Neural Tissue Flashcards
1
Q
employs electrical and chemical means to send messages from cell to cell.
A
Nervous system
2
Q
Nervous system carries out its task in three basic steps
A
receive information
processes this information
issues commands
3
Q
what are the subdivisons of the nervous system
A
central nervous system
peripheral nervous system
4
Q
what organs make up the central nervous system (CNS)
A
brain
spinal cord
5
Q
what are the subdivisions of the peripheral nervous system
A
sensory divison
motor divison
6
Q
what does the sensory division do?
A
carries signals from receptors to CNS
7
Q
what are the subdivisions of the sensory division
A
Visceral sensory division
Somatic sensory division
Special senses
8
Q
what does the Visceral sensory division do?
A
carries signals from the viscera (heart, lungs, stomach, and urinary bladder)
9
Q
what does somatic sensory division do?
A
carries signals from receptors in the skin, muscles, bones, and joints
10
Q
what are the special senses
A
smell
vision
hearing
taste
balance
11
Q
what are the subdivisions of the motor division
A
Visceral motor division
Somatic motor division
12
Q
what does motor division do
A
carries signals from CNS to effectors (glands and muscles that carry out the body’s response).
13
Q
what does Somatic motor division do?
A
carries signals to skeletal muscles leading to muscular contraction and somatic reflexes (involuntary muscle contractions).
14
Q
what does visceral motor division do?
A
carries signals to glands, cardiac and smooth muscle. Its involuntary responses are visceral reflexes.
15
Q
what is another name for visceral motor division
A
autonomic nervous system
16
Q
what are the subdivisions of the visceral motor division
A
Sympathetic division
Parasympathetic division
17
Q
what is the responsibility of the Sympathetic division
A
is responsible for the fight or flight response. It tends to arouse the body for action. It increases the heart rate, heart contractility, respiratory rate, but inhibits digestive and urinary systems.
18
Q
what is the responsibility of the Parasympathetic division
A
is responsible for the rest and digest response. It slows heart rate, breathing but stimulates digestive and urinary systems.
19
Q
What makes up the Peripheral nervous system (PNS)
A
the entire nervous system except the brain and spinal cord
(nerves and ganglia)
20
Q
a bundle of nerve fibers (axons) wrapped in fibrous connective tissue
A
Nerve
21
Q
a knot-like swelling in a nerve where neuron cell bodies are concentrated
A
Ganglion
22
Q
carries signals from receptors to CNS
A
Sensory (afferent) division
23
Q
what are the two components of the autonomic nervous system
A
Sympathetic nervous system
Parasympathetic nervous system
24
Q
what are the cells of the nervous tissue
A
neurons
neuroglia
25
cells used for communication by the nervous tissue
Neurons
26
Supporting cells of the nervous tissue
Neuroglia
27
what are the three classes of neurons
Sensory neurons
Interneurons
Motor neurons
28
Detect stimuli and transmit information about them toward the CNS
Sensory neurons
29
Receive signals from many neurons, integrates, processes and determines the appropriate response. Lie entirely within CNS connecting motor and sensory pathways (about 90% of all neurons).
Interneurons
30
Send signals out to muscles and gland cells (the effectors).
Motor (efferent) neurons
31
contains the nucleus and other structures common to living cells
soma
32
Multiple branches that come off the soma responsible for receiving signals from other neurons
Dendrites
33
the elongated portion of the neuron located in the center of the cell between the soma and terminals
axon
34
the region of a neuron that controls the initiation of an electrical impulse based on the inputs from other neurons or the environment
axon hillock
35
swellings that form contact points (synapses) with other cell, contains synaptic vesicles full of neurotransmitter
Axon terminals
36
what are the different structural classification of a neuron
Multipolar neuron
Bipolar neuron
Unipolar neuron
Anaxonic neuron
37
Multiple processes come out of the cell body usually one axon and multiple dendrites.
Multipolar neuron
38
examples of multipolar neurons
Most neurons in CNS.
39
Two processes come out of the cell body of the neuron usually one axon and one dendrite.
Bipolar neuron
40
examples of Bipolar neuron
Olfactory cells
retina
inner ear
41
Single process leading away from soma
Unipolar neuron
42
examples of Unipolar neuron
Sensory cells from skin and organs to spinal cord.
43
Many dendrites extend out of the cell body but no axon
Anaxonic neuron
44
examples of Anaxonic neuron
Retina
brain
adrenal gland
45
Many proteins and peptides made in the soma must be transported to the axon and terminal.
Axonal Transport
46
types of axonal transport
Anterograde transport
Retrograde transport
47
down the axon away from soma
Anterograde transport
48
up the axon toward the soma
Retrograde transport
49
what motor protein does anterograde transport use?
Kinesin
50
what motor protein does retrograde transport use?
Dynein
51
what are the neuroglia of the central nervous system (CNS)
Ependymal cells
Astrocytes
Microglia
Oligodendrocyte
52
Cuboidal epithelium with cilia on apical surface that line internal cavities of the brain. They secrete and circulate cerebrospinal fluid (CSF).
Ependymal cells
53
Most abundant glia in CNS. Star shaped cells that cover brain surface and most non synaptic regions of neurons.
Astrocytes
54
Macrophages that develop from white blood cells (monocytes) and become concentrated in areas of damage.
Microglia
55
Octopus like cells with arm-like processes that wrap around nerve fibers forming myelin sheaths in CNS that speed signal conduction.
Oligodendrocytes
56
what are the neuroglia of the peripheral nervous system
Schwann cells
Satellite cells
57
Wind around the axon and form myelin sheaths. Assist in regeneration of damaged fibers.
Schwann cells
58
Surround the somas of PNS neurons inside ganglia. They provide electrical insulation and regulate the chemical environment.
Satellite cells
59
Consists of the plasma membrane of glial cells, made up of 20% protein and 80% lipid.
myelin
60
what are the function of myelin
Provides insulation around the axon and increases action potential conduction velocity.
61
what is the myelin formed by in the CNS
Oligodendrocytes
62
what is the myelin formed by in the PNS
Schwann cells
63
label this
64
gaps between segments
Nodes of Ranvier
65
myelin-covered segments
Internodes
66
bare section of axon between the axon hillock and the first glial cell.
Initial segment
67
axon hillock and initial segment which plays an important role in initiating a nerve signal.
Trigger zone
68
what are the diseases of the Myelin Sheath
Multiple sclerosis
Tay sachs
69
Deterioration of Oligodendrocytes and myelin sheaths in CNS. Myelin replaced by hardened scar tissue which disrupts neve conduction. Cause may be autoimmune triggered by virus.
Multiple sclerosis
70
what are the symptoms of Multiple sclerosis
double vision, tremors, numbness, speech defects.
71
Hereditary disorder seen mainly in infants of Eastern European Jewish ancestry which is usually fatal before age 4. Abnormal accumulation of glycolipid called GM2 in the myelin sheath which disrupts conduction of nerve signals.
Tay–Sachs disease
72
what are the symptoms of Tay–Sachs disease
blindness, loss of coordination, dementia
73
what are the factors that can affect the speed of conduction
Diameter of the fiber
Presence of myelin
74
how does the diameter affect conduction
Larger axons have more surface area and conduct signals more
rapidly.
75
how does the Presence or absence of myelin Presence or absence of myelin
Myelin speeds signal conduction. Many neurons have unmyelinated axons and they have slower signal conduction compared to myelinated axons.
76
how are PNS nerve fibers regenerated
1. Axon distal to the injury degenerates and
macrophages clean up tissue debris.
2. Neurosoma swells, ER breaks up, and nucleus
moves off center due to the loss of nerve
growth factors from neuron’s target cell.
3. Axon stump sprouts multiple growth processes
4. Schwann cells, basal lamina, neurilemma form
regeneration tube which guides regrowth to
original destination
5. Once contact is reestablished with original
target, the neurosoma shrinks and returns to its
original appearance, nucleus returns to normal
shape and atrophied muscle fibers regrow.
77
how are CNS nerve fibers regenerated
usually unable to regenerate.
78
what is the resting membrane potential of neurons
-70 mV
79
how is the resting membrane potential of neurons made
Caused by separation of charge (ions) across the cell membrane with the inside of membrane negative relative to outside
80
- Moves 3 Na+ out of the cell and brings 2 K+ into
the cell using 1 ATP
- Helps create and maintain the sodium and
potassium ion concentration gradients across the
membrane.
Na+/K+ pump
81
At normal resting membrane potential, an electrical gradient opposes the chemical gradient for potassium ions (K+). The net electrochemical gradient tends to force potassium ions out of the cell.
Potassium Ion Gradients
82
At the normal resting membrane potential, chemical and electrical gradients combine to drive sodium ions (Na+) into the cell.
Sodium Ion Gradients
83
Change in membrane potential at and nearby point of stimulation may be a depolarization or a hyperpolarization.
Local potential
84
Rapid up-and-down shift in membrane potential that can travel a long distance down an axon. Always a rapid depolarization followed by repolarization and hyperpolarization.
Action potential
85
Two types of change in membrane potential:
Local potential
Action potential
86
shift in the voltage across the membrane to a less negative value
Depolarization
87
shift in the voltage across the membrane to a more negative value.
Hyperpolarization
88
label this
89
Period of resistance to stimulation during an action potential and for a few milliseconds after when it is difficult or impossible to initiate another action potential.
Refractory period
90
what are the Refractory period two phases
relative refractory period
absolute refractory period.
91
A stronger stimulus than usual is needed to trigger a new AP. During hyperpolarization, a larger depolarization (local potential) is required to reach threshold for another action potential to be triggered
relative refractory period
92
No stimulus of any strength will trigger another action potential due to inactivation of voltage-gated Na+ channels.
absolute refractory period.
93
occurs in unmyelinated axons that have voltage-gated channels along their entire length.
continuous propagation
94
in myelinated axons where electrical signal seems to jump from node to node. Moves faster through “insulated” segments covered with myelin and slows down when it reaches the bare axon of the nodes.
saltatory propagation
95
does saltatory propagation happen in myelinated axons or unmyelinated axons
myelinated axons
96
does continuous propagation happen in myelinated axons or unmyelinated axons
unmyelinated axons
97
a small gap at the end of a neuron that allows a signal to pass from one neuron to the next.
Synapses
98
which releases neurotransmitter and transmits the signal toward a synapse
Presynaptic neuron
99
responds to neurotransmitter
postsynaptic neuron
100
- Axon terminal of presynaptic neuron contains
synaptic vesicles containing neurotransmitter.
- Postsynaptic neuron membrane contains
neurotransmitter receptors. The neurotransmitter
receptors are ligand-gated ion gates that open
when neurotransmitters bind to them.
chemical synapse
101
four major chemical categories for neurotransmitters
Acetylcholine
Amino acids
Monoamines
Neuropeptides
102
what is the function of Acetylcholine
role in memory, learning, attention, arousal and involuntary muscle movement.
103
what is the function of Amino acids
are the main inhibitory and excitatory messengers in the nervous system
104
what are examples of Amino acids
glycine
glutamate
aspartate,
y-aminobutyric acid (GABA).
105
what is the function of Monoamines
modulation of psychomotor function, cardiovascular, respiratory and gastrointestinal control, sleep mechanisms, hormone secretion, body temperature, and pain.
106
what are examples of Monoamines
epinephrine, norepinephrine, dopamine, histamine, and serotonin
107
what is the function of neuropeptides
can modulate (increase or decrease) a postsynaptic response to a neurotransmitter
108
what are examples of neuropeptides
enkephalin
cholecystokinin
substance P
B-endorphins
109
what are the three kinds of synapses
* Excitatory cholinergic synapse
* Inhibitory GABA-ergic synapse
* Excitatory adrenergic synapse
110
a miniature transducer that converts a presynaptic electrical signal into a chemical signal (acetylcholine), which diffuses across the synaptic cleft, where it triggers another electrical signal on the postsynaptic side by interacting with acetylcholine receptors
Excitatory cholinergic synapse
110
balances glutamatergic excitatory drive and thereby controls neuronal output
Inhibitory GABA-ergic synapse
111
uses the monoamine neurotransmitter norepinephrine (NE) also called noradrenaline.
Excitatory adrenergic synapse
112
what are the events that lead to the cessation of the signal
Degradation
Reuptake
Diffusion
113
how does the cessation of the signal occur
Presynaptic cell stops releasing neurotransmitter
114
Enzyme in synaptic cleft breaks down neurotransmitter
Degradation
115
Neurotransmitter (or its breakdown products) reabsorbed into axon terminal
Reuptake
116
Neurotransmitter (or its breakdown products) simply diffuse away from synapse into nearby ECF
Diffusion
117
are chemicals secreted by neurons that have long term modulatory effects on groups of neurons
Neuromodulators
118
- is a simple neuromodulator
- Gas that enters postsynaptic cells and
activates second messenger pathways
Nitric oxide (NO)
119
are chains of amino acids that can act as neuromodulators
Neuropeptides
120
are neuropeptides that inhibit pain signals in the CNS.
Enkephalins
121
is the ability to process, store, and recall information and use it to make decisions.
Neural integration
122
is a voltage change from Resting membrane potential towards threshold and usually results from Na+ flowing into the cell
Excitatory Postsynaptic Potential (EPSP)
123
occurs when the cell's voltage becomes more negative than it is at rest
Inhibitory Postsynaptic Potential (IPSP)
124
is the process of adding up postsynaptic potentials and responding to their net effect which occurs in the trigger zone.
Summation
125
what are the two types of Summation
Temporal summation
Spatial summation
126
Occurs when a single synapse generates EPSPs so quickly that each is generated before the previous one fades. Allows EPSPs to add up over time to a threshold voltage that triggers an action potential.
Temporal summation
127
Occurs when EPSPs from several different synapses add up to threshold at an axon hillock. Simultaneous input from multiple presynaptic neurons are required for the postsynaptic neuron to fire.
Spatial summation
128
occurs when one presynaptic neuron enhances another one
Presynaptic facilitation
129
occurs when one presynaptic neuron suppresses another one
Presynaptic inhibition
130
ability of synapses to change
Synaptic plasticity
131
process of making transmission easier
Synaptic potentiation
132
what are the different types of memory
immediate memory
short-term memory
long-term memory
133
ability to hold something in your thoughts for a few seconds which is essential for reading ability. Allows for the ability to feel for the flow of events (sense of the present).
Immediate memory
134
lasts from seconds to a few hours. Includes working memory for taking action.
Short-term memory (STM)
135
may last a lifetime and can hold more information than short term memory.
Long term memory (LTM)
136
what are two types of long-term memory
explicit
implicit
137
memories you can put into words
Explicit
138
reflexive or unconscious memory. Includes procedural (motor skill) and emotional memories.
Implicit
139
symptoms of Alzheimer Disease
- Memory loss for recent events
- Moody, combative
- Loss of ability to talk, walk, and eat
140
symptoms of Parkinson Disease
- Progressive loss of motor function
- Degeneration of dopamine-releasing
neurons
- Dopamine normally prevents
excessive activity in motor centers
- Involuntary muscle contractions
