Lecom - Nervous Tissue

Front 1

CNS develops from

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Neural Tube

Front 2

PNS and ANS develop from

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Neural crest

Front 3

In the CNS, a group of neurons with related functions is called

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nucleus

Front 4

Myelin in CNS is formed by

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Oligodendrocytes

Front 5

In the CNS, gray matter includes

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Neuronal cell bodies and processes
Astrocytes
Microglia
some oligodendroglia

Front 6

In the CNS, white matter includes

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myelinated axons

Front 7

These cells in the CNS line the ventricles of the brain and central canal of spinal cord

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ependymal cells

Front 8

These cells in the CNS secrete cerebrospinal fluid

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Choroid Plexus cells

Front 9

These are the phagocytic cells of the CNS.

What is their origin?

Back 9

microglia


Bone marrow

Front 10

What gives rise to neurons in CNS?

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Neural tube

Front 11

What gives rise to neurons in ANS and PNS?

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Neural crest

Front 12

The receptor region of a neuron includes

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cell body
dendrites

Front 13

The conductive region of a neuron includes

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axon
myelinating cells

Front 14

The effector region of a neuron includes

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telodendria

Front 15

Is a neuron an active cell? How can you tell?

Back 15

Yes highly active
Prominent nucleolus with euchromatic (light staining) nucleus

Front 16

Neuronal cytoplasm is typically acidophilic or basophilic?

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basophilic

Front 17

What are Nissl Bodies and how do they contribute to the appearance of a Neuron? What do they signify?

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clumps of RER and ribosomes

add to the basophlia of the cell

the high level of synthesis of membrane and secreted products

Front 18

What is a dendritic arborization?

What determines this?

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branches of dendrites
aka dendritic tree

the function of the neuron, and its relationships with other neurons

Front 19

Why does one tend to see the proximal parts of dendrites and not the distal parts when one uses a Nissl stain?

Back 19

There are more Nissl bodies closer to soma and gradually taper as the dendrite moves away from the body

Front 20

Where would a dendrite have more Nissl substance? Proximal or Distal to soma?

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Proximal

Front 21

What are dendritic spines? aka thorns or gemmules.

Where could they be found?

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specialized regions of synaptic contact

purkinje cells in cerebellum

Front 22

which synapses tend to have the most influence?

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those that occur closer to the cell body

Front 23

Do dendrites display an action potential? If no, what kind

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No

Graded

Front 24

Do axons stain with Nissl substance? Why or why not?

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No
They have no RER or ribosomes

Front 25

What is Nissl stain?

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Cressyl violet

Front 26

What angles do collateral branches of axons come off at?

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90

Front 27

Axons branch at ______ angles
Dendrites branch at ______ angles

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obtuse
acute

Front 28

What are terminal arborizations of axons called?

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Telodendria

Front 29

Why does a neuron need microtubules? neurofilaments?

Which are greater in number?

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Microtubules - important as tracks for fast anterograde and retrograde axonal transport

Neurofilaments are believed to be important in maintaining axonal diameter

neurofilaments are more abundant

Front 30

Slow axonal transport moves at a rate of ____mm/day

Back 30

.2 - 4

Front 31

will slow axonal transport be retrograde or anterograde?

Back 31

only anterograde

Front 32

What is the purpose of slow axonal transport?

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to convey structural elements
-Tubulin
-Neurofilament proteins
-Actin

Front 33

What facilitates the disassembly of neurofilament polymers the presynaptic cleft after slow AT has brought them there?

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high Ca level

Front 34

Fast axonal transport moves at a rate of _____mm/day

Back 34

20-400

Front 35

What does the anterograde aspect of Fast AT convey?

Give examples

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membranous organelles and membrane bound proteins

mitochondria, synaptic vessicles, SER

Front 36

What does the retrograde aspect of Fast AT convey?

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worn organelles and endocytosed materials, such as growth factors, toxins and viruses

Front 37

Which aspect of Fast AT uses kinesin as a motor protein?

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anterograde

Front 38

Which aspect of Fast AT uses dynin as a motor protein?

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retrograde

Front 39

Fast axonal transport is dependent on ________.

Back 39

microtubules

Front 40

Substances that disrupt microtubules or that prevent their assembly will prevent or inhibit ______ axonal transport

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fast

Front 41

This is the material that cannot be digested by lysosomes when substances are retrogradely transported back to the cell body

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lipofuchsin

Front 42

Which is the most common type of synapse in the nervous system

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chemical

Front 43

Which synapses allow neurons to act in unison by communicating via gap junctions

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electrical

Front 44

the influx of what ion promotes the exocytosis of synaptic vesicles

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Calcium

Front 45

This glial cell lines the ventricles and central canal

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ependymal cell

Front 46

These glial cells are found in the ventricles and secrete CSF

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choroid plexus cells

Front 47

These cells are responsible for myelinating CNS

Back 47

oligodendrocytes

Front 48

These are the phagocytic cells of the CNS.

From where are they derived?

Back 48

microglia


bone marrow

Front 49

These cells line the central canal of the spinal cord

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ependymal cells

Front 50

The choroid epithelium is made of what type of epithelium?
What apical specialization does it have?
What links the epithelial cells together?

Back 50

cuboidal
microvilli
Tight junctions

Front 51

Ependymal epithelium has what type of epithelial cell?
How are they linked together?
What apical specialization does it have?

Back 51

Cuboidal
Desmosomes
Microvilli

Front 52

What are tanycytes?
What specializations do they have on their basal surface?
How are they linked together?

Back 52

Specialized ependymal cells found in third ventricle.
They have basal processes that form endfeet on blood vessels.
They are linked to each other and to the ependymal epithelia by tight junctions

Front 53

Which astrocytes are typically found in white matter?

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Fibrous

Front 54

Which astrocytes have long slender processes composed of GFAP?

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Fibrous

Front 55

Which astrocytes form structural support for white matter tracts?

Back 55

Fibrous

Front 56

Which astrocytes are typically found in gray matter?

Back 56

protoplasmic

Front 57

Which astrocytes have short, thick, bushy processes?

Back 57

protoplasmic

Front 58

Which astrocytes stain less intensely with antibodies to GFAP?

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protoplasmic

Front 59

Which astrocytes have relatively fewer intermediate fillaments?

Back 59

protoplasmic

Front 60

Which astrocytes act as support cells for neurons?

Back 60

protoplasmic

Front 61

Which astrocytes make growth factors?

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protplasmic

Front 62

Which neuroglial cells scavenge ions and debris from neuron metabolism and supply energy for metabolism?

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Astrocytes

Front 63

which glial cells form a selective barrier between pia mater and nervous tissue of brain and spinal cord?

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Astrocytes

Front 64

Which glial cells proliferate to form scar tissue after injury to CNS?

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Astrocytes

Front 65

Which type of astrocyte helps establish the blood brain barrier?

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protoplasmic astrocyte

Front 66

Which cells induce capilaries to form the blood brain barrier?

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astrocytes

Front 67

This is the most common type of primary brain tumor. Comprises 80-90% of all glial tumors in adults

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Astrocytoma

Front 68

Astrocytomas have a tendancy to become more________ with time

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anaplastic

Front 69

Do astrocytomas tend to travel to tother parts of the CNS? metastasize to the rest of the body?

What is the mean survival for a person with an astrocytoma

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Yes
No

8-10 months

Front 70

These are the myelinating cells of the CNS

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oligodendrocytes

Front 71

The oligodendrocytes that act as satellite cells near neurons will also myelinate cells?

Back 71

No they dont appear to do that

Front 72

This is a chronic demyelinating disease of the CNS.

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Multiple Sclerosis

Front 73

Why are there reports of vision problems during the onset of Multiple Sclerosis

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optic nerve is myelinated by oligodendria.

Front 74

The plaques formed during MS are formed by

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astrocytes

Front 75

When do microglia migrate into the CNS

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during the development of CNS vasculature

Front 76

What do microglia do?

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respond to CNS injury by dividing and phagocytosing injured neurons and glia.

Front 77

What happens to the morphology of a microglial cell when CNS is injured?

What is this cell called?

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microglial nuclei enlarge and elongate

rod cell

Front 78

How do microglia act when there is increased dammage to CNS.

What are they called at this point?

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They become phagocytic

gitter cells

Front 79

Why is a CNS injury usually irreparable in adults?

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Astrocytes reacting to injury (gliosis) form a glial scar that inhibits axonal regeneration
Oligodendrocytes express a protein that prevents axonal growth

Front 80

This is the layer of fibrous dense CT that forms the eexternal coat of nerves

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epineurium

Front 81

This surrounds each bundle of nerve fibers (fascicle).

Back 81

Perineurium

Front 82

The inner surface of this CT layer in peripheral nerves consists of a layer of flattened cells joined by tight junctions (zonula occludens) that prohibits the passage of most macromolecules.

Back 82

perineurium

Front 83

This is a thin layer of reticular fibers, produced mainly by Schwann cells that surrounds individual nerve fibers

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endoneurium

Front 84

This layer of CT in nerves is the site of the blood nerve barrier

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perineurium

Front 85

This is an acute polyradiculoneuropathy that affects the myelin of the PNS resulting in bilateral symmetrical motor weakness

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Guillan-Barré Syndrome

Front 86

Guillan-Barré Syndrome affects the myelin of the PNS or the CNS?

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PNS

Front 87

Why do peripheral nerves regenerate best when crushed?

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their CT sheaths act as a guide for regeneration

Front 88

How do Schwann cells act during peripheral nerve regeneration?

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they become phagocytic and synthesize essential growth factors and cytokines

Front 89

peripheral nerves regenerate ata rate of ____mm/day

Back 89

1-3

Front 90

Describe what happens in nucleus after an axotomy.

Back 90

1. cell body swells
2. dissolution of Nissl substance - chromatolysis
3. nucleus moves to eccentric position
4. decrease in synthesis of less essential proteins - neurofilament, transmitter p.
5. increase in sythesis of actin and tubulin for axonal regeneration.

Front 91

Which genes are up-regulated during regenerative response?
Down-regulated?

Back 91

actin and tubulin are up-regulated b/c they are needed for growth cone and axon regneration

neurofilament genes and those involved in synaptic transmitters are down-regulated

Front 92

Describe what happens in axon during axonal regeneration after axotomy.

Back 92

1. Retrograde degeneration-proximal part degenerates back to last node of Ranvier.
2. Wallerian degeneration - distal portion degenerates completely b/c separated from synthetic machinery of cell (all of the remnants removed by macrophages)
3. Schwann cells proliferate forming column off of effector cell
4. Growth at distal end of proximal segments begins and regeneration successful if sprouting axon penetrates schwann cell column.

Front 93

What is the growth cone?

Back 93

Growth cone is a motile structure produced by axon after injury that has a concentration of receptors for neurotrophic factor and laminin.