Exam # 3 Chapter 12 Flashcards
(155 cards)
1
Q
- consists of the brain and spinal cord
- processes many kinds of incoming sensory information
- the source of thoughts, emotions, and memories
- most signals that stimulate muscles to contract and glands to secrete originate here
A
central nervous system (CNS)
2
Q
- consists of all nervous tissue outside the CNS
- components are nerves and sensory receptors
A
peripheral nervous system (PNS)
3
Q
-bundles of hundreds to thousands of axons plus associated connective tissue and blood vessels that lies outside the brain and spinal cord
A
nerve
4
Q
- structure of the nervous system that monitors changes in external or internal environment
- Ex: touch, photo receptors in the eye, and olfactory receptors in the nose
A
sensory receptors
5
Q
-the PNS is divided into _____ and _____ divisions
A
sensory and motor
6
Q
- the _____ or afferent division of the PNS conveys input into CNS from sensory receptors
- provides the CNS with information about the ____ and _____ senses
A
sensory division
somatic and special senses
7
Q
-the _____ senses are tactile, thermal, pain and proprioceptive (where things are in space)
A
somatic
8
Q
-the _____ senses are smell, taste, vision, hearing, and equilibrium (balance,ph, pressure senses)
A
special
9
Q
- the _____ or efferent division of the PNS conveys output from the CNS to effectors (muscles and glands)
- its further divided into a somatic nervous system and autonomic nervous system
A
motor division
10
Q
- conveys output from the CNS to skeletal muscles only
- voluntary action
A
somatic nervous system (SNS)
11
Q
- conveys output from the CNS to smooth and cardiac muscles and glands
- involuntary action
A
autonomic nervous system (ANS)
12
Q
-the sympathetic, parasympathetic, and enteric nervous system are the main branches of the _____
A
autonomic nervous system
13
Q
-the ____ and ____ of the ANS consists of smooth and cardiac muscle and glands
A
sympathetic and parasympathetic nervous system
14
Q
-the _____ of the ANA consist of smooth muscle and glands of GI tract
A
enteric nervous system
15
Q
-the functions of the nervous system are:
- ____ detects internal and external stimuli
- _____ process info and make decisions
- _____ activate effectors and elicit a response
A
sensory function
integrative function * also known as integration
motor function
16
Q
- the ____ is always on
- the _____ responds to changes in environment
A
parasympathetic
sympathetic
17
Q
-are the receiving or input portions of a neuron, carry signal to cell body
A
dendrites
18
Q
-long, thin cylindrical projection that carry signals away
A
axons
19
Q
-prominent clusters of rough ER- materials produced here may be used to regenerate axons in the PNS
A
nissl bodies
20
Q
-cone shaped region where axon joins cell body, nerve impulses arise in the trigger zone
A
axon hillock
21
Q
-the cytoplasm and plasma membrane of axon
A
axoplasm
axolemma
22
Q
-bundles of intermediate fibers, provides the cell with shape and support
A
neurofibrils
23
Q
-the dendrites, cell body, and axon is the basic parts of a _____
A
neuron
24
Q
-neurons can be classified with 3 ways:
A
shape, size, and functions
25
- ______ neurons have several dendrites and one axon
- most neurons of CNS
- all motor neurons
multipolar neurons
26
- _____ neurons have one main dendrite and one axon
- retina in eye
- inner ear
- olfactory are of brain
bipolar neurons
27
- _____ neurons have dendrites and one axon that are fused together (pseudo-unipolar)
- sensory receptors
- cell bodies in ganglia
unipolar neurons
28
- have mossy fibers
- located in the cerebellum, these neurons redulate movement
- intricate series of connections
purkinje cell
29
- found in the pre-frontal cortex, the home of cognition
| - because many other axons can terminate on the dendrites, a single cell can have 30,000 excitatory inputs
pyramidal cell
30
- sensory neurons (afferent) are found in the ____
- interneuron are found in the _____
motor neurons (efferent) are found in the _____
PNS
CNS
PNS
31
- make up about half the volume of the CNS
| - the glue that holds nervous tissue together
neuroglia
32
-astrocytes, oligodendrocytes, microglial, and ependymal cells are cells of the _____ system
CNS
33
- star-shaped, largest and most numerous, many processes that contact neurons, blood capillaries, and pia mater
- contain microfilaments for support
- isolate neurons from harmful substances in blood (blood brain barrier)
- maintain chemical environment fro impulses
- growth, migration, formation of synapses (in embryo as well as learning/memory)
astrocytes
34
- like astrocytes but smaller, fewer processes
| - form the myelin sheath around CNS axons
oligodendrocytes
35
-small, spiny cells, that function like macrophages (remove debris, microbes)
microglial cells
36
- single layer of cuboidal/columnar cells
| - produce and assist in the circulation of cerebrospinal fluid
ependymal cells
37
-the cell bodies of most unipolar neurons are located in the _____,(collection on cell bodies) of spinal and cranial nerves
ganglia
38
- these cells are like oligodendrocytes, but myelinate a single axon or a parallel bundle
- participates in axon regeneration
schwann cells
39
- flat cell bodies of neurons or ganglia
| - support and regulate exchange of material with interstitial fluid
satellite cells
40
-the two types of cells in the PNS are _____ and _____
schwann cells
satellite cells
41
-axons surrounded by a multilayered lipid and protein covering called the _____
myelin sheath
42
-when a axon is _____, the sheath electrically insulates the axon of a neuron and increases the speed of the nerve impulse conduction
myelinated
43
-axons without a covering are said to be _____
unmyelinated
44
-the two types of neuroglia that produce myelin sheaths are _____ and _____
schwann cells
oligodendrocytes
45
- the outer nucleated cytoplasmic layer of the schwaan cell, which encloses the myelin sheath is the _____
- it is found only around axons in PNS
neurolemma
46
-cluster of neuronal cell bodies located in the PNS
ganglion
47
-_____ is composed primarily of myelinated axons
white matter
48
- _____ of the nervous system contains neuronal cell bodies, dendrites, unmyelinated axons, axon terminals, and neuroglia
- it appears grayish because the nissl bodies impart a gray color and there is no myelin in these areas
gray matter
49
-neurons are electrically excitable and communicate with one another using two types of electrical signals: the _____ and _____
graded potential
action potentials
50
-_____ potentials are used for short distance communication only
graded potential
51
-_____ potentials allow communication over long distances within the body
action potential
52
-an action potential in a muscle fiber is called a _____
muscle action potential
53
-an action potential that occurs in a neuron is called a _____
nerve action potential
54
-graded potentials and nerve and muscle action potentials are involved in the relay of sensory stimuli, integrative functions such as _____ and _____
perception
motor activities
55
- the pathway of _____
* receptor
* sensory neuron
* interneuron
* upper, lower motor neurons
* neuromuscular junction
electrical signals
56
-the electrical signals produced by neurons and muscle fibers rely on four types of ion channels the _____, the _____, the _____, and the _____
leak channels
ligand gated channel
mechanically gated channel
voltage gated channel
57
- gated channels that randomly open and close
- found in nearly all cells, including dendrites, cell bodies, and axons of all types of neurons
- passive process
leak channels
58
- gated channels that open in response to binding of ligand (chemical) stimulus
- dendrites of some sensory neurons such as pain receptors and dendrites and cell bodies of interneurons and motor neurons
- neurotransmitters, passive process
ligand gated channels
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- gated channels that open in response to mechanical stimulus such as touch, pressure, vibration, or tissue stretching
- dendrites of some sensory neurons such as touch receptors, pressure receptors, and some pain receptors
mechanically gated channels
60
- gated channels that open in response to voltage stimulus (change in membrane potential)
- axons of all types of neurons
voltage gated channels
61
- a anion has a _____ charge
| - a cation has a _____ charge
negative
positive
62
-an electrical potential difference (voltage) that exists across the plasma membrane of an excitable cell under resting conditions
resting membrane potential
63
Units for potential are in _____ and measures the difference in charge between the inside and outside
milivolts (mV)
64
-the _____ exists because of a small buildup of negative ions in the cytosol along the inside of the membrane, and the equal buildup of positive ions in the extracellular fluid along the outside surface of the membrane
resting membrane potential
65
- a cell the exhibits a membrane potential is said to be ____
- most body cells
polarized
66
- 3 factors that determine _____
* unequal amount of ions in the ECF and cytosol (more K+)
* inability of most anions to leave the cell
* the electrogenic nature of the Na+-K+ ATPases (3Na+ions out and 2 K+ions in)
resting membrane potential
67
-the ____ in the resting membrane potential return things back to keep exchanging ions
leak channels
68
- steps in the _____
* Na+ and Cl- and in the ECF
* K+ and phosphates, proteins in the cytosol
* the negative ions/molecules don't cross the membrane
* the movement of the positive ions (cations) out of a region cause it to become more negative
* typically -70mV
membrane potential
69
- occur in the dendrites
- vary in size
- can be hyperpolarizing or depolarizing
graded potential
70
- potential starts at -70, more polarized is increasingly negative
- trying to stop something
hyperpolarizing graded potential
71
- potential moves back towards zero, less negative
- easier for the body to do
- trying to start something
depolarizing graded potential
72
-_____ regions of the membrane naturally return to resting potential, so graded potentials are short term
depolarized
73
-successive depolarization can undergo _____, adding together to reach a new level
summation
74
-a _____ forms in response to the opening of mechanically gated channels or ligated channels
graded potential
75
-_____ or impulse is a sequence of rapidly occurring events that decrease and reverse the membrane potential and the eventually restore it to the resting state
action potential
76
-an action potential has two main phases the _____ and _____
depolarizing phase
repolarizing phase
77
-the negative membrane potential becomes less negative, reaches zero, and then becomes positive
depolarizing phase
78
-the membrane potential is restored to the resting state of -70mV
repolarizing phase
79
-after repolarizing phase, there may be a _____, which the membrane potential temporarily becomes more negative than the resting level
after-hyperpolarizing phase
80
-incoming signal strength does not increase the size of an _____ but the frequency
action potential (AP)
81
- an action potential occurs in the membrane of the axon of a neuron when depolarization reaches a certain level called the _____
- about -55mV
threshold
82
-an action potential will not occur in response to a _____, a weak depolarization that cannot bring the membrane potential to threshold
subthreshold stimulus
83
-an action potential will occur in response to a _____, a stimulus that is just strong enough to depolarize the membrane threshold
threshold stimulus
84
- multiple action potentials will form in response to a _____, a stimulus that is strong enough to depolarize the membrane above threshold
- each AP is the same size, the amplitude is always the same regardless of the stimulus intensity
suprathreshold stimulus
85
-active transport is the result of the _____
resting membrane potential
86
-the period of time after an AP begins during which as excitable cell cannot generate another AP in response to a normal threshold stimulus is called the _____
refractory period
87
-during the _____, even a very strong stimulus cannot initiate a second AP, the Na+ channels cannot reopen, they must return to the resting state
absolute refractory period
88
- the period of time which a second AP can be initiated, only by a larger than normal stimulus
- voltage gated K+ channels are still open after inactivated Na+ channels have returned to resting state
relative refractory period
89
- the ion flow through voltage gated channels during depolarizing and repolarizing phase of an _____ are:
* resting state
* depolarization phase
* repolarization phase begins
* repolarization phase continues
action potential
90
-all voltage gated Na+ and K+ channels are closed
resting state
91
-when membrane potential of axon reaches threshold the Na+channel activation gates open
depolarizing phase
92
- when Na+ channel inactivation gates close and K+ channels open
repolarizing phase begins
93
-when K+ outflow continues, K+ eventually restores resting membrane potential
repolarization phase continues
94
-there are two types of propagation in Ap's the _____ and _____
continuous conduction
saltatory conduction
95
- involves step by step depolarization and repolarization of each adjacent segment of plasma membrane
- AP propagates only a short distance
- occurs in unmyelinated axons and in muscle fibers
continuous conduction
96
- AP propagation that occur along myelinated axons
- occurs b/c of uneven distribution of voltage gated channels
- looks like it is jumping from one node to another
saltatory conduction
97
- _____ arise from dendrites and cell body
| - _____ arise from trigger zones and propagate along axon
GP
AP
98
- _____propagate and thus permit communication over longer distances
- _____ decremental (not propagated), permit communication over short distances
AP
GP
99
- _____ligid gated or mechanically gated ion channels
| - _____voltage gated channels for Na+ and K+
GP
AP
100
- _____all or none, typically about 100mV
| - _____depending on strength of stimulus, varied from less than 1mV to more than 50 mV
AP
GP
101
- _____typically longer, ranging from several milliseconds to several minutes
- _____shorter, ranging from 0.5 to 2 msec
GP
AP
102
- _____ always consist of depolarizing phase followed by repolarizing phase and return to resting phase
- _____may be hyperpolarizing (stopping AP), or depolarizing (exciting AP)
AP
GP
103
- _____if not present, summation can occur
| - _____ if present, summation cannot occur
GP
AP
104
-is the connection between an axon terminus of one neuron and another neuron or an effector
synapse
105
-nerve cell that carries nerve impulse towards synapse, the cell that sends the signal
presynaptic neuron
106
-a cell that receives a signal
postsynaptic cell
107
-nerve cell that carries nerve impulse away from a synapse
postsynaptic neuron
108
-responds to the impulse at the synapse
effector cell
109
- most synapse between neurons are _____
| - from axon to dendrite
axodendritic
110
-synapse from axon to cell body
axosomatic
111
-synapse from axon to axon
axoaxonic
112
-_____ neurons connects to _____ neurons or effector cells
presynaptic
postsynaptic
113
-two types of synapses are _____ and _____
gap junctions
chemical synapse
114
- contains tubular connexons, which acts like tunnels to connect cytosol to cells
- as ions flow from once cell to the next through connexons, the AP spreads from cell to cell
gap junctions
115
-NT's carry signal across the gap is a _____
chemical synapse
116
- time it takes to cross the synapse, virtually absent in gap junctions
- the reason that chemical synapses relay signals more slowly than electrical synapses
synaptic delay
117
- current is created by _____ crossing the cell membrane and changing the potential
- if you bridge the two _____, the current is allowed to travel from one cell to the next
ions
cytosols
118
-a _____ transmits a signal as follows:
* presynaptic neuron brings Gp or AP
* volt gated Ca2+ channels open
* Ca2+ induces exocytosis of NT's
* post synaptic channels bind NT's
* NT's cause Na+ channels to open
* influx of N causes post synaptic potential (PSP)
* nerve impulse is conducted away from synapse
chemical synapse
119
- which integral changes the signal from electrical to chemical ?
- from chemical to electrical ?
voltage gated Ca2 channels
ligand-gated
120
-the depolarizing phase of the nerve impulse opens _____, which are present in the membrane of synaptic end bulb
voltage gated Ca2+ channels
121
- as ions flow through the opened channels, the voltage across the membrane changes, this is a _____
- depending on which ions the channels admit, it may be depolarization (excitation) or hyperpolarization (inhibition)
postsynaptic potential
122
* these are simply changes in membrane potential
- a depolarizing (positive) postsynaptic potential is called _____, more like to cause an impulse, moving from resting (-70mV) towards threshold (-55mV)
- a hyperpolarizing (negative) postsynaptic potential is called _____, less likely to cause impulse
excitatory postsynaptic potential (EPSP)
inhibitory postsynaptic potential (IPSP)
123
- is type of NT receptor that contains a NT binding site and an ion channel
- the NT binding site and the ion channel are components of the same protein
ionotropic receptor
124
- a type of NT receptor that contains a NT binding site but lacks an ion channel as part of its structure
- is coupled to a separate ion channel by a type of membrane protein called a G protein
* there are 2 integral proteins, binding ACh activates the G protein, which in turn opens the channel allowing K+ to flow out of the cell
- is IPSP (positive moving in wrong direction)
metabotropic acetylcholine receptor
125
- when ACh binds 2 sites on channel, allows cations to flow, depolarizing the membrane, this is a _____ receptor
- is EPSP
iontropic acetylcholine receptor
126
- _____ opens Cl- channels
- the influx of anions hyperpolarizes the membrane, this is the _____ receptor
- is IPSP (positive moving in wrong direction)
GABA (gamma-aminobutyric acid)
ionotropic GABA receptor
127
-both the _____ and _____ receptors are ionotropic, binding their NT directly causes the movement of ions by opening the ion channel
ACh
GABA
128
-receptors need to clear the NT, they are removed in 3 ways _____, _____, and _____
diffusion
enzymatic degradation
uptake
129
-when a NT is not near its receptors, it cannot bind
diffusion
130
- certain NT's are inactivated through _____
| * ex: acetylcholinesterase
enzymatic degradation
131
- when NT's are transported back by neighboring neuroglia, _____
- when NT's are transported back by pre-synaptic neuron
uptake
re-uptake
132
-the presence of free Ca2+ in the pre-synaptic neuron means NT vesicles can more easily be exocytosed
facilitation
133
-lack of NT vesicles due to rapid signals and failure to re-uptake NT's
synaptic fatigue
134
-results from the buildup of NT released simultaneously by several presynaptic end bulbs
spatial summation
135
-results from buildup of NT released by a single presynaptic end bulb two or more times in rapid succession
temporal summation
136
-the sum of all the excitatory and inhibitory effects at any given time determines the effect on the postsynaptic neuron, which may respond in the following ways _____ and _____
EPSP and IPSP
137
-if the net summation of EPSP's and IPSP's is a depolarization that reaches threshold, then an _____ will occur at the trigger zone of a postsynaptic neuron
action potential
138
- EPSP > IPSP, but can not reach threshold, a new EPSP is genearated
- ESPS > IPSP, threshold, one or more impulses (AP) genearated
- IPSP > EPSP, new IPSP generated
* this is the 3 outcomes of _____
summation
139
- best studied NT, is released by many PNS neurons and by some CNS neurons
- is an excitatory NT at some synapses, such as neuromuscular junction
- inhibitory at metabotropic channels
acetycholine (ACh)
140
-an amino acid NT, has powerful excitatory effects
glutamate aspartate
141
- plays roles in arousal (awakening from deep sleep), dreaming, and regulating mood, a stimulatory process, _____
- a smaller number of neurons in the brain use _____, as a NT, stress response
*biogenic amines
norepinephrine (NE)
epinephrine
142
- brain neurons containing the NT _____, are active during emotional responses, addictive behaviors, and pleasurable experiences
- regulation of skeletal muscles
*biogenic amines
dopamine
143
- a NT involved with sensory perception, temperature regulation, control of mood, appetite, and the induction of sleep
* biogenic amines
serotonin
144
-substance P, endorphins, angiotensin II, and cholecystokinin (CKK) are all _____
neuropeptides
145
-found in sensory neurons, spinal cord pathways, and parts of the brain associated with pain, enhances perception of pain
substance P
146
- inhibit pain by blocking release of substance P
| - may have role in memory and learning, sexual activity, control of body temp, and mental illness
endorphins
147
- stimulates thirst, may regulate blood pressure in brain, can raise BP
- as a hormone, causes vasocontriction and promotes release of aldosterone, which increases rate of salt and water reabsorption by kidneys
angiotensin II
148
- found in the brain and small intestine, may regulate feeding as a "stop eating" signal
- as a hormone, regulates pancreatic enzyme secretion during digestion, and contraction of smooth muscle in GI tract
cholecystokinin
149
*diverging circuit
- a neuron terminating on a single post-synaptic neuron, is considered a _____
- if one nerve terminates on several post-synaptic cells, the signal _____
- this _____ the amplifies the signal, not in intensity but in reach
simple series circuit
diverges
amplifies
150
- a _____ is many-to-one instead of one-to-many
- allows for integration of many EPSP and IPSP's
- allows an effector to be stimulated by different regions of the brain
converging circuit
151
-_____ have branches that synapse with earlier neurons in the circuit
the signal could last seconds or hours, until turned off by inhibitory neurons
-like a positive feedback loop
*ex: breathing, coordinated muscle activities, waking up, short term memory
reverberating circuit
152
-_____ diverge from a single neuron, and run in parallel pathways of different lengths
- the length of time it takes to travel longer distances cause a _____, when the signals converge they arrive at different times
- this allows coordination of precision activities such as math calculations
parallel after-discharge circuits
153
- axon and myelin sheath degenerate, but neurolemma remains
- schwaan cells replicate to form regeneration tube to facilitate axon repair
- hard to regenerate w/o neurolemma
* most nerve damage happens in PNS
nerve regeneration
154
- nervous system exhibits _____, throughout your life
| - the capability to change based on experience
plasticity
155
_____ releases binding sites in muscles
calcium
