What is the main excitatory neurotransmitter in the brain?

Answer 29

glutamate

Question 30

glutamate-glutamine shuttle

Answer 30

1) astrocytes take up glutamate released at synapse 2) astrocytes convert glutamate to glutamine 3) release glutamine 4) taken up by presynaptic terminal 5) converted back to glutamate

Question 31

What does a high level of glutamate cause?

Answer 31

excitotoxicity

Question 32

excitotoxicity

Answer 32

destruction of neurons

Question 33

What ions do astrocytes take up during action potentials?

Answer 33

potassium, K⁺

Question 34

astrocyte-neuron lactate shuttle

Answer 34

1) astrocytes store glucose as glycogen 2) convert it to lactate when neurons need energy 3) release lactate for neurons

Question 35

Can nerves regenerate in the PNS?

Answer 35

yes

Question 36

Can nerves regenerate in the CNS?

Answer 36

no

Question 37

regeneration

Answer 37

1) schwann cells form regeneration tube | 2) guides + stimulates regrowth of axon

Question 38

What are the main functions of glia?

Answer 38

1) regulation of extracellular potassium 2) uptake of glutamate 3) injury responses 4) immune functions 5) myelination

Question 39

How does myelin increase speed of conduction in nerves?

Answer 39

provides electrical insulation