Week 1 - Quiz Flashcards
At which region of a neuron does signaling change from graded potentials to action potentials?
Axon Hillock
What ions(s) is or are involved in EPSPs?
Both Na+ influx and K+ efflux, but sodium movement is much greater.
What type of channel will NOT be part of our initial studies of basic action potentials BUT is involved in the sensation of sound?
Mechanically gated channels.
What statement does NOT apply to the process of releasing neurotransmitters?
a. Vesicles use exocytosis to release neurotransmitter.
b. Neurotransmitters are released from the dendrites.
c. Neurotransmitters are specific to the synapse (meaning that we have more than one type in the nervous system).
d. The action potential allows voltage sensitive calcium channels at the axon terminal
B. Neurotransmitters are released from the dendrites.
Neurons that carry impulses to glands or muscles are called?
Efferent Neurons
What period of an action potential refers to when no added stimulus could cause another action potential to occur because the neuron is
currently involved in sending an action potential?
Absolute Refractory Period
Voltage-sensitive channels on a neuron respond to which stimuli?
a. Depolarization associated with the initial stimulus OR the action potential itself.
b. Neurotransmitter binding to these channels.
A.
What cell type insulates axons in the central nervous system?
Oligodendrocytes.
What type of signal in a neuron is ‘all or none’?
Action Potentials
Which cell type aids motion of the cerebrospinal fluid?
Ependymal cells.
What is a subthreshold depolarization?
A stimulus that causes depolarization, but never reaches -55 mV (e.g., -57 is maximum reached).
Do action potentials rely on summation? Meaning, must summation occur first in order to cause an action potential.
Yes
How do we code for the variation of intensity of stimuli in the nervous system? (e.g., strong smells versus faint smells).
We send more frequent or less frequent action potentials close together in time.
The site of graded potential conduction would be where on a neuron?
Dendrites AND cell bodies.
What feature is associated with the postsynaptic membrane? This week’s homework will help with this question.
a. Location where exocytosis is involved.
b. Location that releases neurotransmitters.
c. Location of receptors for neurotransmitters.
d. Location where calcium ions enter.
e. Also referred to as the presynaptic neuron.
C
What form of summation occurs when a single presynaptic neuron signals the postsynaptic neuron repeatedly in rapid succession?
Temporal Summation
What structure of the neuron allows conduction of an action potential that will eventually lead to release of neurotransmitter?
Axon
Chemically gated channels are found where on the neuron.
Dendrites
The fatty sheath surrounding some nerve fibers is called.
Myelin
What is a normal threshold for a neuron?
-55mV
The cation with high concentration outside of cells that is important to initiating an action potential is…
Sodium
Neurons that carry impulses toward the central nervous system (CNS) are called?
Afferent Neurons
Nodes of Ranvier are found where on the neuron.
Axons of myelinated neurons.
What structure maintains OR resets resting membrane potential after an action potential?
Na+/K+ pump.
Consider a scenario where two separate presynaptic neurons innervate a postsynaptic neuron. If the two presynaptic neurons fire at the
exact same time and intensity, but one sends an IPSP and the other sends an EPSP what is likely to happen in the postsynaptic neuron?
a. The EPSP will dominate, and the postsynaptic neuron will be excited.
b. The incoming IPSP and EPSP will cancel each other out (spatial summation) and the postsynaptic neuron will not send an
action potential.
c. The IPSP will dominate, and the postsynaptic neuron will be inhibited.
B
Graded potentials come in two forms. Which form is associated with depolarization of the neuron?
EPSPs
If a neuron experiences EPSPs does that mean the neuron will send action potentials?
It depends upon whether threshold is reached at the axon hillock.
Nodes of Ranvier would be associated with what pattern of action potential conduction.
a. Continuous conduction.
b. Saltatory conduction.
B. saltatory conduction
Identify the true statement regarding the autonomic nervous system (ANS).
a. It is part (a branch of) the central nervous system.
b. It is an afferent branch (meaning sensory) of the peripheral nervous system.
c. It is one branch of the efferent nervous system (meaning motor).
d. None of the listed options is correct.
e. It is also known as the Somatic nervous system.
C
What cell type provides most of the structural support for the CNS and helps create the blood brain barrier?
Astrocytes
Which cell type is NOT a neuroglial cell?
a. Neurons.
b. Schwann cells.
c. Oligodendrocytes.
d. Ependymal cells.
e. Astrocytes.
a. Neuron
What cell type has a neurilemma?
a. Astrocytes.
b. Neurons.
c. Ependymal cells.
d. Schwann cells.
e. Oligodendrocytes.
d. Schwann cells
Saltatory conduction occurs where on a neuron?
a. Myelinated neurons.
b. Synapse.
c. Dendrites.
d. Unmyelinated neurons.
e. Cell body.
a. Myelinated Neurons
What ion(s) is or are involved in IPSPs?
a. Cl- influx.
b. Na+ influx.
c. K+ efflux.
d. K+ efflux OR Cl- influx.
e. K+ efflux and Na+ influx.
D
The component of the neuron that facilitates ‘integration’ or the processing of incoming signals is?’
Cell Body
What neuron diameter will lead to faster conduction velocity for an action potential?
a. 1 to 5 micrometers.
b. Diameter of the axon does not impact conduction velocity.
c. 0.2 to 1.5 micrometers.
d. 13 to 28 micrometers.
e. 6 to 12 micrometers.
D
Which cell type CANNOT be part of the central nervous system (CNS)?
a. Oligodendrocytes.
b. Astrocytes.
c. Schwann cells.
d. Neurons.
e. Ependymal cells.
c. Schwann cells
When one presynaptic neuron innervates multiple postsynaptic neurons what type of circuit is this?
a. Integration circuit.
b. Diverging circuit.
c. Reciprocal inhibitory circuit.
d. Converging circuit.
b. Diverging circuit.
Consider the events of an action potential (imagine the graph to help you). What option would be the last to occur?
a. Hyperpolarization occurs.
b. Depolarization occurs.
c. Stimulus occurs.
d. Sodium channels open.
e. Potassium channels open.
a. Hyperpolarization occurs.
What type of neuron signal becomes weaker the farther it travels?
a. Graded potentials.
b. Action potentials.
a. Graded potentials.
Do you find mitochondria in the region of the axon terminals of neurons?
yes
Relative refractory period would correspond best to which aspect of an action potential?
a. The time between the stimulus and initiation of the depolarization phase.
b. The later portion of repolarization and hyperpolarization when the action potential is mostly accomplished.
c. The time when fast sodium channels close.
d. Only after hyperpolarization ends and resting membrane potential is completely restored.
b. The later portion of repolarization and hyperpolarization when the action potential is mostly accomplished.
