Chapter 12 Questions Based On Objectives Flashcards
1
Q
What are the two main subdivisions of the Nervous System?
A
2 parts
Central nervous system
Peripheral Nervous System
2
Q
What does the Central Nervous System consist of?
A
The Brain and the Spinal cord
3
Q
How much of the body mass is the nervous system?
A
3%
4
Q
The Nervous system is often described as?
A
The smallest and most complex out of the 11 systems
5
Q
How does the spinal cord connect to the brain anatomically?
A
through the foramen magnum of the occipital
6
Q
What composes the Peripheral Nervous System?
A
All nervous tissue outside the CNS
7
Q
How many cranial nerves are there?
A
12 pairs
8
Q
How many spinal nerves are there?
A
31 pairs
9
Q
What does ganglia mean?
A
Swelling
10
Q
Define sensory receptor
A
The term sensory receptor refers to a nervous system structure that monitors changes in the external or internal environment.
11
Q
Definition of ganglia
A
Small masses of nervous, consisting neuron cell body that are located outside of the brain and spinal cord
12
Q
Where are the enteric plexus located?
A
wall of organs of the GI
13
Q
What does the enteric plexus do
A
Help regulate the digestive system
14
Q
What are the three types of sensory receptors?
A
Touch receptor
Photo receptor
Olfactory
15
Q
What are the two sub-divisions of the PNS?
A
Somatic and Autonomic Nervous System
16
Q
Where does the SNS convey information to?
A
conveys output from the CNS to skeletal muscles only
17
Q
Where does the output of the ANS convey its output from? And to what 3 specific places?
A
Conveys output from the CNS to smooth muscle, cardiac muscle, and glands.
18
Q
Is the PNS voluntary or involuntary?
A
Voluntary
19
Q
Is the ANS voluntary or involuntary?
A
Involuntary
20
Q
What are the two main branches of the ANS
A
Sympathetic and Parasympathetic
21
Q
Is the fight-or-flight response the sympathetic or parasympathetic nervous system?
A
Sympathetic
22
Q
Is the rest-and-digest response the sympathetic or parasympathetic nervous system?
A
parasympathetic
23
Q
How are the sub-divisions of the PNS divided?
A
The sensory or afferent division
The motor or efferent division
24
Q
The motor or efferent division of the PNS conveys output from the CNS to _______
A
Effectors
25
The sensory or afferent division of the PNS conveys input into the CNS from____________ in the body
sensory receptors
26
What are the three basic functions of the nervous system?
Sensory function
Integrative functions
Motor functions
27
Out of the three functions of the nervous system, the sensory function can be described as ___________
Input or Processes or Output
Input
28
Out of the three functions of the nervous system, the Integrative function can be described as ___________
Input or Processes or Output
Processes
29
Out of the three functions of the nervous system, the motor function can be described as ___________
Input or Processes or Output
Output
30
What are the functions of the sensory receptors?
Sensory receptor detects internal stimuli.
31
How do the sensory receptors send messages to the brain?
Sensory information is carried into the brain and spinal cord through cranial and spinal nerves
32
What are the functions of the Integrative part of the nervous system?
Processes sensory info by analyzing it and making decision for appropriate response
33
What are the functions of the motor part of the nervous system?
Once the info is integrated, the nervous system sends the response
34
How does the nervous system send motor signals?
through cranial and spinal nerves
35
What are the two types of cells that comprise the nervous tissue?
Neuroglia
&
Neurons
36
Neurons possess electrical excitability, which means?
the ability to respond to a stimulus and convert it into an action potential
37
what is an action potential
electrical signal that travels through the membrane of the neuron
38
What does the Nissl Body of a neuron do?
Produce protein for the neuron
39
What is the Initial segment of a neuron?
Part of the axon closest to axon hillock.
40
Where is the trigger zone of a neuron?
Location where nerve impulses arise.
41
What is Axon collateral?
side branches of an axon
42
What is Varicosities?
String of swollen terminals
43
What is a Multipolar Neurons
Several dendrites and only one axon
44
What is a bipolar neuron?
one dendrite and one axon
45
What is a unipolar neuron?
dendrites and fused axon (continuous process)
46
Where do you find multipolar neuron?
Most neurons in the brain and spinal cord, and all of motor neurons.
47
Where do you find bipolar neurons?
Retina of eye, inner ear, and olfactory area of brain.
48
Where do you find unipolar neurons?
Dendrites are used for sensory receptors
Located in the ganglia of spinal and cranial nerves.
49
Functional Classification of Sensory Neurons
Contain sensory receptors at distal ends or after sensory receptors.
Most are unipolar.
50
Functional Classification of Motor Neurons
Convey action potentials away from CNS to effectors in the peripheral nervous system (PNS).
Multipolar in structure.
51
Functional Classification of interneurons
In the CNS, located between sensory and motor neurons.
Processes information from sensory neurons and then sends a motor response by activating motor neurons.
Most are multipolar in structure.
52
True/False
Neuroglia cells generate or propagate action potentials, but they can multiply.
True
53
Neuroglia cells can ________ to fill in spaces formerly occupied by degenerated neurons.
Multiply
54
What are the 6 different cells of the neuroglia?
Satellite Cells
Schwann Cells
Ependymal cells
Microglia
Oligodendrocytes
Astrocytes
55
What is the function of Astrocytes?
Structurally support neurons.
56
What is the function of Oligodendrocytes?
Forms and maintains myelin sheath around CNS axons.
57
What is the myelin sheath?
Are a multi-layer lipid and protein covering some axons, which insulates them and speeds up nerve impulses
58
What is the function of Microglia?
Remove cellular debris, phagocytize microbes, damaged nerve tissues.
59
What is the function of Ependymal cells?
Produce, monitor, and assist the circulation of cerebrospinal fluid.
&
Form blood-cerebrospinal fluid barrier.
60
What is the function of Schwann cells?
Form myelin sheath around axons
&
Participate in axon regeneration
61
What is the function of Satellite cells?
Provides structural support.
&
Regulate the exchange of materials between neuronal cell bodies and interstitial fluid.
62
Axons surrounded by myelin sheaths are said to be _________, and those without it are __________.
myelinated
&
unmyelinated
63
What are the functions of Neurolemma?
Aids in the regeneration of axons by forming a regeneration tube.
64
What are the Nodes of Ranvier?
Gaps in the myelin sheath
65
What are Clusters of Neuronal Cell Bodies called in the CNS?
Nucleus
66
What are Clusters of Neuronal Cell Bodies called in the PNS?
Ganglion
67
What are Bundles of Axons called in the CNS?
Tract
68
What is the function of tract axons?
Interconnects neurons in the spinal cord and brain.
69
What are Bundles of Axons called in the PNS?
Nerve
70
What is white matter composed of?
Composed of myelinated axons.
71
What is Grey matter composed of?
Composed of unmyelinated axons.
72
Which type of matter contains blood vessels?
White & Grey Matter
73
In the spinal cord, ______ matter surrounds a _______ matter core.
white
&
Gray
74
In the brain, _______matter covers the surface of the cerebrum and cerebellum.
Gray
75
Which type of matter contains neuronal bodies, dendrites, axon terminals, and neuroglia?
Gray
76
When are graded potentials used?
For short-distance communication.
77
What are the two types of action potentials?
Muscle Action Potential
Nerve Action Potential
78
Muscle Action Potential occurs where?
occurs in muscle fibers
79
Nerve Action Potential occurs in?
in a neuron
80
What are the two basic features of the plasma membrane of excitable cells?
Existence of resting membrane potential Presence of specific types of ion channels
81
What are the 4 types of ion channels
Leak Channels
Ligand-gated Channels
Mechanically-gated Channels
Voltage-gated Channels
82
What is a Leak Channel?
Gated channels that randomly open and closes.
83
Where do you find Leak Channels?
All cells, dendrites, cell bodies, and axons of all types of neurons.
84
What are Ligand-gated Channels?
Open in response to binding of ligand (chemical) stimulus.
85
Where do you find Ligand-gated Channels?
Dendrites of sensory receptors such as pain receptors, dendrites and cell bodies of interneurons and motor neurons.
86
What are Mechanically-gated Channels?
Open in response to mechanical stimulus (vibration), such as touch, pressure, vibration, tissue stretching.
87
Where do you find Mechanically-gated Channels?
Dendrites of sensory neurons such as touch receptors, pressure receptors, pain receptors.
88
What are Voltage-gated Channels?
Open in response to change in membrane potential (voltage stimulus).
89
Where do you find Voltage-gated Channels?
Axons of all types of neurons.
90
What is Resting Membrane Potential?
A cell exhibiting a membrane potential is said to be polarized (cytosol is more negative and extracellular fluid is more positive).
91
What are the three Factors leading to a membrane potential?
1. Unequal distribution of ions in the extracellular fluid and cytosol.
2. Inability of most anions to leave the cell.
3. Electrogenic nature of Na+-K+ ATPases.
92
What is a Graded Potential?
arises due to the small deviation from resting membrane potential that makes a membrane more (more negative) or less (less negative inside) polarized.
93
What are the two types of graded potentials?
Hyperpolarizing Graded Potential
Depolarizing Graded Potential
94
What is a Hyperpolarizing Graded Potential
When the response makes a membrane more polarized (more negative inside).
95
What is a Depolarizing Graded Potential?
When the response makes a membrane less polarized (less negative inside).
96
What is Decremental Conduction?
Graded potentials die out as they spread along the membrane.
97
What is Summation?
When graded potentials add together, potentials can become stronger and last longer.
98
What is Action potential (Impulse)?
sequence of rapidly occurring events that decrease and reverse the membrane potential and restores it to a resting state.
99
What are the 2 main phases of the generation of the action potential?
Depolarizing Phase
Repolarizing Phase
100
What is the Depolarizing Phase?
the negative membrane becomes less negative, reaches zero, then positive.
101
What is the Repolarizing Phase?
membrane potential is restored to resting state of -70 mV.
102
What is the After-hyperpolarizing phase?
After repolarizing, this event may occur, in which the membrane temporarily becomes more negative (< -70mV).
103
What is the threshold?
Action potential occurs in the axon of a neuron when depolarization reaches a certain level (~ -55mV).
104
What is Subthreshold Stimulus
Weak depolarization that does not cause an action potential.
105
What is Threshold Stimulus?
Stimulus strong enough to depolarize the membrane to the threshold.
106
What is Suprathreshold Stimulus?
– stimulus strong enough to depolarize above the threshold.
107
What are the 4 phases of an action potential?
1. Depolarizing Phase
2. Repolarizing Phase
3. After-hyperpolarizing Phase
4. Refractory Period
108
What is the depolarizing phase of an action potential?
the membrane becomes less negative -> positive.
109
What is the Repolarizing phase of an action potential?
K+ outflow causes membrane to go back to negative (-70 mV).
110
What is the After-hyperpolarizing Phase
too much K+ may cause the membrane to be less than -70 mV.
111
What is the Refractory Period?
A cell cannot generate another action potential.
112
What are the two types of Refractory Periods?
Absolute Refractory Period
Relative Refractory Period
113
What is the Absolute Refractory Period?
Even a strong stimulus cannot cause another action potential.
114
What is the Relative Refractory Period?
A second action potential can be produced only by a larger-than-normal stimulus.
115
What is Propagation of Action Potentials?
action potentials keep its strength as it spreads along the membrane. Action potentials regenerate over and over at adjacent regions of the membrane.
116
What is Continuous Conduction?
1. Step-by-step depolarization and repolarization of adjacent regions of the plasma membrane.
2. Ions flow through their voltage-gated channels.
3. Occurs in unmyelinated axons and muscle fibres.
117
What is Saltatory Conduction?
Occurs in myelinated axons (due to uneven distribution of voltage-gated channels).
Gated channels are present in the nodes of Ranvier (no axolemma).
Gates only open at nodes. Thus, more efficiently, less ATP is required to maintain Na+ and K+ concentration.
118
What are the 3 Factors Affecting the Speed of Propagation?
1. Amount of myelination
2. Axon Diameter
3. Temperature
119
How does the amount of myelination affect speed or propagation?
More myelin = faster propagation.
120
How does the axon diameter affect speed or propagation?
Larger diameters = faster propagation due to large surface area.
121
How does temperature affect speed or propagation?
Lower temperature = slower propagation.
122
The resting membrane potential arises from What three major factors?
1. Unequal distribution of ions in the ECF and cytosol.
2. Inability of most anions to leave the cell.
3. Electrogenic nature of the Na+–K+ ATPases.
123
What does the factor of Unequal distribution of ions in the ECF and cytosol, mean in terms of resting membrane?
As more and more positive potassium ions exit, the inside of the membrane becomes increasingly negative, and the outside of the membrane becomes increasingly positive.
124
What does the factor of the Inability of most anions to leave the cell, mean in terms of resting membrane potential?
Most anions inside the cell are not free to leave. They cannot follow the K+ out of the cell because they are attached to nondiffusible molecules such as ATP and large proteins.
125
What does the factor Electrogenic nature of the Na+–K+ ATPases mean in terms of resting membrane potential?
Since these pumps remove more positive charges from the cell than they bring into the cell, they are electrogenic, which means they contribute to the negativity of the resting membrane potential.
126
What is a Presynaptic Neuron?
– nerve cell that carries an impulse towards the synapse. It sends a signal.
127
What is a Postsynaptic Cell?
– cell that receives the signal.
128
What is a Postsynaptic Neuron?
– carries the nerve impulse away from the synapse.
129
What is an effector cell?
Responds to the impulse at the synapse.
130
What are the 3 types of synapses between neurons?
Axodendritic
Axosomatic
Axoaxonic
131
What type of synapse is from axon to dendrite?
Axodendritic
132
What type of synapse is from axon to cell body?
Axosomatic
133
What type of synapse is from axon to axon?
Axoaxonic
134
At an __________synapse, action potentials conduct directly between the plasma membranes of adjacent neurons through structures called gap junctions.
Electrical
135
Electrical synapses have two main advantages?
1. Faster communication
2. Synchronization
136
In the electrical synapses, a__________ contains tubular connexions, which are tunnels that connect the cytosol of two cells. Action potentials spread from cell to cell.
Gap junction
137
What are connexions?
Tunnels connect the cytosol of two cells. Action potentials spread from cell to cell.
138
What are chemical synapses?
the presynaptic and postsynaptic neurons do not touch, and are separated by synaptic cleft
139
True or false
Nerve impulses can conduct across the synaptic cleft.
False
140
What is the synaptic cleft filled with?
interstitial fluid
141
__________ diffuses through the fluid and binds to receptors of the postsynaptic neuron.
Neurotransmitter
142
What is Postsynaptic Potential?
– Converted from a chemical signal by the postsynaptic neuron.
143
Presynaptic neuron converts _______________signals (nerve impulse) into _________ signals (neurotransmitter).
Electrical
Chemical
144
The postsynaptic neuron receives the chemical signal and in turn produces a postsynaptic potential into what type of potential
Graded
145
Why do chemical synapses relay signals more slowly than electrical synapses?
Snaptic delay
146
What is an excitatory postsynaptic potential (EPSP)?
Depolarizing postsynaptic potential.
147
What is an Inhibitory Postsynaptic Potential (IPSP)?
Hyperpolarizing postsynaptic potential.
148
A neurotransmitter that causes ___________ of the postsynaptic membrane is excitatory because it is closer to the threshold.
Depolarization
149
The neurotransmitter that causes ________is inhibitory because it is further from the threshold.
hyperpolarization
150
An ionotropic receptor is a type of neurotransmitter receptor that contains both a _________ and an ________
Binding site and an ion channel
151
An ionotropic receptor is a type of__________channel
ligand-gated
152
In an isotropic receptor, what causes the ligand-gated channel to open?
Neurotransmitters
153
A metabotropic receptor is a type of neurotransmitter receptor that contains a neurotransmitter binding site but lacks________
Ion Channels
154
A metabotropic receptor is coupled to a separate ion channel by a type of membrane protein called a ______
G protein
155
What are the 3 ways a neurotransmitter is removed?
1. Diffusion
2. Enzymatic Degradation
3. Uptake by cells
156
What is Spatial Summation?
Summation of postsynaptic potentials due to stimuli occurring at different locations of the membrane at the same time.
157
What is Temporal Summation?
Summation of postsynaptic potentials due to stimuli occurring at the same location of the membrane at different times.
158
All the excitatory and inhibitory effects at any given time determine the effect on the postsynaptic neuron, which may respond in the following 3 ways
EPSP
Nerve Impulse(s)
IPSP
159
If the total excitatory effects are greater than the total inhibitory effects but less than the threshold level of stimulation, the result is an _________ that does not reach threshold
EPSP
160
If the total excitatory effects are greater than the total inhibitory effects and the threshold is reached, one or more ________ will be triggered.
Nerve impulses
161
If the total inhibitory effects are greater than the excitatory effects, the membrane becomes ___________
hyperpolarizes (IPSP)
162
What are Neurosecretory Cells
– Are neurotransmitters that secrete hormones.
163
The small-molecule neurotransmitters include? 6 of them,
Acetylcholine, amino acids, biogenic amines, ATP and other purines, nitric oxide, and carbon monoxide.
164
Is Acetylcholine an excitatory or inhibitory neurotransmitter?
Both
Excitatory neurotransmitter
&
Inhibitory neurotransmitter
165
When is Acetylcholine an excitatory neurotransmitter?
binding of ACh to ionotropic receptors open cation
channels.
166
When is Acetylcholine an inhibitory neurotransmitter?
binding to metabotropic receptors coupled to G Proteins
that open K+ channels.
167
What are the 2 types of amino acids neurotransmitters?
Gamma-aminobutyric acid (GABA)
Glutamate
168
Are the amino acids neurotransmitter GABA excitatory or inhibitory?
Inhibitory neurotransmitters.
169
Are the amino acids neurotransmitter Glutamate excitatory or inhibitory?
Excitatory effects.
170
What are the 4 types of biogenic amines?
Norepinephrine (NE) and Epinephrine
Dopamine (DA)
Catecholamines
Serotonin (5-HT)
171
What are biogenic Amines?
- Bind to metabotropic receptors causing either excitation or inhibition.
172
What are Neuropeptides?
Found in CNS and PNS; bind to metabotropic receptors and have excitatory and inhibitory effects.
173
What are Enkephalins?
Inhibit pain impulses by suppressing the release of substance P.
174
What are Endorphins?
Inhibit pain by blocking the release of substance P.
175
What is a Simple Series Circuit Type of Neural Circuit?
Presynaptic Neuron stimulates a single postsynaptic neuron.
176
What is a Diverging Circuit Type of Neural Circuit?
Nerve impulses from a single presynaptic neuron causes stimulation of increasing numbers of cells along the circuit.
177
What is a Converging Circuit Type of Neural Circuit?
Postsynaptic neuron receives nerve impulses from several different sources.
178
What is a Reverberating Circuit Type of Neural Circuit?
-Incoming impulse stimulates the first neuron, then the second, third, and so on.
-Sends impulses back through the circuit again and again.
179
What is a Parallel After-Discharge Circuit Type of Neural Circuit?
Single presynaptic cell stimulates group of neurons, each which synapses with a common postsynaptic cell.
