Bbb Quiz 05

Front 1

Voltage-gated ion channels open:

a)In a dose-response fashion.
b)In an all or none fashion once a threshold is reached.
c)Only when the cell membrane is depolarized.
d)At resting potential.
e)Only when the cell membrane is hyperpolarized.

Back 1

b)In an all or none fashion once a threshold is reached.

Front 2

Na+ channels

a)Open more rapidly than K+ channels
b)Have a different time constant than K+ channels
c)May inactivate before the depolarization voltage returns to baseline
d)Open more slowly than K+ channels
e)a), b), and c)

Back 2

e)a), b), and c)

Front 3

The Thalamus

a)Is a main switching area in the brain, sending sensory information forward on to cortical areas.
b)Prevents sensory information from passing on to cortical areas during sleep.
c)Is the final destination for visual input.
d)Is the final destination for auditory input.
e)a) and b

Back 3

e)a) and b

Front 4

Which of the following reflects an accurate chain of events:

a)action potential--> voltage gated Ca+2 channels open--> vesicles migrate to and fuse with presynaptic cell membrane to release neurotransmitter

b)voltage gated Ca+2 channels open--> action potential--> vesicles migrate to and fuse with presynaptic cell membrane to release neurotransmitter

c)action potential--> vesicles filled with neurotransmitter are released--> voltage gated Ca+2 channels open

d)action potential--> voltage gated Na+ channels open--> vesicles migrate to and fuse with presynaptic cell membrane to release neurotransmitter

e)action potential--> voltage gated K+ channels open--> vesicles migrate to and fuse with presynaptic cell membrane to release neurotransmitter

Back 4

a)action potential--> voltage gated Ca+2 channels open--> vesicles migrate to and fuse with presynaptic cell membrane to release neurotransmitter

Front 5

Vesicles filled with neurotransmitters

a)migrate freely of their own will to the synaptic cleft.
b)are tethered to the cytoskeleton.
c)are set free from the cytoskeleton by Na+.
d)are set free from the cytoskeleton by Ca+2.
e)b) and d)

Back 5

e)b) and d)

Front 6

The shape of the action potential and underlying conductance changes can be calculated from the properties of which ion channels?

a) Cl- and K+
b) K+ and Ca+2
c) K+ and Na+
d) Na+ and Ca+2
e) Cl- and Ca+2

Back 6

c) K+ and Na+

Front 7

Which of the following is true of calcium ion channels?

a) Most nerve cells have only one type of calcium channel
b) Different types of calcium channel may have different voltage-gated properties
c) Different types of calcium channels may have different sensitivities to pharmacological blockers
d). The abbreviation for the ion passing through the calcium ion channel is Ca+
e). b and c only

Back 7

e). b and c only

Front 8

The ______________________ are a set of mathematical equations that model membrane conductance as a function of time and predict the dynamics of the membrane potential.

a) Goldman-Katz equations
b) Goldman-Sax equations
c) Schrödinger equations
d) Hodgkin-Huxley equations
e) Poisson equations

Back 8

d) Hodgkin-Huxley equations

Front 9

Which of the following is true regarding the difference between the absolute refractory period and the relative refractory period?

a) During the absolute refractory period no amount of depolarization will excite the cell but during the relative refractory period, with adequate stimulation, the cell may respond.

b) During the relative refractory period no amount of depolarization will excite the cell
but during the absolute refractory period, with adequate stimulation, the cell may respond.

c) During the absolute refractory period no amount of depolarization will excite the cell
but during the relative refractory period the cell responds relative to the fullness of the moon.

d) During the absolute refractory period no amount of depolarization will excite the cell but during the relative refractory period the cell will respond only when there is a full moon

e) None of the above

Back 9

a) During the absolute refractory period no amount of depolarization will excite the cell but during the relative refractory period, with adequate stimulation, the cell may respond.

Front 10

What is the neurotransmitter that opens ion channels in muscles?

a) 5-HTP
b) Dopamine
c) Serotonin
d) GABA
e) acetylcholine

Back 10

e) acetylcholine

Front 11

Human thermoregulation (e.g. sweating in a hot environment) is an
example of what type of regulatory mechanism?

a) positive feedback
b) feed-forward
c) feedback loop
d) control theory
e) negative feedback

Back 11

e) negative feedback

Front 12

During long-term depolarization, the _____ channels open slowly and
remain open longer than the ______ channels.

a) potassium/sodium
b) sodium/potassium
c) calcium/sodium
d) sodium/calcium
e) potassium/calcium

Back 12

a) potassium/sodium

Front 13

In most nerve cells the action potential is followed by a transient
hyperpolarization, termed the ________.

a) negative refractory period
b) absolute refractory period
c) after-potential
d) supra-polarization
e) late potential

Back 13

c) after-potential

Front 14

Which of the following modifies the total amount of neurotransmitter
release?

a) potassium influx
b) calcium efflux
c) sodium influx
d) potassium efflux
e) calcium influx

Back 14

e) calcium influx

Front 15

What is the process that describes the fusing of synaptic vesicles
with the pre-synaptic membrane and subsequent release of
neurotransmitters into the synaptic cleft?

a) endocytosis
b) endocytic cycling
c) vesicle docking
d) exocytosis
e) vesicle fusion

Back 15

d) exocytosis

Front 16

A contributing factor to synaptic plasticity is the regulation of
the concentration and flow of:

a) various ions
b) free calcium
c) neurotransmitters
d) potassium
e) sodium

Back 16

b) free calcium

Front 17

The Hodgkin-Huxley model for membrane conductance as a
function of time predicts __________.

a) membrane permeability
b) the dynamics of the membrane potential
c) the role of proteins
d) what type of ion channel will be activated
e) none of the above

Back 17

b) the dynamics of the membrane potential

Front 18

The leading edge of depolarization is generated by:

a) the opening of Na+ channels

b) the opening of K+ channels

c) the opening of Ca2+ channels

d) action potential

e) hyperpolarization

Back 18

a) the opening of Na+ channels

Front 19

Information flow between neurons is mediated by the
exchange of __________.

a) proteins
b) electrical impulses
c) K+
d) neurotransmitters
e) none of the above

Back 19

d) neurotransmitters

Front 20

Which of the following is true with regard to the dynamics of
sodium and potassium channels?

a) there are different time constants for K+ and Na+ channels
to open and close
b) Na+ channels open rapidly
c) K+ channels open slowly
d) all of the above
e) b & c only

Back 20

d) all of the above

Front 21

An ionotropic channel opens, permitting ions to flow through it, in response to:
a. the binding of a ligand to the receptor
b. a voltage change presynaptic cell
c. mechanical stimulation
d. ionotropic channels are not real
e. all of the above

Back 21

a. the binding of a ligand to the receptor

Front 22

The terminals of motor neurons form synapses with muscle fibers at specialized regions in the muscle membrane called:
a. muscle-plates
b. Schwarzenegger’s junction
c. end-plates
d. nodes of Ranvier
e. exit regions

Back 22

c. end-plates

Front 23

NMDA receptor-channels are considered unique because:
a. they contribute to mostly inhibitory signals
b. their opening depends on both chemical binding and membrane voltage
c. they are strictly ligand-gated
d. they are specialized receptors for area V5
e. they do not have the same initials as the National Miniature Donkey Asssociation (NMDA)

Back 23

b. their opening depends on both chemical binding and membrane voltage

Front 24

The final summing of all excitatory and inhibitory inputs is very important. This process happens at the:
a. the axon hillock
b. the nodes of Ranvier
c. the myelin sheaths
d. the synaptic cleft
e. the pre-synaptic cell

Back 24

a. the axon hillock

Front 25

The most common inhibitory neurotransmitters in the central nervous system are:
a. GABA
b. glycine
c. hydrogen chloride
d. sodium hydroxide
e. Both A and B

Back 25

e. Both A and B