Exam 1 pt 2 Flashcards
(37 cards)
Which of the following evolutionary adaptations result in increasing the speed of
conduction of action potentials by decreasing the longitudinal resistance of the
axon?
Increasing the diameter of the axon
Which of the following events is associated with depolarization of a neuronal
membrane?
Flow of cations into the cell
During the depolarizing phase of the action potential, the voltage-gated Na+
channel is in which conformation?
Open/activated
Voltage-gated Na+ channels can be blocked by treating neurons with…
Tetrodotoxin (TTX)
During the absolute refractory period for a neuron, most voltage-gated Na+
channels are in which conformation?
Closed and not capable of opening
An action potential’s velocity depends upon…
Answers A and B are both correct (Membrane resistance, longitudinal resistance, magnitude of depolarization)
The axons with the fastest action potential velocities would have…
both A and B are correct (myelination and thick axon diameters)
If a membrane is at its Reversal Potential (Erev) then…
Its emf = 0
An inhibitory neurotransmitter may…
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)
Which of the following proteins (or protein complexes) is required for the
FUSION (not docking) of synaptic vesicles with the plasma membrane?
Synaptotagmin
What is the primary neurotransmitter released by postganglionic cells of
vertebrate sympathetic neurons?
norepinephrine
Stimulus intensity, or strength, is encoded in…
frequency of action potentials with stronger stimuli eliciting higher
frequencies.
The purpose of acetylcholinesterase is to…
break down acetylcholine at synapses to limit its availability for
activating its receptor
When a single synaptic input fires repeatedly, generating a cumulative effect
on postsynaptic membrane potential, that phenomenon is known as…
temporal
Which of the following is (are) true regarding PEPTIDE neurotransmitters?
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)
What is the effect of heterosynaptic facilitation on SENSORY neurons?
action potential is prolonged
Voltage-gated K+ channels can be blocked by treating neurons with
TEA
Which part of a neuron has the highest density of voltage-gated Na+ channels?
the axon hillock
What experiments did Galvoni conduct?
He crushed muscle and saw that the nerve was stimulated when unlike metals completed the circuit to stimulate uncrushed muscle.
What does the intercellular electrode measure?
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.
Capacitors store ___
charge
What effect does more leak channels have on resistance?
It lowers resistance (shortens response)
Nernst eq:
58*log([I]out/[I]in)
What does the patch clamp technique do?
Helps understand channel density, refractory periods and single channels
