Which combination of axon features should lead an axon to communicate with downstream cells most slowly An axon that is 1 long 2 short 3 wide 4 thin 5 myelinated 6 nonmyelinated ID: 464728
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Slide1
0
Neurons, Synapses, and SignalingSlide2
Which combination of axon features should lead an axon to communicate with downstream cells most slowly? An axon that is
1. long.
2. short. 3. wide. 4. thin. 5. myelinated. 6. nonmyelinated.
1, 3, and 5
1, 3, and 6
1, 4, and 6
2, 3, and 5
2, 4, and 6Slide3
Which combination of axon features should lead an axon to communicate with downstream cells most slowly? An axon that is
1. long.
2. short. 3. wide. 4. thin. 5. myelinated. 6. nonmyelinated.
1, 3, and 5
1, 3, and 6
1, 4, and 6
2, 3, and 5
2, 4, and 6Slide4
In a typical motor neuron, what is the correct sequence in which these structures usually become involved in transmitting an electrical current?
1. cell body
2. axon 3. axon hillock 4. dendrites 5. synaptic terminals4, 1, 3, 2, 5
5, 4, 1, 3, 2
4, 3, 1, 2, 5
5, 4, 1, 2, 3
4, 1, 2, 3, 5Slide5
In a typical motor neuron, what is the correct sequence in which these structures usually become involved in transmitting an electrical current?
1. cell body
2. axon 3. axon hillock 4. dendrites 5. synaptic terminals4, 1, 3, 2, 5
5, 4, 1, 3, 2
4, 3, 1, 2, 5
5, 4, 1, 2, 3
4, 1, 2, 3, 5Slide6
Which gradient(s) is/are directly responsible for producing membrane potentials? 1. concentration gradient
2. pressure gradient
3. partial pressure gradient 4. electrical gradient1 only1 and 42 and 3
1, 3, and 4
all fourSlide7
Which gradient(s) is/are directly responsible for producing membrane potentials? 1. concentration gradient
2. pressure gradient
3. partial pressure gradient 4. electrical gradient1 only1 and 42 and 3
1, 3, and 4
all fourSlide8
How many of these statements about hyperpolarization of a neuron is/are true? When hyperpolarization occurs, 1. membrane potential is more negative than during resting potential.
2. membrane potential is closer to
EK than it is to ENa. 3. K
+
and/or
Cl
−
channels are open.
4. if it occurs in a downstream neuron, IPSPs are more likely to be generated than are EPSPs.
5. generation of action potentials is less likely to occur.
only one statement
two statements
three statements
four statements
all five statementsSlide9
How many of these statements about hyperpolarization of a neuron is/are true? When hyperpolarization occurs, 1. membrane potential is more negative than during resting potential.
2. membrane potential is closer to
EK than it is to ENa. 3. K
+
and/or
Cl
−
channels are open.
4. if it occurs in a downstream neuron, IPSPs are more likely to be generated than are EPSPs.
5. generation of action potentials is less likely to occur.
only one statement
two statements
three statements
four statements
all five statementsSlide10
Resting potential is mostly due to ion movements through which two of the following? 1. Na
+
/K+ pumps 2. voltage-gated Na+ and K+ channels 3. ligand-gated Na+ and K
+
channels
4. voltage-gated Ca
2
+
channels
5. Na
+
and K
+
leak channels
1 and 2
1 and 3
1 and 5
2 and 3
4 and 5Slide11
Resting potential is mostly due to ion movements through which two of the following? 1.
Na
+/K+ pumps 2. voltage-gated Na+ and K
+
channels
3. ligand-gated
Na
+
and
K
+
channels
4. voltage-gated
Ca
2
+
channels 5. Na+ and K+ leak channels
1 and 2
1 and 3
1 and 5
2 and 3
4 and 5Slide12
What is the correct sequence in which the following events occur, leading to the cessation of acetylcholine (ACh) stimulation of downstream skeletal muscle cells?
1. migration of synaptic vesicles ceases
2. ACh release from presynaptic membrane ceases 3. hydrolysis of last ACh molecules in synaptic cleft and postsynaptic membrane 4. removal of Ca2
+
from synaptic terminals
5. action potentials along motor neuron cease
1, 5, 4, 2, 3
5, 1, 4, 2, 3
4, 2, 3, 5, 1
4, 1, 2, 3, 5
5, 4, 1, 2, 3Slide13
What is the correct sequence in which the following events occur, leading to the cessation of acetylcholine (ACh) stimulation of downstream skeletal muscle cells?
1. migration of synaptic vesicles ceases
2. ACh release from presynaptic membrane ceases 3. hydrolysis of last ACh molecules in synaptic cleft and postsynaptic membrane 4. removal of Ca2
+
from synaptic terminals
5. action potentials along motor neuron cease
1, 5, 4, 2, 3
5, 1, 4, 2, 3
4, 2, 3, 5, 1
4, 1, 2, 3, 5
5, 4, 1, 2, 3Slide14
If an axon cannot perform
saltatory
conduction, then what is probably true of this axon?It has fewer voltage-gated Na+ channels than an axon that can perform saltatory conduction.
It lacks an effective myelin sheath.
It is associated with either Schwann cells or
oligodendrocytes
.
It has multiple nodes of Ranvier.
It generates fewer action potentials, and requires less ATP, than an axon of equal length that
can
perform
saltatory
conduction.Slide15
If an axon cannot perform
saltatory
conduction, then what is probably true of this axon?It has fewer voltage-gated Na+ channels than an axon that can perform saltatory conduction.
It lacks an effective myelin sheath.
It is associated with either Schwann cells or
oligodendrocytes
.
It has multiple nodes of Ranvier.
It generates fewer action potentials, and requires less ATP, than an axon of equal length that
can
perform
saltatory
conduction.Slide16
Which is most directly involved in causing neurotransmitter release from the presynaptic membrane?
Na
+K+Cl+Ca2
+
large,
proteinaceous
anionsSlide17
Which is most directly involved in causing neurotransmitter release from the presynaptic membrane?
Na
+K+Cl+Ca
2
+
large,
proteinaceous
anionsSlide18
If a single type of neurotransmitter, released simultaneously by many different neurons onto the same downstream neuron, causes far more K
+
channels than Na+ channels to open in this downstream neuron, then which of the following should occur as a result? 1. spatial summation 2. temporal summation 3. depolarization
4. hyperpolarization
5. IPSPs
6. EPSPs
1, 3, and 6
1, 4, and 5
1, 4, and 6
2, 4, and 6
2, 3, and 5Slide19
If a single type of neurotransmitter, released simultaneously by many different neurons onto the same downstream neuron, causes far more K
+
channels than Na+ channels to open in this downstream neuron, then which of the following should occur as a result? 1. spatial summation 2. temporal summation 3. depolarization
4. hyperpolarization
5. IPSPs
6. EPSPs
1, 3, and 6
1, 4, and 5
1, 4, and 6
2, 4, and 6
2, 3, and 5Slide20
a) acetylcholine—a biogenic
amine that affects sleep, mood, attention and
learningb) glutamate—an amino acid and the most common neurotransmitter in the CNSc) norepinephrine—an excitatory neurotransmitter synthesized from the amino acid tyrosine
d
) substance P—a
neuropeptide, excitatory neurotransmitter that mediates pain
perception
e
) nitric oxide—a
gaseous neurotransmitter that works like a
hormone
Which of the following neurotransmitters is incorrectly matched with its definition
?Slide21
a) acetylcholine—a biogenic
amine that affects sleep, mood, attention and
learningb) glutamate—an amino acid and the most common neurotransmitter in the CNSc) norepinephrine—an excitatory neurotransmitter synthesized from the amino acid tyrosine
d
) substance P—a
neuropeptide, excitatory neurotransmitter that mediates pain
perception
e
) nitric oxide—a
gaseous neurotransmitter that works like a
hormone
Which of the following neurotransmitters is incorrectly matched with its definition
?Slide22
Scientific Skills Exercises
The data from this experiment are expressed using scientific notation: a numerical factor times a power of 10. Remember that a negative power of 10 means a number less than 1. For example, the concentration 10
–1
M
(molar) can also be written as 0.1
M
.Slide23
a) 0.000000006
M
b) 0.00000002
M
c) 0.000006
M
d) 0.000009
M
What is the lowest concentration of morphine that blocked naloxone binding, in standard notation
?Slide24
a) 0.000000006
M
b) 0.00000002
M
c) 0.000006
M
d) 0.000009
M
What is the lowest concentration of morphine that blocked naloxone binding, in standard notation
?Slide25
no
effect at 0.0001
M
no
effect at 0.0004
M
c) no
effect at 0.001
M
d) no
effect at 10,000
M
What result did the researchers obtain for atropine, in standard notation
?Slide26
no
effect at 0.0001
M
no
effect at 0.0004
M
c) no
effect at 0.001
M
d) no
effect at 10,000
M
What result did the researchers obtain for atropine, in standard notation
?Slide27
Phenobarbital’s
concentration is 2,000 times higher
.
b) Phenobarbital’s concentration is 500 times higher.
c) Phenobarbital’s
concentration is 5,000 times higher.
d) Methadone’s
concentration
is 20,000
times higher.
Compare the concentrations for methadone
(
2
×
10
–8
M
) and phenobarbital (10
–4
M
). Which concentration is higher and by how much? Slide28
Phenobarbital’s
concentration is 2,000 times higher
.
b) Phenobarbital’s concentration is 500 times higher.
c) Phenobarbital’s
concentration is 5,000 times higher.
d) Methadone’s
concentration
is 20,000
times higher.
Compare the concentrations for methadone
(
2
×
10
–8
M
) and phenobarbital (10
–4
M
). Which concentration is higher and by how much? Slide29
a) morphine
, methadone, and serotonin only
b) morphine
, methadone, and
levorphanol
only
c) morphine
, methadone,
levorphanol
, phenobarbital, atropine, and serotonin
d) morphine
and methadone only
Which drugs blocked naloxone binding in this experiment? Slide30
a) morphine
, methadone, and serotonin only
b) morphine
, methadone, and
levorphanol
only
c) morphine
, methadone,
levorphanol
, phenobarbital, atropine, and serotonin
d) morphine
and methadone only
Which drugs blocked naloxone binding in this experiment? Slide31
a) All
of these drugs would have blocked naloxone binding at 10
–5
M
.
It
is impossible to tell from the data
.
c) None
of these drugs would have blocked naloxone binding at 10
–5
M
.
d) Phenobarbital
would have blocked naloxone binding at
10
–5
M
, but atropine and serotonin would not have.
Would phenobarbital, atropine, or serotonin have blocked naloxone binding at a concentration of 10
–5
M
?Slide32
a) All
of these drugs would have blocked naloxone binding at 10
–5
M
.
It
is impossible to tell from the data
.
c) None
of these drugs would have blocked naloxone binding at 10
–5
M
.
d) Phenobarbital
would have blocked naloxone binding at
10
–5
M
, but atropine and serotonin would not have.
Would phenobarbital, atropine, or serotonin have blocked naloxone binding at a concentration of 10
–5
M
?Slide33
a) They
are specific for the non-opiate drugs used in the experiment.
b) They
are specific for opiate drugs.
They
are specific for morphine.
d) They
are specific for both opiate and non-opiate drugs.
Morphine, methadone, and
levorphanol
blocked naloxone binding in this experiment. What do these results indicate about the brain receptors for naloxone
?Slide34
a) They
are specific for the non-opiate drugs used in the experiment.
b) They
are specific for opiate drugs.
They
are specific for morphine.
d) They
are specific for both opiate and non-opiate drugs.
Morphine, methadone, and
levorphanol
blocked naloxone binding in this experiment. What do these results indicate about the brain receptors for naloxone
?Slide35
a) There
are
no
opiate receptors in mammalian intestinal muscle tissue.
b) There
may be opiate receptors in mammalian intestinal muscle tissue. Further experiments are needed to be sure.
c) There
are opiate receptors in mammalian intestinal muscle tissue.
d) There
are no naloxone receptors in mammalian intestinal muscle tissue, but there are opiate receptors
.
When the researchers repeated the experiment using tissue from mammalian intestinal muscles rather than brains, they found no naloxone binding. What does this result suggest about opiate receptors in mammalian intestinal muscle tissue
?Slide36
a) There
are
no
opiate receptors in mammalian intestinal muscle tissue.
b) There
may be opiate receptors in mammalian intestinal muscle tissue. Further experiments are needed to be sure.
c) There
are opiate receptors in mammalian intestinal muscle tissue.
d) There
are no naloxone receptors in mammalian intestinal muscle tissue, but there are opiate receptors
.
When the researchers repeated the experiment using tissue from mammalian intestinal muscles rather than brains, they found no naloxone binding. What does this result suggest about opiate receptors in mammalian intestinal muscle tissue
?