Glia - form and function Flashcards Preview

Foundations of Neuroscience > Glia - form and function > Flashcards

Flashcards in Glia - form and function Deck (37):
1

How many more glia are there than neurones in a human brain?

10x more glia

2

What do glia offer?

Physical support
Metabolic support
Electrical insulation
Guiding connections

3

How are glia noticeable?

They cannot be seen by electrophysiological techniques
Morphology
Expression specific markers
Immunohistochemical identification

4

What are the two divisions of glia?

Macroglia
Microglia

5

Name the 4 types of macroglia

Schwann cells
Oligodendrocytes
Ependymal cells
Astrocytes

6

Which two cells form myelin?

Schwann cells
Oligodendrocytes

7

What are the differences between Schwann cells and oligodendrocytes?

Schwann cells are in the peripheral nervous system
Oligodendrocytes are in the central nervous system
Schwann cells myelinate one axon
Oligodendrocytes myelinate many axons (up to 30)

8

What does myelination promote?

Regeneration

9

Can axen regeneration occur in the PNS or CNS?

PNS = yes
CNS = no

10

What allows axon regeneration in the PNS?

Schwann cells and endoneurial tube surrounding the axon encourage growth

11

What stops axon regeneration in the CNS?

No endoneurial tube
Prevented by signalling in CNS

12

What is the role of an ependymal cell?

Form the walls of the ventricles in the brain and central canal of the spinal cord
Produce cerebrospinal fluid

13

What structural adaptations do ependymal cells have?

They are ciliated
Helps circulate the cerebrospinal fluid

14

Describe an astrocyte

Largest glial cell
Most numerous glial cell

15

What is the function of an astrocyte?

Neuronal guidance during development
Form architecture of brain and spinal cord

16

What are astroglia stem cells responsible for?

Adult neurogenesis
Gliogenesis

17

What role do astrocytes play in homeostasis?

K+ buffering in extracellular fluid

18

How do astrocytes buffer K+

They have express transporters to take up K+ ions

19

Why do astrocytes buffer K+

Prevent accumulation of K+ as a result of neuron firing

20

How do astrocytes work alongside synapses?

They express neurotransmitter transporters
Prevent diffusion outside of the synapse

21

How do the astrocytes protect the synapse?

They express various transporters
Prevent entry from outside of the synapse
Protect synapse from extracellular fluid

22

What do astrocytes create at the synaptic junction?

A synaptic microenvironment

23

Explain neurovascular coupling

The 'foot' of the astrocyte envelops the capillaries and neurons
Provides energy to the neurons
Essential in highly active neurons

24

What can the astrocyte modulate?

Cerebral blood flow

25

What is cerebral blood flow and indirect measure of?

Neuronal activity

26

What does a damaged astrocyte release?

ATP and glutamate

27

How does the astrocyte cell respond to damage?

Hypertrophy
Proliferation

28

What is the name given to the proliferation of astrocytes in response to damage?

Reactive astrogliosis

29

What do astrocytes form in the CNS when damaged?

Glial scars

30

What does an astrocyte produce when an axon is damaged?

Inhibitory molecules to prevent growth

31

Describe a microglia

Smallest glial cell
10% of glial cells

32

What is the role of microglia?

Immune cell of the CNS

33

Where do microglia originate from?

Bone marrow monocytes

34

When do microglia migrate to the nervous system?

During development

35

How does a microglia work?

Motile processes monitor environment
Signals of disease or injury trigger transformation into phagocytic cell

36

What is reactive microgliosis?

The activation of microglia into phagocytic cells

37

CNS immune system and injury repair is carried out by which glial cell?

Microglia