NEUR 0010 - Chapter2 Flashcards

1
Q

What does a Nissl stain do?

A

Stains the nuclei of all cells, as well as the clumps (Nissl bodies) surrounding neuron nuclei

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2
Q

Why are Nissl stains useful?

A

Distinguish neurons from glia, allows for study of cytoarchitecture of brain tissue (arrangement of neurons)

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3
Q

What does a Golgi staid do?

A

Stains a small percentage of neurons, but includes their neurites

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4
Q

What are the two main characteristics of an axon and its branches?

A

Uniform diameter, branches at right angles

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5
Q

How many axons does a cell body usually emit?

A

Just one!

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6
Q

What is Golgi’s view of the neuron organization

A

Reticular doctrine: neurites fuse into a network

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7
Q

What is Cajal’s view of the neuron organization?

A

Neuron doctrine: never connect and communicate by contact rather than continuity

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8
Q

What does it mean to alternatively splice a segment of mRNA?

A

To splice out some exons with the introns, which codes for a different protein; thus the same stretch of transcripted mRNA can lead to different proteins after splicing

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9
Q

What organelle “abounds” in neurons?

A

Rough ER, more than in glial cells or non-neuronal cells

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10
Q

How do we know there’s tons of RER in neurons?

A

They’re the Nissl bodies! They get stained.

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11
Q

What organelle comprises Nissl bodies?

A

RER

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12
Q

Where is the major site of protein synthesis in neurons?

A

RER

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13
Q

What is the difference between proteins synthesized on free ribosomes vs RER ribosomes?

A

Free = stay in cytoplasm; RER = used in cell membrane or organelles, woven into the RER membrane to be transported elsewhere

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14
Q

Why is there so much RER in neurons?

A

Because RER-synth proteins are used in membranes of cells or organelles, which make special membrane proteins that are so characteristic of neurons

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15
Q

How does some SER impact protein translation?

A

Helps fold proteins that jut from the RER into their 3D structures

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16
Q

What does the Golgi apparatus do?

A

Post-translational chemical processing of proteins; sorts and delivers

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17
Q

What are the characteristics of microtubules in neurons?

A

Big, longitudinally down neurites; thick-walled pipe; composed of tubulin stacked like pearls (polymer)

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18
Q

What are MAPs?

A

Microtubule-associated proteins: regulate microtubule assembly and function; anchor microtubules to each other and neuron parts

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19
Q

What is tau?

A

Pathological changes in axonal MAP, which plays a role in Alzheimer’s dementia

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20
Q

What are the characteristics of microfilaments in neurons?

A

Thin, numerous and longitudinal in neurites; two strands of actin polymers; changes cell shape; closely associated with and anchored to the neuronal membrane

21
Q

What are the characteristics of neurofilaments in neurons?

A

Intermediate diameter; mechanically strong; multiple subunits (three woven protein strands) stacked

22
Q

What distinguishes the axon hillock from the soma?

A

No RER, few free ribosomes, different membrane protein composition

23
Q

What are axon collaterals?

A

Branches of the axon; often returns to communicate with the same cell that gave rise to it, or with neighboring dendrites (recurrent collaterals)

24
Q

What are recurrent collaterals?

A

Axon collaterals that return to the axon, or to neighboring dendrites

25
Q

How is axon diameter related to impulse speed?

A

Thicker axon, faster impulse

26
Q

What is the terminal arbor of the axon?

A

The area where several axon branches from the same axon connect to a dendrite/cell body in the same region

27
Q

What is boutons en passant?

A

When axons form synapses at swollen regions along their length and then continue to terminate elsewhere

28
Q

How does axon terminal cytoplasm differ from soma cytoplasm?

A

No microtubules, lots of synaptic vesicles, inside surface has dense protein covering, many mitochondria

29
Q

What is Wallerian degeneration?

A

Degeneration of axons when they’re separated from the soma (because they can’t make proteins, no ribosomes)

30
Q

How are proteins transported down the axon?

A

Walked by kinesins down the microtubules, fueled by ATP

31
Q

What is the difference between anterograde and retrograde transport?

A

Anterograde is soma to terminal, retrograde is terminal to soma

32
Q

How does transport protein involvement differ between anterograde and retrograde transport?

A

Anterograde recruits kinesin, retrograde recruits dynein

33
Q

What are dendritic spines?

A

Specialized structures on some dendrites that receive synaptic input; believed to isolate various chem reactions triggered by types of synaptic activation

34
Q

How do dendritic spines differ in mentally retarded infants from typically developed infants?

A

Less spines with metal retardation

35
Q

What is the main difference in cytoplasm for axons and dendrites?

A

Dendritic cytoplasm can contain polyribosomes just under the spines

36
Q

What is the significance of potential polyribosomes in dendritic cytoplasm?

A

That synaptic transmission can direct local protein synthesis in some neurons!

37
Q

How does one classify neurons by number of neurites?

A

Single neurite = unipolar; two neurites = bipolar; more neurites - multipolar

38
Q

Are the majority of neurons uni/bi/multipolar?

A

Multipolar

39
Q

How does one classify neurons by dendrites?

A

By their complex shapes, or by spiny/aspinous

40
Q

What are stellate vs pyramidal neurons?

A

Classes of neuron in cerebral cortex: star shaped or triangle shaped

41
Q

How does one classify neurons based on connections?

A

Primary sensory neurons (neurites in sensory surfaces); motor neurons (synapse with muscles); interneurons (connect to other neurons; majority of neurons are interneurons)

42
Q

How does one classify neurons based on axon length?

A

Golgi type 1 (long axons); Golgi tpye 2 (short axons)

43
Q

What is a cholinergic neuron?

A

Releases acetylcholine at the synapse; includes motor neurons that command voluntary movement

44
Q

What are astrocytes?

A

Glia: fill space, so influence neurite growth/retraction; regulates chemical content of extracellular space (like muffling synaptic junctions, removing neurotransmitters from synaptic cleft)

45
Q

What is a Schwann cell or oligodendroglial cell?

A

Insulate axons by wrapping them in myelin, interrupted by nodes of Ranvier

46
Q

How do oligodendroglia and Schwann cells differ?

A

Oligodendroglia are only in CNS, whereas Schwann are only in PNS; Oligodendroglia can myelinate multiple axons , but Schwann can only myelinate a single axon

47
Q

What are ependymal cells?

A

Line fluid-filled ventricles, help direct cell migration during brain development

48
Q

What are microglia?

A

Phagocytes to remove debris