Fundamentals of the Nervous System Flashcards

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1
Q

The master controlling and communicating system of the body

A

Nervous System

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2
Q

Functions of the nervous system:

A
  • Sensory Input
  • Integration
  • Motor Output
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3
Q

The two principle cell types of the nervous system are:

A
  1. Neurons

2. Supporting Cells (Neuroglial Cells)

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4
Q

Smaller cells that work with/ support neurons

A

Neuroglial

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5
Q

Part of neuron that receives information:

A

Dendrite

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6
Q

List the sequence of the nervous system

A

Sensory input–> Integration–> Motor Output

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7
Q

Has myelinated axons

A

White matter

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8
Q

Has unmyelinated axons or structures

-Includes cell body and dendrites

A

Gray Matter

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9
Q

Structural units of the nervous system

A

composed of body, axon, and dendrites

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10
Q

Characteristics of Neurons:

A
  • long-lived
  • amniotic
  • Have a high metabolic rate
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11
Q

Function in:

  • Electrical Signaling
  • Cell-to-cell signaling during development
A

Neural Plasma Membrane

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12
Q

Nerve cell body is also known as:

A

Perikaryon or soma

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13
Q

Characteristics of nerve cell body:

A
  • Has no centrioles (thus amniotic)
  • Has well-developed Nissl Bodies
  • Contains an axon hillock
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14
Q

Rough ER

-Appears to make the neurotransmitters of the neuron

A

Nissl Bodies

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15
Q

Slender processes branching form the hillock

A

Axon

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16
Q

Long axons are called:

A

Nerve Fibers

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17
Q

Secretory component of neuron

end of axon tail

A

Axon Terminal

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18
Q

Usually ___ unbranched axon per neuron

A

One

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19
Q

Functions of axons:

A
  • Generate and transmit action potential
  • Secrete neurotransmitters from the axonal terminals
  • Neurotransmitters initiate a neural impulse in the next neuron to excite particular muscles or glands
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20
Q

A neural impulse in the next neuron or excite a particular muscle or gland

A

Neurotransmitters

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21
Q

CNS

A
  • Brain

- Spinal Cord

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22
Q

PNS

A
  • Crainial Nerves

- Spinal Nerves

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23
Q

The supporting cells (neuroglia) have:

A

Many different types with specific functions

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24
Q
  • Produce myelin on peripheral myelinated neurons
  • Increase neurotransmission

*Not found in brain or spinal cord

A

Schwann Cells

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25
Q

Support clusters of neuron cell bodies (ganglia)

A

Satellite Cells

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26
Q
  • Most abundant, versatile, and highly branched glial cells
  • Mop up excess ions
  • Induce synapse formation
  • Connect neurons to blood vessels

*Found in CNS

A

Astrocyte

*Starburst

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27
Q
  • Found in CNS

- Are myelin-forming cells

A

Oligodendrocytes

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28
Q
  • Small, ovid cells with spiny processes

- Phagocytic cells of the CNS

A

Microglia

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29
Q
  • Range in shape from squamous to columnar
  • Ciliated cells of CNS
  • Line the central canal of the spinal cord and ventricles of the brian
A

Ependyma

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30
Q

Einstein has more ____ in his brain

A

More neuroglial (not more neurons)

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31
Q
  • Whitish, fatty (protein-lipoid), segmented sheath around most long axons
  • It functions to insulate the axon of a neuron
  • Make sure the neuron impulses run down the axon and stimulates the next cell
A

Myelin Sheath

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32
Q

___ is formed by Schwann cells in the PNS

A

Myelin

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33
Q

Remaining nucleus and cytoplasm of a Schwann Cell

A

Neurilemma

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34
Q
  • Gaps in the myelin sheath between adjacent Schwann cells

- They are sites where axon collaterals can emerge

A

Nodes of Ranvier (Neuorfibral Nodes)

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35
Q

In _____, there is no regeneration if you cut the axon

A

in spinal cord

*B/c oligodendrocytes do not divide

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36
Q

Both myelinated and unmyelinated fibers are present

A

Axons of the CNS

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37
Q

When myelin sheaths are formed in the CNS, they are formed by:

A

Oligodendrocytes

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38
Q

Two divisions of the Nervous System:

A
  • Sensory (afferent) division

- Motor (efferent) division

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39
Q

Two main systems in the Motor Division:

A
  • Somatic Nervous System

- Automatic Nervous System

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40
Q

Picks up sensory information and delivers it to CNS

A

Sensory (afferent division)

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41
Q

Carries info to skeletal muscle

A

Motor (efferent) division

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42
Q

Carries info to smooth muscle, cardiac muscle, and glands

A

Autonomic nervous system

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43
Q

Sensory Functions:

A

Sensory receptors gather info and info is carried to the CNS

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44
Q

Integrative Functions:

A

Sensory information used to create:

  • Sensations
  • Memories
  • Thoughts
  • Decisions
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45
Q

Motor Functions:

A
  • Decisions are acted upon

- Impulses are carried to effectors

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46
Q

What are effectors?

A

Muscles or glands

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47
Q

Structural differences of neurons:

A
  • Bipolar
  • Unipolar
  • Multipolar
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48
Q
  • Two processes

- In eyes, nose, and ears

A

Bipolar

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49
Q
  • One process

- Neural Ganglia

A

Unipolar

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50
Q
  • Many processes

- Significant component of the CNS

A

Multipolar

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51
Q

Functional differences of neurons:

A
  • Sensory Neurons
  • Interneurons
  • Motor neurons
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52
Q
  • Afferent neurons
  • Carry impulses to the CNS
  • Most are unipolar (some bipolar)
A

Sensory Neurons

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53
Q
  • Link neurons
  • Multipolar
  • Park of CNS (brain and spinal cord)
A

Interneurons

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54
Q
  • Multipolar

- Carry impulses away from the CNS to effectors (muscles and glands)

A

Motor Neurons

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55
Q

Neurons are highly _____

A

irritable

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56
Q

Action potentials, or nerve impulses, are generated from:

A

neurotransmitters

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57
Q

Neurotransmitters are released from:

A

synaptic bulb when stimulated by a neural impulse

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58
Q

Measure of electrical potential difference in energy

A

Voltage (V)

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59
Q

Voltage measured between two points

A

Potential Difference

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60
Q

The flow of electrical change between two points

A

Current (I)

61
Q

Hinderance to charge flow

A

Resistance (R)

62
Q

Electrical current in the body reflects the flow of ____ rather than electrons

A

ions

63
Q

There is a potential on either side of membranes when:

A
  • The number of ions is different across the membrane

- The membrane provides a resistance to ion flow

64
Q

What is resting membrane potential?

A

-70mV Millivolts

65
Q

At -70mV, there is a ____ concentration of Sodium outside the membrane

A

outside

66
Q

Types of plasma membrane ion channels:

A
  • Passive, or leakage, channels
  • Chemically gated channels
  • Voltage-gated channels
  • Mechanically gated channels
67
Q

Type of ion channel that is always open:

A

Passive, or leakage, channels

68
Q

Open with binding of a specific neurotransmitter

A

Chemically gated channels

69
Q

Open and close with response to membrane potential

A

Voltage-gated channels

70
Q

Open and close with response to physical deformation of receptors

A

Mechanically gated channels

71
Q

Operation of a Gated Channel

A
  • Example: Na+-K+ pump (gated channel)
  • Closed when a neurotransmitter is not bound to the extracellular receptor (Na+ cannot enter the cell and K+ cannot exit the cell)
  • Open when a neurotransmitter is attached to the receptor (Na+ enters the cell and K+ cannot exit the cell)
72
Q

Operation of a Voltage-Gated Channel

A
  • Example: Na+ channel
  • Closed when the intracellular environment is negative (Na+ cannot enter the cell)
  • Open when the intracellular environment is positive (Na+ can enter the cell)
73
Q

When gated channels are open:

A
  • Ions move quickly across the membrane
  • Movement is along their electrochemical gradients
  • An electrical current is created
  • Voltage changes across the membrane
74
Q

When gated channels open, and ions move across the membrane, they move along their ____

A

electrochemical gradient

75
Q

In gated channels, ions flow from an area of ___ to an area of _____

A

high concentration to an area of low concentration

76
Q

The potential difference (-70mV) across the membrane of a resting neuron is generated by different concentrations of:

A

Na+, K+, Cl-, and protein anions (A-)

77
Q

Ionic differences are the consequence of:

A
  • Differential permeability of the neurolemma to Na+ and K+

- Operation of the sodium-potassium pump

78
Q

Changes in membrane potential are created by three events:

A
  • Depolarization
  • Repolarization
  • Hyperpolarization
79
Q

The inside of the membrane becomes less negative

A

Depolarization

80
Q

the membrane returns to its resting membrane potential

A

Repolarization

81
Q

The inside of the membrane becomes more negative than the resting potential

A

Hyperpolarization

82
Q

Before you open gated channels, the inside is ___

A

more negative

83
Q

A ____ might not generate an action potential

A

weak stimulus

84
Q

Short-lived, local changes in membrane potential (cover a short distance)

A

Graded Potentials

85
Q

Graded potentials decrease in:

A

intensity with distance

86
Q

Graded potentials’ magnitude varies directly with:

A

the strength of the stimulus

87
Q

Sufficiently strong graded potentials can initiate:

A

action potentials

*ex: pebbles in a pond

88
Q

A brief reversal of membrane potential with a total amplitude of 100 mV

A

Action Potential (APs)

89
Q

Action potentials are only generated by:

A

muscle cells and neurons

90
Q

____ do not decrease in strength over distance

A

Action Potentials

91
Q

They are principle means of neural communication

A

Action Potentials

92
Q

An action potential in the axon of a neuron:

A

nerve impulse

93
Q

Na+ and K+ channels are closed

A

Action Potentials: Resting State

94
Q

In the resting state, ____ are closed and ____ are open

A

Activation gates are closed and inactivation gates are open

95
Q

In the Depolarization Phase, ____ gates are open, ____ gates are closed

A

Na+ gates are opened, K+ gates are closed

96
Q

A critical level of depolarization (-55 to -50 mV)

A

Threshold

97
Q

At threshold, depolarization becomes:

A

self-generating

*Dendrite= more +, so they want to get to a negative area, so they automatically flow down axon

98
Q
  • Sodium inactivation gates close
  • Membrane permeability to Na+ declines to resting levels
  • As sodium gates close, voltage-sensitive K+ gates open
  • K+ exits the cell and internal negativity is restored
A

Repolorization Phase

99
Q
  • Potassium gates remain open, causing an excessive efflux of K+
  • This efflux causes hyperpolorization of the membrane
  • The neuron is insensitive to stimulus and depolarization
A

Hyperpolorization

100
Q
  • Restores the resting electrical conditions of the neuron

- Does not restore the resting ionic conditions

A

Repolorization

101
Q

Restores resting ionic conditions

A

Sodium-Potassium Pump

102
Q

Describe sequence of events:

A
  • When open up chemically gated channel, sodium will move in
  • Sodium voltage gated channels open up (more sodium comes in)
  • We need to change membrane potential
  • to +30 in order to open up K+ voltage gated channel
  • K+ opens up, voltage gated channels form b/c APs form
  • When K+ opens, depolarization (potassium moving out) bc K+ is sensitive to 30+ mV
  • Sodium still in axon and continues to move down
  • Keeps occuring segmentally down length of axon at different voltage gates
  • Stimulate release of neurotransmitters
103
Q

Ions of the extracellular fluid move toward the area of greatest negative charge

  • A current is created that depolorizes the adjacent membrane in a foreword direction
  • The impulse propagates away from its point of origin
A

Propogation of an Action Potential

104
Q

The action potential moves:

A

away from the stimulus

105
Q

When sodium gates are closing, potassium gates:

A

are open and create current flow

106
Q

15 to 20 mV

A

Threshold

107
Q

Action potentials either happen completely or not at all (not stronger or weaker)

A

All-or-none phenomenon

108
Q
  • Established by the total amount of current flowing through the membrane
  • Weak (subthreshold) stimuli
  • Strong (threshold) stimuli
A

Threshold

109
Q

Not released into action potentials

A

Weak (subthreshold) stimuli

110
Q

Released into action potentials

A

Strong (threshold) stimuli

111
Q

All action potentials are alike and are:

A

independent of stimulus intensity

112
Q

Strong stimuli can generate an action potential more often than

A

weaker stimuli

113
Q

The CNS determines stimulus intensity by:

A

the frequency of impulse transmission

114
Q

Time from the opening of the Na+ activation gates until the closing of inactivation gates

A

Absolute Refractory Period

115
Q
  • Prevents the neuron from generating an action potential (while still generating first)
  • Ensures that each action potential is separate
  • Enforces one-way transmission of nerve impulses
A

Absolute Refractory Period

116
Q

The interval following the absolute refractory period when:

  • Sodium gates are closed
  • Potassium gates are open
  • Repolorization is occuring
  • The threshold level is elevated, allowing: strong stimuli to cause action potentials
A

Relative Refractory Period

117
Q

Extends from depolarization through hyperpolorization

A

Relative Refractory Period

118
Q

Rate of impulse propagation is determined by:

A
  • Axon diameter–> the greater the diameter, the faster the impulse
  • Presence of a myelin sheath–> myelination dramatically increases impulse speed
119
Q

Fluid-filled space separating the presynaptic and postsynaptic neurons

A

Synaptic Cleft

120
Q

Prevents nerve impulses from directly passing from one neuron to the next

A

Synaptic Cleft

121
Q

Transmission across the synaptic cleft:

A
  • Is a chemical event (as opposed to an electrical one)

- Ensures unidirectional communication between neurons

122
Q

Nerve impulses reach the axonal terminal of the presynaptic neuron and open ___ channels

A

Ca2+

*Bringing in Ca+ will stimulate vesticles to release neurotransmitters

123
Q

____ is

  • released into the synaptic cleft via exocytosis
  • Crosses the synaptic cleft
  • binds to receptors on the postsynaptic neuron
A

Neurotransmitter

124
Q

Neurotransmitter bound to a postsynaptic neuron:

A
  • Produces a continuous postsynaptic effect
  • Blocks reception of additional “messages”
  • Must be removed from its receptor
125
Q

Removal of neurotransmitters occurs when they:

A
  • Are degraded by enzymes
  • Are reabsorbed by astrocytes or the presynaptic terminals
  • Diffuse from the synaptic cleft
126
Q

The two types of graded postsynaptic potentials are:

A
  • EPSP

- IPSP

127
Q

A single EPSP _____ induce an action potential

A

cannot

128
Q

EPSPs must summate:

A

temporally or spacially

129
Q

An ____ depolarizes the membrane of postsynaptic neuron

A

EPSP

130
Q

Hyperpolorizes membrane of post synaptic neuron

A

IPSP

131
Q

Action potential of postsynaptic neuron becomes LESS likely

A

IPSP

132
Q

Action potential of postsynaptic neuron becomes MORE likely

A

EPSP

133
Q

EPSPs and IPSPs are added together in a process called

A

Summation

134
Q

More EPSPs lead to:

A

greater probability of action potential

135
Q

Chemicals used for neuronal communication with the body and the brain

A

Neurotransmitters

*classified chemically and functionally

136
Q
  • Acetylcholine (ACh)
  • Peptides
  • Novel Messengers
A

Chemical Neurotransmitters

137
Q
  • Degraded by the enzyme acetylcholinesterase
  • Biogenic Amines
  • Amino Acid
A

Acetylcholine

138
Q

ATP and dissolved gasses NO and CO

A

Novel Messengers

139
Q

Glycine, GABA, Glutamate

A

Amino Acids

140
Q

Dopamine, Serotonin, Epi

A

Biogenic Amine

141
Q

Encephaline (Endorphins)

A

Peptides (IPSP)

142
Q

Groups of interneurons that make synaptic connections with one another

A

Neuronal Pools

143
Q

Interneurons work together to perform:

A

A common function

144
Q
  • Neuron receives input from sensory neurons
  • incoming impulses represent information from difference types of sensory receptors
  • Allows nervous system to collect, process, and respond to info
  • Makes it possible for a neuron to sum impulses from different sources
A

Convergence

145
Q
  • One neuron sends impulses to several neurons

- Impulse from a single neuron in CNS may be amplified to activate enough motor units for a single muscle contraction

A

Divergence

146
Q

Membrane surrounding CNS

A

Meninges

147
Q

Three layers of meninges:

A
  • dura matter
  • arachnoid matter
  • pia matter
148
Q
  • Interconnected cavities
  • within cerebral hemispheres and brain stem
  • continuous with central canal of spinal cord
  • filled with cerebrospinal fluid (CSF)
A

Ventricles