Glia

Question 0

What is the function of the glucose-lactate shuttle?

Answer 0

Neurones do not store glycogen
Astrocytes store glycogen and use it to produce lactate, which can be transferred into neurones
Transferred to the neurone via MCT 1+2
Converted to pyruvate and metabolised
Supplement glucose supply, but the store still lasts only ~5 mins

Question 1

What are astrocytes?

Answer 1

Glial cells involved in structural support
Provide nutrition to neurones - glucose-lactate shuttle
Remove neurotransmitters from synapses, thereby controlling their concentration
Maintain ionic environment
Involved in blood brain barrier

Question 2

What are oligodendrocytes?

Answer 2

Glial cells forming the myelin sheath in the CNS

Question 3

What are microglia?

Answer 3

Immunocompetent cells
Activated when they recognise foreign material
Phagocytosis of debris and foreign material
Main defence of the brain, as normal immune responses are dampened

Question 4

What is the blood brain barrier?

Answer 4

Formed by endothelial cells in brain capillaries and the end feet of astrocyte processes
Water, oxygen and carbon dioxide move freely
Glucose, amino acids and ions are actively transported, allowing fine control of concentration

Question 5

CNS immune specialisation

Answer 5

Inflammation would be harmful inside a rigid skull
Microglia act as APCs
T cells can enter CNS, but the CNS inhibits the pro-inflammatory T cell response