Chapter 2: Structure And Functions Of Cells Of The Nervous System Flashcards

1
Q

Central nervous system

A

Brain and spinal cord

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2
Q

Peripheral nervous system

A

Part of nervous system outside brain and spinal cord, including nerves attached to brain and spinal cord

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3
Q

Nerves

A

Bundles of individual neurons contained within protective membrane

  • relay sensory to CNS from body and motor info from CNS —> rest of body
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4
Q

Sensory Neurons

A

Neuron that detects changes in external or internal environment and sends info about these changes to CNS

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5
Q

Motor Neuron

A

Neuron located within CNS that controls contraction of muscle or secretion

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6
Q

Interneuron

A

Neuron located in CNS in between sensory and motor neurons

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7
Q

Nucleus

A

Structure in central region of cell, containing chromosomes

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8
Q

Soma

A

Long, thin, cylindrical structure that conveys info from soma of neuron to its terminal buttons

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9
Q

Dendrite

A

Branched, treelike structure attached to soma of a neuron

  • receives info from terminal buttons of other neurons
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10
Q

Axon

A

Long, thin, cylindrical strcuture that conveys info from soma of neuron to its terminal buttons

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11
Q

Myelin Sheath

A

Sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons

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12
Q

Terminal Button

A

Bud at end of branch of an axon

  • sends info to that neuron
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13
Q

Synapse

A

Junction between terminal button of an axon and membrane of another neuron

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14
Q

Axoplasmic Transport

A

Active process by which substances are propelled along microtubules that run the length of axon

*anterograde and retrograde

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15
Q

Anterograde Transport

A

In direction along an axon from cell body toward terminal buttons

  • remarkably fast (500mm per day)
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16
Q

Retrograde Transport

A

In direction along an axon from terminal buttons toward cell body

  • half as fast as anterograde transport
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17
Q

Neurotransmitter

A

Chemical that is released by terminal button

- can be + or - to another neuron

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18
Q

Membrane

A

Structure consisting principally of lipid molecules that defines outer boundaries of a cell and constitutes many of cell organelles

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19
Q

Cytoskeleton

A

Formed of microtubules and other protein fibers, linked to each other and forming cohesive mass that gives cell its shape

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20
Q

Microtubule

A

Long strand of bundles of protein filaments arranged around hollow core

  • involved in transporting substances from place to place within cell
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21
Q

Cytoplasm

A

Viscous, semiliquid substance contained in interior of cell

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22
Q

Chromosome

A

Strand of DNA, with associated proteins, found in nucleus

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23
Q

Gene

A

Functional unit of the chromosome, which directs synthesis of one or more proteins

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24
Q

Enzyme

A

Molecule that controls chemical reaction, combining or breaking substances

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25
Q

Mitochondria

A

Organelles that are responsible for extracting energy from nutrients

  • Produces ATP
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26
Q

Glia

A

Supporting cells of CNS

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27
Q

Astrocytes

A

Provides support for neurons in CNS, provides nutrients and other substances, and regulates chemical composition of ECF

  • can have aquaporin
  • “neuron glue”
  • surround and isolate synapses, limiting dispersion of NTs
  • phagocytosis
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28
Q

Phagocytosis

A

Process by which cells engulf and digest other cells or debris caused by cellular degeneration

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29
Q

Oligodendrocytes

A

Type of glial cell in CNS that form myelin sheath

  • Node of Ranvier
  • one oligodendrocyte can produce up to 50 segments of myelin
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30
Q

Node of Ranvier

A

Nakes portion of myelinated axon between adjacent oligodendroglia or Schwaan cells

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31
Q

Microglia

A

Smallest of glial cells

  • act as phagocytes and protect brain from invading microorganisms
  • involved in inflammatory reaction following brain trauma
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32
Q

Schwaan Cells

A

Cell in PNS that is wrapped around myelinated axon, providing one segment of its myelin sheath

  • each PNS myelin segment consists of a single Schwann cell
  • chemical composition of myelin differs between CNS and PNS
    - MS is autoimmune attack of myelin in CNS
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33
Q

Blood-Brain Barrier

A

Semipermeable barrier between blood and brain produced by cells in the walls of brain’s capillaries

  • not uniform throughout nervous system
  • regulates composition of ECF
  • made up of astrocyte feet and tight junction layer
  • lipid soluble go through, water- soluble don’t
    Ex. Area postrema
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34
Q

Membrane Potential

A

electrical charge across cell membrane

  • difference in electical potential inside and outside cell
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35
Q

Resting Potential

A

membrane potential of neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials

  • about 70mV in many neurons
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36
Q

Hyperpolarization

A

increase in membrane potential of cell, relative to normal resting potential

37
Q

Depolarization

A

reduction of membrane potential of cell, relative to normal resting potential

38
Q

Threshold of Excitation

A

value of membrane potential that must be reached to produce AP

39
Q

Action Potential

A

brief electrical impulses that provides basis for conduction of information along axon

40
Q

Electrical charge of membrane potential

A

balance between diffusion and electrostatic pressure

41
Q

Diffusion

A

Movement of molecules from regions of high concentration to regions of low concentration

42
Q

Electrostatic Pressure

A

Attractive force between atomic particles charged with opposite signs or repulsive force between atomic particles charges with same sign

43
Q

Ions

A

Charges molecules

44
Q

Intracellular Fluid

A

Fluid contained in cell

45
Q

Extracellular Fluid

A

Body fluids located outside the cell

46
Q

Sodium-Potassium Pump

A

Pumps 3 Na out of cell and K into cell

47
Q

Ion Channel

A

specialized protein molecule that permits specific ions to enter or leave cells

48
Q

Voltage-Dependent Ion Channel

A

Ion channel that opens or closes according to value of membrane potential

49
Q

All-or-None Law

A

Principle that once AP is triggered in an axon, it is propagated, without decrement, to end of fiber

50
Q

Rate Law

A

Principle that variations in intensity of stimulus and other info being transmitted in an axon are represented by variations in rate at which axons fire

51
Q

Decremental Conduction

A

When going through myelin sheath, size of electrical message decreases

52
Q

Saltatory Conduction

A

Conduction of AP by myelinated axons

-Node of Ranvier is only place on axon with Na-K pumps

53
Q

Another way to increase AP propogation speed

A

Increase diameter of neuron

54
Q

Adenosine Triphosphate (ATP)

A

a molecule of prime importance to cellular energy metabolism

- its breakdown liberates energy

55
Q

Area postrema

A

region of the medulla where the BBB is weak; poisons can be detected there and can initiate vomiting

56
Q

Synaptic Transmission

A

relaying messages from one neuron to another across synapse

57
Q

Postsynaptic Potential

A

alterations in membrane potential of postsynaptic neuron, produced by liberation of NT at synapse

58
Q

Binding Site

A

location on receptor protein to which ligand binds

59
Q

Ligand

A

chemical that binds with binding site of receptor

60
Q

Dendritic Spine

A

small bud on surface of dendrite, with which terminal button of another neurons forms a synapse

61
Q

Neurotransmitters exert effects by attaching to […]

A

Neurotransmitters exert effects by attaching to binding sites

62
Q

Presynaptic Membrane

A

membrane of terminal button that lies adjacent to postsynaptic membrane and through which NT is released

63
Q

Postsynaptic Membrane

A

cell membrane opposite terminal button in synapse

64
Q

[…] are made of membrane and filled with molecules

A

Synaptic vesicles are made of membrane and filled with molecules

65
Q

Synaptic Vesicles

A

small, hollow beadlike structure found in terminal buttons

- contains molecules of NT

66
Q

Release of Neurotransmitters

A

Released when synaptic vesicles fuse with membrane and break open, spilling content into synaptic cleft

67
Q

Postsynaptic Receptor

A

receptor molecule in postsynaptic membrane of synapse that contains binding site for NT

68
Q

Neurotransmitter-Dependent Ion Channel

A

ion channel that opens when molecule of NT bind with postsynaptic receptor

69
Q

Ionotropic Receptor

A

receptor that contain binding site for NT and ion channel that opens when molecule of NT attaches to binding site

70
Q

Metabotropic Receptor

A

receptor that contains binding site for NT

    - Activates enzyme that begins series of events that open ion channel elsewhere in membrane of cell when molecule of NT attaches to to binding site
   - G protein
   - Second Messenger
71
Q

G protein

A

protein couples to metabotropic receptor

- conveys messages to other molecules when ligand binds with and activates receptor

72
Q

Second Messenger

A

chemical produced when G protein activates on enzyme

- carries signal that results in opening of ion channel or causes other events to occur in cell

73
Q

Ion channels in postsynaptic membrane

A

Na+: most important source of EPSP
K+: IPSP
Cl-: opened by inhibitory NTs; works when membrane is already depolarized; IPSPs
Ca2+: EPSPs; NT release; activates enzymes

74
Q

Excitatory Presynaptic Potential (EPSP)

A

excitatory depolarization of postsynaptic membrane of synapse caused by liberation of NT by terminal button

75
Q

Inhibitory Postsynaptic Potential (IPSP)

A

inhibitory hyperpolarization of postsynaptic membrane of synapse caused by liberation of NT by terminal button

76
Q

Reuptake

A

reentry of NT released from terminal button back through its membrane

77
Q

Enzymatic Deactivation

A

destruction of NT by enzyme after release

ex. AChE deactivates ACh

78
Q

Neural Integration

A

process by which EPSPs and IPSPs summate and control rate of firing a neuron

79
Q

Rate of neuron firing controlled by excitatory and inhibitory input to its dendrites and soma

A
  • If activity of excitatory synapses goes up, rate of firing will increase
  • If activity of inhibitory synapses goes up, rate of firing will decrease
80
Q

Autoreceptors

A
  • Neurons which respond to NT that they release
  • Mostly regulates internal processes, such as synthesis and release of NTs
    - Inhibitory
81
Q

Axoaxonic Synapse

A

Alter amount of NT released by terminal buttons (much like AR)
- can produce presynaptic modulation

82
Q

Presynaptic Modulation

A
  • Presynaptic inhibition

- Presynaptic facilitation

83
Q

Presynaptic inhibition

A

reduces amount of NT released by postsynaptic terminal button

84
Q

Presynaptic Facilitation

A

increases amount of NT released by postsynaptic terminal

85
Q

Neuromodulators

A

chemicals released by neurons that travel farther and dispersed more widely than NTs
- most are peptides

86
Q

Peptide

A

chain of amino acids joined together by peptide bonds

87
Q

Hormones

A

secreted by endocrine glands or cells in various organs

    - distributed through bloodstream
     - target cells
88
Q

Target Cells

A

type of cell that is directly affected by hormone or other chemical signal

 - contain receptors for particular hormones
 - distributed through bloodstream