Lecture 19: Nervous Tissue (Structure and Function) Flashcards

1
Q

What are the 2 parts of the nervous system?

A

Central and peripheral

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2
Q

What are the 2 components of the central nervous system?

A

Brain and spinal cord

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3
Q

What are the 2 components of the peripheral nervous system?

A

Cranial nerves, spinal nerves and peripheral nerves

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4
Q

Where are 2 places that grey matter located?

A
  • Peripheral in brain and in areas called nuclei

- Central in spinal cord (H shaped / butterfly shaped)

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5
Q

What are the 5 components of grey matter?

A
Nerve cell bodies
Dendrites
Axon terminals
Non-myelinated axons
Neuroglia
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6
Q

Where are the 2 locations that white matter is located?

A

Central in brain

Peripheral in spinal cord

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7
Q

What does white matter consist of?

A

Myelinated material

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8
Q

What are the 3 parts of the axon in the CNS?

A

Cell body, dendrites and proximal part of the axon

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9
Q

What part of the neuron is part of the PNS?

A

Distal axon

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10
Q

In the CNS, what produces myelin for the axon?

A

Oligodendrocyte

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11
Q

In the PNS, what produces the myelin?

A

Schwann cell

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12
Q

What are the 4 types of neurons?

A

Motor
Sensory
Integrative
Anaxonic

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13
Q

Where is motor neurons located?

A

CNS to PNS

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14
Q

Where is sensory neurons located?

A

PNS towards CNS

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15
Q

Where is integrative neurons located?

A

CNS

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16
Q

Where are anaxonic neurons located?

A

Retina (some parts of CNS)

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17
Q

What is the function of motor neurons?

A

Send signals to effector tissues

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18
Q

What is the function of sensory neurons?

A

Send environmental signals to integrative centre

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19
Q

What is the function of integrative neurons?

A

Collate all information

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20
Q

What is the function of anaxonic neurons?

A

Acts as relays

21
Q

What are the 8 steps of neurotransmitter synthesis?

A
  1. Synthesis of neurotransmitter and formation of vesicles
  2. Transport neurotransmitter down the axon
  3. Action potential travels down the axon
  4. Action potential causes calcium to enter, evoking release of neurotransmitter
  5. Neurotransmitter attaches to receptor, exciting or inhibiting postsynaptic neuron
  6. Separation of neurotransmitter molecules from receptors
  7. Reuptake of neurotransmitter to be recycled
  8. Vesicles without neurotransmitter transported back to cell body
22
Q

What are the organizations of peripheral nerves?

A

Endometrium (loose) surrounds single nerve cells
Perineurium (loose) surrounds a fascicle (clusters of axons)
Epineurium (dense irregular) separates different types of nerves and fills spaces between fascicles
Paraneurium (fascia) separates nerves from surrounding structure

23
Q

What are the 4 steps of myelination?

A
  1. Axon sitting in a groove is surrounded by a Schwann cell
  2. Mesaxon membrane initiates myelination by surrounding the embedded axon
  3. Sheet like extension of the mesaxon membrane wraps successively around the axon, forming multiple membrane layers
  4. Cytoplasm is extruded from between the membranes - becomes compacted to form myelin
24
Q

What is the relationship between intermodal distance and axon size?

A

Larger internodal distance = larger axon diameter = fastest saltatory conduction

25
Q

What is the difference in speed of conduction in myelinated and unmyelinated nerve cells?

A

Unmyelinated is slower because no node of Ranvier, so cannot jump

26
Q

What are the 2 places where myelinated axons are found?

A

CNS and viscera

27
Q

Where is unmyelinated nerves found?

A

Periphery

28
Q

What are 6 types of glia cells found in the body?

A
  1. Oligodendrocytes
  2. Astrocytes
  3. Microglial cells
  4. Ependymal cells
  5. Schwann cells
  6. Satellite cells
29
Q

What is the function of oligodendrocytes?

A

Same as Schwann but in CNS - cytoplasmic processes from oligodendrocytes form flattened cytoplasmic sheaths that wrap around each axon BUT WRAPS AROUND MORE THAN ONE AXON SIMULTANEOUSLY

30
Q

What are the 3 functions of astrocytes?

A
  1. Have perivascular and perineural feet that contain gap junctions to provide biophysical support for endothelial cells
  2. Transport nutrients from blood to nerve cells
  3. Regulate nerve impulses by releasing gamma amino butyric acid near nodes of Ranvier
31
Q

Where are satellite cells found?

A

Sensory neuron cell bodies, not in CNS

32
Q

What are the 2 functions of satellite cells?

A

Same as astrocytes: provide support and transport nutrients

33
Q

What is the structure of astrocytes?

A

Star like

34
Q

What is the structure of microglial cells?

A

Large cells with elongated nucleus and relatively few processes emanating from cell body

35
Q

Where are microglial cells found?

A

Throughout CNS

36
Q

What are the 4 functions of microglial cells?

A
  1. Immune function
  2. Emote damaged nerve cells
  3. Sense increased K+ ions
  4. Digest protein tangles that are associated with dementia and Alzheimer’s
37
Q

Where are 2 locations that ependymal cells are found?

A

Line the spinal canal and ventricles of the brain

38
Q

What kind of cell is ependymal cell?

A

Cuboidal epithelial but look like columnar

39
Q

What are the 3cell surface specializations of ependymal cells?

A

Cilia and microvilli and tight junctions

40
Q

What is the overall function of ependymal cells?

A

Synthesize and secrete cerebrospinal fluid in the ventricles

41
Q

What is the function of cilia on ependymal cells?

A

Moves cerebrospinal fluid through ventricles to the spinal cord

42
Q

What are the 2 functions of microvilli on ependymal cells?

A

Absorb cerebrospinal fluid for removal of pathogens and present them to microglial cells and astrocytes

43
Q

What is the function of modified tight junctions between ependymal cells?

A

Control fluid release into brain

44
Q

How do you monitor molecular and cellular contents of brain?

A

Spinal tap

45
Q

What is the cause of multiple sclerosis?

A

Degenerative, caused by autoimmune degradation of myelin probably bc of Epstein Barr Virus, causing loss of conduction velocity, usually in CNS not peripheral

46
Q

What are 7 symptoms of multiple sclerosis?

A

Fatigue
Vision problems (diplopia - double vision)
Slurred speech (dysarthria)
Numbness and tingling sensations (paraesthesia)
Mobility issues (muscle spasms)
Urinary retention
Constipation

47
Q

What are 2 cells that can be found in PNS?

A

Schwann cells and satellite cells

48
Q

What are 4 cells that can be found in CNS?

A

Oligodendrocytes, astrocytes, microglial cells, ependymal cells