Glia 3

Question 1

Main functions of astrocytes?

Answer 1

Pathway formation, support, growth & death, Ca2+ signalling, glutamate involvement, BBB, K+ and glucose transport, channels and receptors and extracellular functions

Question 2

Role of astrocytes in pathway formation?

Answer 2

During development astrocytes provide the pathways used by neurons to migrate to their appropriate sites

Question 3

Which cells can produce the adhesion molecules needed in neuronal pathfinding?

Answer 3

Astrocytes

Question 4

Role of astrocytes in structural support?

Answer 4

Gives the synapse a physical form and structure

Question 5

Effects of astrocytes on the molecules in a synapse?

Answer 5

Keeps molecules in the synapse
Regulates molecules taken up by the synapse

Question 6

Role of astrocytes in growth?

Answer 6

Releases factors including growth factors, cytokines
Important for survival and development of neurons

Question 7

Role of astrocytes in damage repair?

Answer 7

Proliferate around the site to aid repair, or form a glial scar

Question 8

What are glial scars used for?

Answer 8

inhibit axonal regeneration

Question 9

How are astrocytes around neurons linked?

Answer 9

Gap junctions

Question 10

What do gap junctions between astrocytes allow?

Answer 10

Movement of various ions (Ca2+) between astrocytes

Question 11

WHat is a calcium wave?

Answer 11

A wave of Ca2+ passing through all the astrocytes around a neuron

Question 12

Purpose of a calcium wave?

Answer 12

Synchronising neurons

Question 13

Role of astrocytes involving glutamate?

Answer 13

Clear released glutamate

Question 14

Why is glutamate clearance by astrocytes important?

Answer 14

Prevention of excitotoxic cell death

Question 15

What happens to glutamate once it is taken up by astrocytes?

Answer 15

Converted to glutamine and returned to neurones

Question 16

How are astrocytes involved in the BBB?

Answer 16

Ensheath capillaries so all cells entering the brain must go through astrocytes

Question 17

What is immunological privellage?

Answer 17

No active immune system in the brain

Question 18

Astrocyte role in K+ and glucose transport?

Answer 18

They have uptake systems for K+ and glucose

Question 19

Why is glucose from astrocytes needed in neurons?

Answer 19

Needed for sodium potassium pump to maintain resting potential

Question 20

Astrocyte role in NTs?

Answer 20

Astrocytes express neurotransmitter receptors and channels (e.g. 5HT)

Question 21

Why do astrocytes express NT receptors and channels?

Answer 21

Unknown
May be used to coordinate neuronal activity

Question 22

Astrocyte function in extracellular volume?

Answer 22

Astrocytes can expand and shrink depending on how much water they uptake from the environment–> impacts the extracellular space

Question 23

How could an astrocyte increase NT effectiveness?

Answer 23

Swell so less space for synapse so higher conc of NT in synapse

Question 24

Which neuronal cells produce cytokines?

Answer 24

Astrocytes, microglia and neurons

Question 25

WHat can affect whether a cytokine has a pro or inflammatory response?

Answer 25

Point of release, cells they act upon, concentration, receptor they bind to

Question 26

Cytokines examples?

Answer 26

Interferons (IFN), interleukins(IL), tumour necrosis factor (TNF), transforming growth factors (TGF)

Question 27

Which cytokine receptor do microglia express?

Answer 27

IL6

Question 28

JAK STAT pathway?

Answer 28

Result of cytokine, ends up with triggering specific gene transcription