Exam 1 pt 2 Flashcards

1
Q

Which of the following evolutionary adaptations result in increasing the speed of
conduction of action potentials by decreasing the longitudinal resistance of the
axon?

A

Increasing the diameter of the axon

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2
Q

Which of the following events is associated with depolarization of a neuronal
membrane?

A

Flow of cations into the cell

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3
Q

During the depolarizing phase of the action potential, the voltage-gated Na+
channel is in which conformation?

A

Open/activated

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4
Q

Voltage-gated Na+ channels can be blocked by treating neurons with…

A

Tetrodotoxin (TTX)

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5
Q

During the absolute refractory period for a neuron, most voltage-gated Na+
channels are in which conformation?

A

Closed and not capable of opening

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6
Q

An action potential’s velocity depends upon…

A

Answers A and B are both correct (Membrane resistance, longitudinal resistance, magnitude of depolarization)

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7
Q

The axons with the fastest action potential velocities would have…

A

both A and B are correct (myelination and thick axon diameters)

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8
Q

If a membrane is at its Reversal Potential (Erev) then…

A

Its emf = 0

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9
Q

An inhibitory neurotransmitter may…

A

Answers A, B, and C are all correct (increase gk , allowing K+to leave cell, thereby hyperpolarizing it, . increase gCl , allowing Clto
enter cell, thereby hyperpolarizing it, inhibit Ca2+ channels, which are required for neurotransmitter release)

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10
Q

Which of the following proteins (or protein complexes) is required for the
FUSION (not docking) of synaptic vesicles with the plasma membrane?

A

Synaptotagmin

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11
Q

What is the primary neurotransmitter released by postganglionic cells of
vertebrate sympathetic neurons?

A

norepinephrine

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12
Q

Stimulus intensity, or strength, is encoded in…

A

frequency of action potentials with stronger stimuli eliciting higher
frequencies.

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13
Q

The purpose of acetylcholinesterase is to…

A

break down acetylcholine at synapses to limit its availability for
activating its receptor

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14
Q

When a single synaptic input fires repeatedly, generating a cumulative effect
on postsynaptic membrane potential, that phenomenon is known as…

A

temporal

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15
Q

Which of the following is (are) true regarding PEPTIDE neurotransmitters?

A

Both answers A and B are correct ( Many may act as neurotransmitters and as hormones, Some are released from multiple tissues, such as sensory neurons, autonomic neurons, CNS neurons, and intestinal endocrine cells)

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16
Q

What is the effect of heterosynaptic facilitation on SENSORY neurons?

A

action potential is prolonged

17
Q

Voltage-gated K+ channels can be blocked by treating neurons with

18
Q

Which part of a neuron has the highest density of voltage-gated Na+ channels?

A

the axon hillock

19
Q

What experiments did Galvoni conduct?

A

He crushed muscle and saw that the nerve was stimulated when unlike metals completed the circuit to stimulate uncrushed muscle.

20
Q

What does the intercellular electrode measure?

A

Action potential: if you inject neg current, it polarizes the cell. If you inject enough current you reach the threshold potential and cause a conformational change.

21
Q

Capacitors store ___

22
Q

What effect does more leak channels have on resistance?

A

It lowers resistance (shortens response)

23
Q

Nernst eq:

A

58*log([I]out/[I]in)

24
Q

What does the patch clamp technique do?

A

Helps understand channel density, refractory periods and single channels

25
Q

What effect to ion channels have on membrane capacitance?

A

They create resistance

26
Q

What is Tau?

A

The time it takes to reach 63% of the amplitude

27
Q

What is lambda?

A

The length to drop 63% of from the max. Show axial resistance

28
Q

What is needed for action potential to occur?

A

Open the voltage gated Na+ channels, open the K+ channels –> Na+ channels inactivate and K+ channels go back to resting. Action potential moves down the axon doing this

29
Q

What is the myelin sheath made of?

A

Glial cell membrane

30
Q

What is the effect of the myelin sheath?

A

Insulates. “Seperates the plates” to lower the capacitance, which means it does not have the neutralize the Na+, and can quickly jump to the next node

31
Q

Compounded action potential…

A

Distinct humps on a graph: groups alpha, beta and gamma add up. Some groups are fast (tall hump) while some are much slower (short hump)

32
Q

How does the vessicle containing neurotransmitter enter the synapse?

A

Ca2+ pulls the vessicle (binds to proteins that are docking it to the membrane) through.

33
Q

What vesicle proteins allow neurotransmitter to dock to the membrane?

A

Synapsin (re-docking), synaptotagnin (fusion)

34
Q

Action potential humps represent ____ vesicular events…

35
Q

What is the difference between stimulated and spontaneous vessicular events?

A

Stimulated = taller and has threshold

Spontaneous=shorter

36
Q

What is the quantal hypothesis?

A

Transmitters are released in packets (shown by studying spontaneous vesicular events using Ca blockers)

37
Q

What are metabitrophic receptors?

A

Open/close the channel when the transmitter binds