introduction to glia

Question 1

what are the two major classes of cells in the brain?

Answer 1

neurons and glia

Question 2

features of neurons?

Answer 2

electrically excitable, able to respond to external stimulation by generation of an action potential, capable of propagating through a neuronal network

Question 3

features of glia?

Answer 3

electrically non excitable, unable to generate action potential

Question 4

what do astrocytes do?

Answer 4

form a signalling and transport pathway between neurons and blood vessels

Question 5

what do astrocytes contain?

Answer 5

GFAP - glial fibrillary acidic protein

Question 6

types of glial cells?

Answer 6

NG2 expressing glia, microglia, schwann cells (glia of PNS)

Question 7

what do NG2 expressing glia do?

Answer 7

form contacts including synapses with neurons

Question 8

what do microglia do?

Answer 8

form the brain immune system, activated by injury and disease

Question 9

what are schwann cells?

Answer 9

ensheath terminal axon branches and synaptic boutons at the neuromuscular junction

Question 10

functions of astrocytes?

Answer 10

support, homeostasis, neurotransmitter uptake, maintenance of the BBB, transport and metabolism

Question 11

how do astrocytes perform homeostasis?

Answer 11

K+ buffering, water regulation, extracellular pH

Question 12

physiological properties of astrocytes?

Answer 12

don’t fire action potentials, have a high K+ resting conductance and a very negative resting membrane potential (-90mv), form a syncytium of cells connected by gap junctions, buffer/regulate extracellular K+ concentrations

Question 13

oligodendrocyte function?

Answer 13

make concentric lamellae of myelin which insulate axons. induce ion channel clustering at nodes of Ranvier. essential for axonal integrity

Question 14

microglia function?

Answer 14

brain defence and immune system