Chapter 7: The Nervous System Flashcards
1
Q
What does CNS stand for?
A
Central nervous system
The CNS consists of the brain and spinal cord.
2
Q
What does PNS stand for?
A
Peripheral nervous system
The PNS includes nerves, ganglia, and nerve plexuses outside of the CNS.
3
Q
Define interneuron.
A
Multipolar neuron located entirely within the CNS
Interneurons play a critical role in reflexes and neural circuits.
4
Q
What is a sensory neuron?
A
Neuron that transmits impulses from a sensory receptor into the CNS
Sensory neurons are also known as afferent neurons.
5
Q
Define motor neuron.
A
Neuron that transmits impulses from the CNS to an effector organ
Motor neurons are also referred to as efferent neurons.
6
Q
What is a nerve?
A
Cable-like collection of many axons in the PNS
Nerves may be mixed, containing both sensory and motor fibers.
7
Q
What is the function of a somatic motor nerve?
A
Stimulates contraction of skeletal muscles
Somatic motor nerves are involved in voluntary movements.
8
Q
What does an autonomic motor nerve do?
A
Stimulates contraction (or inhibits contraction) of smooth muscle and cardiac muscle and stimulates glandular secretion
Autonomic motor nerves regulate involuntary body functions.
9
Q
Define ganglion.
A
Grouping of neuron cell bodies located outside the CNS
Ganglia act as relay points in the nervous system.
10
Q
What is a nucleus in the context of the nervous system?
A
Grouping of neuron cell bodies within the CNS
Nuclei serve various functions depending on their location.
11
Q
Define tract.
A
Grouping of axons that interconnect regions of the CNS
Tracts are essential for communication between different parts of the brain and spinal cord.
12
Q
What are the structural and functional units of the nervous system?
A
Neuron
Neurons are specialized cells responsible for transmitting information throughout the body.
13
Q
List the general functions of neurons.
A
- Respond to chemical and physical stimuli
- Conduct electrochemical impulses
- Release chemical regulators
- Enable perception of sensory stimuli
- Enable learning and memory
- Control muscles and glands
These functions illustrate the critical role neurons play in the nervous system.
14
Q
True or False: Most neurons can divide.
A
False
Most neurons cannot divide, but they have the ability to repair themselves.
15
Q
Fill in the blank: Neurons enable perception of sensory stimuli, ________, memory, and control of muscles and glands.
A
learning
Learning is one of the cognitive functions facilitated by neurons.
16
Q
What is the role of neurons in response to stimuli?
A
They respond to chemical and physical stimuli
This response is fundamental for the functioning of the nervous system.
17
Q
What type of impulses do neurons conduct?
A
Electrochemical impulses
These impulses are essential for communication within the nervous system.
18
Q
What do neurons release that affects other cells?
A
Chemical regulators
These regulators include neurotransmitters that influence various physiological processes.
19
Q
What is the structural classification of neurons that has multiple dendrites and one axon?
A
Multipolar
Multipolar neurons are the most common type in the central nervous system.
20
Q
What type of neuron has one dendrite and one axon?
A
Bipolar
Bipolar neurons are commonly found in sensory pathways, such as the retina.
21
Q
What is the term for a neuron with one process?
A
Pseudounipolar (unipolar)
Pseudounipolar neurons are often involved in sensory functions, such as touch and pain.
22
Q
Which type of neuron has multiple dendrites but no axon?
A
Anaxonic
Anaxonic neurons are primarily found in the brain and are involved in local signaling.
23
Q
Neuroglia
A
Support cells of the nervous system
24
Q
What are nerve growth factors?
A
Neurotrophins that promote neuronal growth in the fetal brain.
Nerve growth factors are essential for the development and maintenance of the nervous system.
25
What role do neurotrophins play in adults?
Aid in the maintenance of sympathetic ganglia and regeneration of sensory neurons.
## Footnote
Neurotrophins are crucial for the health and repair of neuronal tissues.
26
Who was Dr. Rita Levi-Montalcini?
An influential scientist known for her work on nerve growth factors.
## Footnote
Dr. Rita Levi-Montalcini received the Nobel Prize in Physiology or Medicine in 1986.
27
Fill in the blank: Nerve growth factors are also known as _______.
[neurotrophins]
28
True or False: Nerve growth factors are only important during fetal development.
False
## Footnote
Nerve growth factors continue to play a significant role in adults for neuronal maintenance and regeneration.
29
What is Guillain-Barre syndrome?
A rare neurological disorder where the body's immune system attacks the peripheral nervous system.
## Footnote
It often leads to muscle weakness and can result in paralysis.
30
What does AMAN stand for?
Acute Motor Axonal Neuropathy.
## Footnote
AMAN is a subtype of Guillain-Barre syndrome characterized by motor axonal damage.
31
What does AIDP stand for?
Acute Inflammatory Demyelinating Polyneuropathy.
## Footnote
AIDP is another subtype of Guillain-Barre syndrome, primarily affecting the myelin sheath of peripheral nerves.
32
True or False: Guillain-Barre syndrome can only occur as AIDP.
False.
## Footnote
Guillain-Barre syndrome can manifest as either AMAN or AIDP.
33
What are the two main types of Guillain-Barre syndrome?
* Acute Motor Axonal Neuropathy (AMAN)
* Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
## Footnote
These types differ in their pathological features and clinical presentations.
34
What is the Blood-Brain Barrier?
A selective barrier that regulates the passage of substances between the bloodstream and the brain.
35
Which substances are highly permeable through the Blood-Brain Barrier?
H2O, glucose, lipid-soluble substances such as O2, CO2, alcohol, caffeine, nicotine, and anesthetics.
36
What substances are slightly permeable through the Blood-Brain Barrier?
Na+, K+, Cl-, urea, and creatinine.
37
Fill in the blank: The Blood-Brain Barrier is highly permeable to _______.
H2O, glucose, lipid-soluble substances.
38
True or False: The Blood-Brain Barrier allows free passage of all ions.
False.
39
List substances that can easily cross the Blood-Brain Barrier.
* H2O
* Glucose
* O2
* CO2
* Alcohol
* Caffeine
* Nicotine
* Anesthetics
40
What is the permeability of the Blood-Brain Barrier to Na+, K+, Cl-, urea, and creatinine?
Slightly permeable.
41
Fill in the blank: The Blood-Brain Barrier is slightly permeable to _______.
Na+, K+, Cl-, urea, and creatinine.
42
What is the function of astrocytes?
Form blood-brain barrier, regulate extracellular environment, support neurotransmitter recycling
## Footnote
Astrocytes play a crucial role in maintaining homeostasis in the brain.
43
What is the primary role of microglia?
Phagocytose pathogens and debris
## Footnote
Microglia act as the immune cells of the central nervous system.
44
What do ependymal cells produce?
Cerebrospinal fluid
## Footnote
Ependymal cells line the ventricles of the brain and the central canal of the spinal cord.
45
What is the function of oligodendrocytes?
Form myelin sheaths in the CNS
## Footnote
Oligodendrocytes are essential for the insulation of axons in the central nervous system.
46
What do Schwann cells do?
Form myelin sheaths in the PNS
## Footnote
Schwann cells are responsible for myelination in the peripheral nervous system, facilitating faster signal transmission.
47
What are the protective membranes of the CNS from which brain tumors can arise?
Meninges
## Footnote
Meninges serve as protective layers covering the brain and spinal cord.
48
What is a source of brain tumors besides glial cells and meninges?
Metastasis from nonneuronal tumors in other organs
## Footnote
This refers to tumors that originate in other parts of the body and spread to the brain.
49
Which cells in the brain are known to be mitotically active throughout life?
Glial cells
## Footnote
Glial cells support and protect neurons in the CNS.
50
What are gliomas?
Tumors of glial cells that grow rapidly and are highly malignant
## Footnote
Gliomas can be aggressive and are often challenging to treat.
51
True or False: Gliomas are benign tumors.
False
## Footnote
Gliomas are characterized as highly malignant tumors.
52
Fill in the blank: Brain tumors arise from _______.
Meninges, metastasis from nonneuronal tumors, glial cells
## Footnote
This encompasses various origins of brain tumors.
53
What is depolarization in electrophysiology?
Voltage becomes less negative, more positive
54
What occurs during repolarization?
Voltage returns to its original negative value
55
What is hyperpolarization?
Voltage becomes more negative than RMP
56
Define local potential.
Local disturbances in membrane potential – Short range
57
What is the effect of an excitatory local potential?
Action potential is more likely to happen
58
What is the effect of an inhibitory local potential?
Action potential is less likely to happen
59
What is an action potential?
Dramatic, transient change in membrane potential that is propagated down the membrane
60
What is the resting membrane potential of a neuron?
-70 mV
## Footnote
This is the state when both Na+ and K+ voltage-gated channels are closed.
61
What occurs during the local potential stage of an action potential?
Slight influx of Na+
## Footnote
This initial change can lead towards reaching the threshold for an action potential.
62
At what membrane potential is the threshold met for an action potential?
-55 mV
## Footnote
This is the critical point where action potential is initiated.
63
What happens when the threshold of -55 mV is reached?
Na+ voltage-gated channels open
64
What is the peak membrane potential reached during depolarization?
+30 mV
65
What occurs at +30 mV during an action potential?
Na+ voltage-gated channels close
66
What happens to K+ voltage-gated channels during an action potential?
They open after Na+ channels close
67
What is the process of K+ leaving the cell called?
Repolarization
68
What stops the efflux of K+?
K+ voltage-gated channels close
69
What occurs during hyperpolarization?
Membrane potential becomes more negative than resting potential
70
How is the resting membrane potential restored after an action potential?
Through the Na+/K+ exchange pump
71
What is the absolute refractory period?
No stimulus of any strength will trigger a new action potential
## Footnote
This period occurs immediately after an action potential.
72
What is the relative refractory period?
A new action potential can only be triggered with a usually strong stimulus
## Footnote
This period follows the absolute refractory period.
73
At what threshold mV does the absolute refractory period occur?
+35 mV
## Footnote
This is the peak of the action potential.
74
At what threshold mV does the relative refractory period begin?
-55 mV
## Footnote
This threshold indicates the start of the relative refractory period.
75
What is the resting membrane potential in mV?
-70 mV
## Footnote
This is the typical resting state of a neuron.
76
Fill in the blank: The _______ period is when no stimulus can trigger a new action potential.
absolute refractory
77
Fill in the blank: The _______ period requires a usually strong stimulus to trigger a new action potential.
relative refractory
78
What are the two factors that affect signal conduction speed?
Diameter of fiber and presence of myelin
## Footnote
Larger diameters and myelination increase conduction speed.
79
How does fiber diameter affect signal conduction speed?
Larger fibers conduct signals faster
## Footnote
This is due to reduced resistance and increased surface area.
80
How does the presence of myelin affect signal conduction speed?
Myelinated fibers conduct signals faster
## Footnote
Myelin acts as an insulator, allowing for saltatory conduction.
81
What is the conduction speed of a thin, unmyelinated neuron?
1.0 m/sec
## Footnote
Unmyelinated fibers have slower conduction speeds due to continuous conduction.
82
What is the conduction speed of a thick, myelinated neuron?
100 m/sec
## Footnote
Myelination and larger diameter significantly enhance conduction speed.
83
What type of motor function is associated with visceral motor neurons?
Stomach
## Footnote
Visceral motor neurons control involuntary functions.
84
What type of motor function is associated with somatic motor neurons?
Skeletal muscle
## Footnote
Somatic motor neurons control voluntary muscle movements.
85
What is a synapse?
Meeting point of neuron and other cell
## Footnote
Synapses are critical for neuronal communication.
86
What type of synapse connects an axon to a dendrite?
Axodendritic synapse
## Footnote
This is the most common type of synapse.
87
What type of synapse connects an axon to a cell body?
Axosomatic synapse
## Footnote
This type can influence the neuron's overall activity.
88
What type of synapse connects one axon to another axon?
Axoaxonic synapse
## Footnote
This type can modulate neurotransmitter release.
89
What is an electrical synapse?
A synapse where adjacent cells are joined by gap junctions.
90
What type of cells commonly utilize electrical synapses?
Cardiac and smooth muscle cells, and some neurons.
91
How do ions move in electrical synapses?
Ions diffuse from cell to cell.
92
What is the speed of transmission in electrical synapses?
Quick transmission.
93
Do electrical synapses involve integration or decision making?
No integration or decision making.
94
What is a chemical synapse?
A junction where a presynaptic neuron releases neurotransmitters to a postsynaptic cell
## Footnote
Chemical synapses facilitate communication between neurons through neurotransmitters.
95
What are neurotransmitters?
Messenger molecules released by presynaptic neurons
## Footnote
Neurotransmitters play a crucial role in transmitting signals across synapses.
96
What types of effects can neurotransmitters have?
They can be excitatory or inhibitory
## Footnote
Excitatory neurotransmitters promote the firing of the postsynaptic neuron, while inhibitory neurotransmitters prevent it.
97
What is acetylcholine?
A neurotransmitter released in the neuromuscular junction, autonomic nervous system, and by some neurons in the CNS.
## Footnote
Acetylcholine plays a key role in muscle activation and various autonomic functions.
98
What type of receptor is the nicotinic receptor?
Ligand-gated ion channel.
## Footnote
Nicotinic receptors are found on all ANS postganglionic neurons and skeletal muscles.
99
Where are nicotinic receptors located?
On all ANS postganglionic neurons, on skeletal muscles, and regions of the brain.
## Footnote
These receptors facilitate rapid synaptic transmission.
100
What type of receptor is the muscarinic receptor?
G-protein coupled receptor.
## Footnote
Muscarinic receptors mediate slower responses compared to nicotinic receptors.
101
Where are muscarinic receptors located?
On cardiac and smooth muscle and glands.
## Footnote
These receptors are involved in various parasympathetic nervous system functions.
102
What initiates the process at the excitatory cholinergic synapse?
AP reaches the synaptic knob and opens voltage-gated Ca2+ channels
103
What triggers the exocytosis of synaptic vesicles in an excitatory cholinergic synapse?
Ca2+ influx
104
What neurotransmitter is released during the process at an excitatory cholinergic synapse?
Acetylcholine (ACh)
105
What happens to empty synaptic vesicles after releasing ACh?
They refill with ACh
106
What occurs when ACh diffuses across the synaptic cleft?
It binds to ligand-gated NT receptors
107
What ions are involved in the channel opening after ACh binds to its receptor?
Na+ influx and K+ efflux
108
What may start an action potential in the excitatory cholinergic synapse?
Na+ influx
109
What enzyme breaks down ACh after it has performed its function?
Acetylcholinesterase
110
What bacterium is associated with botulism toxin?
Clostridium botulinum
111
What is the effect of botulism toxin on acetylcholine release?
Prevents the release of acetylcholine
112
How does botulism toxin prevent acetylcholine release?
Cleavage of SNARE proteins
113
What type of paralysis is caused by botulism toxin?
Flaccid paralysis
114
What is a monoamine?
A biogenic amine neurotransmitter derived from amino acids
## Footnote
Monoamines include catecholamines, serotonin, and histamine.
115
What are catecholamines derived from?
Tyrosine
## Footnote
Catecholamines include dopamine, norepinephrine, and epinephrine.
116
Which amino acid is serotonin derived from?
L-tryptophan
## Footnote
Serotonin is a key monoamine neurotransmitter.
117
Histamine is derived from which amino acid?
Histidine
## Footnote
Histamine plays various roles in the body, including immune responses.
118
What is the role of norepinephrine in the brain?
General mental/behavioral arousal
## Footnote
Norepinephrine is released by the sympathetic nervous system.
119
What type of receptor does norepinephrine bind to?
Adrenergic receptor
## Footnote
Adrenergic receptors are G-Protein Coupled Receptors.
120
Name the two types of adrenergic receptors.
* Alpha-adrenergic receptor
* Beta-adrenergic receptor
## Footnote
Alpha receptors are found in smooth muscle and the brain, while beta receptors are found in cardiac muscle, smooth muscle, and the brain.
121
True or False: Adrenergic receptors can be stimulated by epinephrine.
True
## Footnote
Epinephrine and amphetamines can stimulate adrenergic receptors.
122
Fill in the blank: Norepinephrine is released by the _______.
sympathetic nervous system
## Footnote
This is a key part of the body's fight or flight response.
123
What is a monoamine?
A biogenic amine neurotransmitter derived from amino acids
## Footnote
Monoamines include catecholamines, serotonin, and histamine.
124
What are catecholamines derived from?
Tyrosine
## Footnote
Catecholamines include dopamine, norepinephrine, and epinephrine.
125
Which amino acid is serotonin derived from?
L-tryptophan
## Footnote
Serotonin is a key monoamine neurotransmitter.
126
Histamine is derived from which amino acid?
Histidine
## Footnote
Histamine plays various roles in the body, including immune responses.
127
What is the role of norepinephrine in the brain?
General mental/behavioral arousal
## Footnote
Norepinephrine is released by the sympathetic nervous system.
128
What type of receptor does norepinephrine bind to?
Adrenergic receptor
## Footnote
Adrenergic receptors are G-Protein Coupled Receptors.
129
Name the two types of adrenergic receptors.
* Alpha-adrenergic receptor
* Beta-adrenergic receptor
## Footnote
Alpha receptors are found in smooth muscle and the brain, while beta receptors are found in cardiac muscle, smooth muscle, and the brain.
130
True or False: Adrenergic receptors can be stimulated by epinephrine.
True
## Footnote
Epinephrine and amphetamines can stimulate adrenergic receptors.
131
Fill in the blank: Norepinephrine is released by the _______.
sympathetic nervous system
## Footnote
This is a key part of the body's fight or flight response.
132
What is the nigrostriatal dopamine system associated with?
Control and initiation of movements
## Footnote
It specifically involves the substantia nigra
133
What disease is caused by the degeneration of neurons in the nigrostriatal dopamine system?
Parkinson's disease
## Footnote
This condition affects movement due to lack of dopamine
134
What treatments are commonly used for Parkinson's disease?
L-dopa and MAOIs (monoamine oxidase inhibitors)
## Footnote
These treatments help increase dopamine levels
135
What is the role of the mesolimbic dopamine system?
Involved in emotional reward systems and addictions
## Footnote
Associated with substances like nicotine and alcohol
136
What mental health condition is linked to excess dopamine in the mesolimbic dopamine system?
Schizophrenia
## Footnote
This condition is characterized by altered perceptions and behavior
137
What type of drugs are used to treat schizophrenia?
Dopamine antagonists
## Footnote
These drugs help reduce the effects of dopamine
138
What is the major excitatory neurotransmitter in the brain?
Glutamate (glutamic acid)
## Footnote
It plays a critical role in brain function
139
What is the primary function of glutamate in the brain?
Constitutes the major energy use in the brain
## Footnote
It is essential for various brain activities
140
How do astrocytes interact with glutamate in the synaptic cleft?
They take glutamate to increase glucose uptake and blood flow
## Footnote
This process involves vasodilation
141
What type of receptors are glutamate receptors?
Ion channels
## Footnote
They allow ions to flow across the neuronal membrane
142
Which receptors work together in memory storage?
NMDA and AMPA receptors
## Footnote
They open channels that are blocked by Mg2+
143
What is GABA?
Gamma-aminobutyric acid, the most common neurotransmitter in the brain
## Footnote
GABA is used by 1/3 of the brain’s neurons.
144
What type of neurotransmitter is GABA?
Inhibitory
## Footnote
GABA opens Cl− channels when it binds to its receptor.
145
What role does GABA play in the brain?
Involved in motor control
## Footnote
GABA's activity is crucial for regulating muscle tone and movement.
146
What disease is associated with the degeneration of GABA-secreting neurons in the cerebellum?
Huntington’s disease
## Footnote
The loss of these neurons leads to motor control issues characteristic of the disease.
147
What happens during the cessation of neurotransmitter signaling?
Presynaptic cell stops releasing NT
## Footnote
This process is crucial for the end of neurotransmitter action.
148
How long does a neurotransmitter stay bound to its receptor?
About 1 ms
## Footnote
After this time, it is cleared from the receptor.
149
What are the methods by which neurotransmitters are cleared from the synaptic cleft?
Diffusion, absorption by astrocytes or satellite cells, reuptake, and degradation
## Footnote
Each method plays a role in regulating neurotransmitter levels.
150
What is reuptake in the context of neurotransmitter signaling?
Reuptake transporters absorb neurotransmitters back into the presynaptic neuron
## Footnote
This process helps recycle neurotransmitters for future use.
151
What enzyme is responsible for the degradation of acetylcholine?
Acetylcholinesterase (AChE)
## Footnote
AChE breaks down acetylcholine in the synaptic cleft, terminating its action.
152
What is spatial summation?
Input from multiple neurons
## Footnote
Spatial summation occurs when multiple presynaptic neurons collectively influence a postsynaptic neuron.
153
What is temporal summation?
Multiple inputs from a single neuron
## Footnote
Temporal summation happens when a single presynaptic neuron fires multiple times in quick succession.
154
What is synaptic plasticity?
The ability of the synapses to change in response to activity
## Footnote
Synaptic plasticity is a fundamental mechanism that underlies learning and memory.
155
What is long-term potentiation (LTP)?
Repeated stimulation enhances excitability
## Footnote
LTP is associated with strengthening synapses based on recent patterns of activity.
156
What is the role of AMPA glutamate receptors in LTP?
Insertion of AMPA glutamate receptors
## Footnote
The insertion of these receptors into the postsynaptic membrane increases synaptic strength.
157
What is long-term depression (LTD)?
Low frequency of stimulation
## Footnote
LTD is a process that weakens synaptic connections and is considered the opposite of LTP.
158
What happens to AMPA glutamate receptors during LTD?
Removal of AMPA glutamate receptors
## Footnote
This removal leads to a decrease in synaptic strength.
159
What does qualitative information depend on in neural coding?
Qualitative information depends on which neurons fire.
160
What is a labeled line code?
A neuron only carries one type of information.
161
What does quantitative information represent?
Information about the intensity of a stimulus.
