03-22 Glia and Neuroinflammation

Question 1

What percentage of CNS cells are glia?

Answer 1

~90% in the CNS!

Question 2

Glial celll

principal function

anatomical features that permit them to perform function

Question 3

Describe the concept of the tripartite synpase.

Answer 3

Astrocyte surrounds synapse to create special enviornment for signalling

Question 4

What is the role of glial cells in acute neural inflammation? Chronic?

Answer 4

acute neuroinflammation - astrocytes and microglia are activated; neutrophils maybe

chronic inflammation - endothelial cells, perivascular cells, circulating lymphocytes, and BBB

Question 5

Compare and contrast the histology of a neuron and a glial cell.

Answer 5

Neurons have larger, more euchromatic nuclei w/ prominent nucleoli

glial cells are much smaller with almost no cytoplasm and large heterochromatic nuclei

Question 6

What are the two categories of glia? What are they derived from?

Answer 6

Macroglia - from neuroectoderm

microglia - from monocyte/macrophage line; migrate into CNS from bone marrow before birth

Question 7

What is the Macroglia family tree? What are their functions?

Answer 7

• oligodendrocytes -axonal ensheathing/white matter cells
  
  • perineuronal oligos - found close to neurons in the gray matter; prolly don’t myelinate
  • interfasicular oligos - myelinate axons
• Astrocytes (see other f(x) slide) - many shapes/sizes (these subcats are way oversimplified):
  
  • fibrous - WM, long fibrs. round N’s of R
  • protoplasmic - GM; sheet-like processes surround synapses
• ependymal cells - help circulate CSF; ciliate tight columnar type along the lining of the ventricles and central canal
• radial glia - scaffolding in the developing CNS

Question 8

What is the f(x) of microglia?

Answer 8

Not totally sure

May phag apoptotic cells; activate in developing brain and quiescent until insult

Question 9

Where do glia
(not microglia) cells develop originally?

Answer 9

Subventricular zone (SVZ)

Question 10

What do Schwann cells do? Where do they come from?

Answer 10

glial cells of the PNS; come from neural crest cells

myelinate motor and sensory neurons; important components of the synapse at the NMJ; can ingest tissue debrise and promote regeneration

Question 11

What are some of the functions of astrocytes?

Answer 11

A. Structural support and scaffolding
especially during development
B. Extracellular potassium ion
concentrations.
C. Blood brain barrier and vascular
regulation
D. Tripartite synapse of pre- and post-
synaptic neurons together with
astrocytes
E. Trophic factors, neuropeptides, neurotransmitters,
inflammatory mediators
F. Produce extracellular matrix proteins
G. Detoxification by sequestering metals and other
neuroactive substances.
H. Calcium wave communication ?
I. Astrocytes may actively control the making and
breaking of synapses.
J. Multiple functions after neuropathological insults
K. Uptake and recycling of glutamate

Question 13

What are some dzs in which neuroinflammation plays a role?

Answer 13

Brain infections
Multiple sclerosis
Degnerative diseases
–Amyotrophic lateral sclerosis
–Alzheimer’s disease