L13 Neurons and Glia

Question 1

what is the MAIN difference between neurons and glia?

Answer 1

the mean they transfer information

Question 2

how are neurons and glia similar?

Answer 2

• resting membrane potential fluctuations
• gap junctions
• receptors
• voltage gated ion channels
• transporters
• pumps
• calcium signaling
• transmitters

Question 3

what are the differences between neurons and glia?

Answer 3

neurons - generate action potentials and excitatory/inhibitory posysynaptic graded postentials

Glia - intra- and inter-cellular calcium signaling

Question 4

what are the structural classifications of neurons?

Answer 4

neuron structure and function are related
there are different types of neuronal structure - i.e. striatal spiny neurons
*they don’t all look exactly alike, but most of them share common characteristics - soma, dendrite, axon etc.

Question 5

what is neuron morphology related to?

Answer 5

signal receptor and transmission!

Question 6

what is an example of multipolar neuron?

Answer 6

many dendrites, 1 axon

CNS - brain and spinal cord = motor n. in spinal cord anterior horn

Question 7

what are examples of bipolar neuron?

Answer 7

sensory neurons

retinal bipolar cells

Question 8

what are examples of pseudo-unipolar neurons?

Answer 8

sensory neurons in DRG

baroreceptor-sensitive cells in nodose ganglion?

Question 9

what is a Nissl body?

Answer 9

histological sign of rough ER, site of protein synthesis

Question 10

what makes up neurites?

Answer 10

the axon and the dendrite

Question 11

what connects the soma to the axon?

Answer 11

axon hillock/initial segment

Question 12

what is a synaptic bouton?

Answer 12

contains NTs waiting to undergo exocytosis

Question 13

what do neurons form?

Answer 13

networks

Question 14

what is an efferent neuron?

Answer 14

info from CNS to PNS = motor neuron

Question 15

what is an afferent neuron?

Answer 15

info from PNS to CNS = sensory neuron

Question 16

what are interneurons?

Answer 16

info with the CNS or within the PNS

Question 17

the size the neuron diameter is directly related to what?

Answer 17

the speed of conduction

*note - myelin is considered in diameter size
myelin speed up rate of conduction!

the larger the diameter, the faster the conduction

Question 18

what is the role of the cytoskeleton?

Answer 18

traffics material between soma and neurites

and support/maintain neuronal shape

Question 19

what makes up the cytoskeleton?

Answer 19

• microtubules
• neurofilaments (intermediate filaments)
• microfilaments

Question 20

what are the 3 filaments of the cytoskeleton joined to?

Answer 20

• eachother
• ER
• vesicles

BY PROTEIN bridges

Question 21

how does the cytoskeleton traffic materials?

Answer 21

anterograde axonal transport - soma to nerve ending

retrograde transport - nerve ending to soma

Question 22

what drives anterograde transport?

Answer 22

kinesin

Question 23

what drives retrograde transport?

Answer 23

dynein

Question 24

what material are transported in fast and slow anterograde transport?

Answer 24

fast- vesicles, mitochondria

slow - cytoskeleton molecules, soluble proteins and enzymes

Question 25

what materials are transported in retrograde transport?

Answer 25

lysosomes enzymes recycled vesicular membrane

Question 26

what viruses use retrograde transport along microtubules to inject neurons?

Answer 26

- herpes virus - polio virus - rabies virus - parvovirus

Question 27

what are types of glia in CNS?

Answer 27

``` astrocytes microglia oligodendrocytes ependymal cells tanycytes choroidal epithelial cells perivascular astrocytes perivascular microglia ```

Question 28

what are types of glia in PNS?

Answer 28

Schwann cells peripheral astrocytes/enteric glia satellite glial cells

Question 29

what is the function of CNS Astrocytes?

Answer 29

- maintain cerebral blood flow and ionic osmotic balances - store glycogen and supply neurons with lactate for energy - reg. K+ in microenvironment of neurons - release and take up NT - send info as intra- and intercellular calcium waves - release GF - major site of cholesterol synthesis in brain!

Question 30

what supports the formation of neuronal synapses (synaptic plasticity)?

Answer 30

cholesterol - secreted as APO-E containing HDL like particles

Question 31

how does CNS astroglial cells regulate K+ concentration?

Answer 31

rise in K+ prevented by removal of K+ via pump and transporter protein

Question 32

what are the macrophages of the CNS?

Answer 32

microglia

Question 33

what have lately played a role in reg. inflammatory system for astrocytes?

Answer 33

microglia

Question 34

what are microglia?

Answer 34

immunocompetent and phagocytic cells in the CNS ,which in the event of injury, inflammation and disease, become activated, reactive

Question 35

what myelinates CNS axons?

Answer 35

oligodendrocytes | can wrap MANY axons per cell

Question 36

what generates oligodendrocytes?

Answer 36

progenitor cells

Question 37

why does saltatory conduction occur?

Answer 37

because of the nodes of Ranvier

Question 38

where do ependymal cells form?

Answer 38

the walls of brain ventricles

Question 39

what is the function of choroid plexus epithelial cells?

Answer 39

secrete CSF | transfer molecules from blood into CSF

Question 40

what are perivascular astrocytes?

Answer 40

associated with the neurovascular unit | responsible for maintaining cerebral blood flow and ionic and osmotic balances in brain

Question 41

what are tanycytes?

Answer 41

``` 4 seperate populations of bipolar cells possibly link CSF to neuroendocrine events also indicated as a class of neural stem/progenitor cells ```

Question 42

what are characteristics of Schwann cells?

Answer 42

- provide myelination - phagocytic activity - support PNS nerve regen. Can wrap 1 axon with cell

Question 43

what are enteric glia?

Answer 43

- in intrinsic ganglia of the digestive system - associated with neurons in the enteric NS - morpholigic and molecular similarities to CNS astrocytes

Question 44

what are satellite glial cells?

Answer 44

-surround neurons in sensory, sympathetic, and parasympathetic ganglia

Question 45

can axons in the PNS regenerate?

Answer 45

yes - schwann cells can re-myelinate the axon

Question 46

can axons in the CNS regenerate?

Answer 46

impossible..?

Question 47

what is Wallerian degeneration?

Answer 47

following injury distal to site of axonal damage

Question 48

what is chromatolysis?

Answer 48

axon is sectioned close to the cell body causing swelling and movement of cell organelles away from cell body

Question 49

what is anterograde degeneration

Answer 49

causes degeneration of the neuron postsynaptic to the damaged neuron

Question 50

what is retrograde degeneration

Answer 50

happens in neurons, sends inputs to the damaged neuron

Question 51

what happens in amyotrophic lateral sclerosis (ALS)?

Answer 51

loss on neurons

Question 52

what is glosis?

Answer 52

glial scar formation

Question 53

what are demyelination diseases?

Answer 53

HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) MS Guillain-Barre syndrome Charcot Marie Tooth disorder

Question 54

what are tumors of glial origin?

Answer 54

schwannoma | glioblastoma

Question 55

where are reactive astrocytes and activated microglia found?

Answer 55

found around degenerating neurons in various inflammatory or degenerative disorder in the CNS may play neurotixic or neuroprotective roles

Question 56

neuron are what type of cell?

Answer 56

excitable