Cell Neuroscience - Neurons and Glia - Part 1

Question 1

In neurons, the synaptic activity leads to ___ and ___. Glial cells lack the ability to ___.

Answer 1

• generation of action potentials
• excitatory or inhibitory postsynaptic potentials
• generate action potentials

Question 2

Both neurons and glia (as all cell types) have cellular functions regulated by ___ transients. Of the glial cells, especially ___ support prominent intra- and inter-cellular ___ signaling.

Answer 2

• calcium
• astrocytes
• calcium

Question 3

What are gliotransmitters?

Answer 3

• Neurotransmitters , such as Glutamate and ATP, that are released by astrocytes.

Question 4

Explain the significance of a tripartite synapse.

Answer 4

• Describes the close proximity between the synapses of the pre- and postsynaptic neuron and astrocyte endfeet.

Question 5

What occurs at the astrocyte endfeet?

Answer 5

Location where astrocytes regulate the amount of neurotransmitters in synaptic clefts by uptake of the excess neuronal transmitters via transporters

Question 6

Both neurons and glial cells are able to release specific neurotrophic factors, such as ___, ___, and ___, to support their survival. Specifically astroglia secrete ___ and ___, which are necessary for neuronal development and formation of synapses, and thus neuronal plasticity.

Answer 6

• glial cell-derived neurotrophic factor (GDNF)
• brain-derived growth factor (BDNF)
• neurotrophin-3 (NT-3)
• growth factors
• cholesterol

Question 7

Can neurons divide? Can glial cells divide?

Answer 7

• No

- Yes

Question 8

Can neurons regenerate? Can glial cell regenerate?

Answer 8

• yes

- yes

Question 9

Do glial cells have membrane potential?

Answer 9

YES

Question 10

Describe multipolar neurons. Where are they found?

Answer 10

• These neurons have dendrites and one long axon.

- Examples are found in brain and spinal cord (e.g. motor nerve in spinal cord anterior horn).

Question 11

Describe bipolar neurons. What are some examples?

Answer 11

• These have an elongated cell body and two processes, one is the axon, the other is ending in dendrites.
• Examples are e.g. sensory neurons and retinal bipolar cells.

Question 12

Describe pseudo-unipolar neurons. What are some examples?

Answer 12

• Two axon-type branches out of cell body, of which one is towards CNS, the other to PNS.
• Examples are the sensory neurons in dorsal root ganglia and baroreceptor-sensitive cells in the nodose ganglion.

Question 13

Describe unipolar axons. Where are they found?

Answer 13

This type is rare in mammalian vertebrates (axon arises from the same spot with dendrites).

Question 14

An Afferent Neuron is A neuron with an axon carrying impulses where?

Answer 14

inwards to the CNS

Question 15

An Efferent Neuron is A neuron with an axon carrying impulses where?

Answer 15

outwards from CNS

Question 16

What is an interneuron? Where are they found?

Answer 16

• A neuron which mediates information between two other
  neurons.

-Both CNS and PNS

Question 17

Does the CNS contain myelinated or unmyelinated nerves? Examples?

Answer 17

• The CNS contains relatively few unmyelinated nerve fibres, though thin unmyelinated axons can be found in the mammalian hippocampus and cortex.
• The optic nerve is an example of a pure white matter tract composed of completely myelinated axons, while e.g. corpus callosum contains both grey and white matter portions with a mixture of myelinated and unmyelinated axons.

Question 18

In the PNS there are many fibres, or regions of fibres, for which the Schwann cells do not form myelin. Examples are:

Answer 18

C fibers of nociceptors, postganglionic sympathetic fibres, and motor nerve terminals at neuromuscular junctions.

Question 19

glutamatergic neurons are (Exitatory/Inhibitory)

Answer 19

Excitatory

Question 20

GABAergic neurons are (Excitatory/Inhibitory)

Answer 20

Inhibitory

Question 21

The speed of the conduction depends on ___ and ___ of the nerve fibre.

Answer 21

• diameter

- myelination

Question 22

Microtubules grow by the addition of ___ dimers at their ___ ends

Answer 22

• tubulin

- positive

Question 23

In neurons, the microtubules behave as transport tracks for two axonal transport systems moving materials in opposite directions between the ___ and the ___.

Answer 23

• soma

- nerve ending

Question 24

In mature neurons the ___, notably the ___ proteins, stabilize the microtubules.

Answer 24

• microtubule-associated proteins (MAPs)

- tau

Question 25

Microtubules are polymers of what?.

Answer 25

α- , β- and γ-tubulin

Question 26

What creates the scaffolding of the cytoskeleton, and in neurons their number probably determines the axon’s diameter?

Answer 26

Neurofilaments

Question 27

What are some examples of Neurofilaments/Intermediate filaments?

Answer 27

• neuronal neurofilament group
• glial GFAP,
• nestin
• vimentin

Question 28

What are some examples of microfilaments

Answer 28

• Actin

- Spectrin

Question 29

___ has an active role in the synaptic vesicle endocytosis during vesicle recycling.

Answer 29

Actin

Question 30

This MAP is an ATPase responsible for fast anterograde transport from soma towards the positive end of the microtubules, nerve ending and is akin to myosin in muscle. What is it?

Answer 30

Kinesin

Question 31

Kinesin becomes inactivated in the nerve ending and is carried ___.

Answer 31

-back to the soma by retrograde axonal transport

Question 32

___ moves an organelle along the microtubule

Answer 32

Kinesin

Question 33

The ___ and ___ are packaged into vesicles, which are attached to microtubules to be carried to nerve terminals.

Answer 33

• propeptides

- enzymes