WorksheetsCell Neuro SI Exam 1 Review F24
Total questions: 27
Worksheet time: 14mins
The all-or-none principle of nerve action states that
the entire length of the nerve conducts an action potential or no part does.
an action potential always reaches its maximum strength or it doesn't appear at all.
all available ions contribute to the rise and fall of the action potential or none do.
all synapses on a neuron must be active in order for them to excite it.
The rapid depolarization of an axonal membrane during the rising phase of the action potential is due to
an increase in sodium resistance.
an increase in sodium connectance.
an increase in the sodium equilibrium potential.
an increase in sodium conductance.
The refractory period occurs because
sodium and potassium concentrations must be restored, and the "battery" recharged, before another action potential can be generated.
voltage-gated channels become inactivated for a short time following an action potential.
pre-synaptic inhibition prevents over-firing and cellular exhaustion.
the neuron cannot fire again until the membrane potential returns to below threshold.
Which of the following is a function of astrocytes?
Produce cerebrospinal fluid
secrete growth factors
transport newly synthesized proteins
line the external surfaces of CNS
Can an action potential be properly conducted if we removed the myelin sheaths of a previously myelinated axon?
No, because an axon can only conduct action potentials if it is myelinated
Yes, the axon can still conduct an action potential but it would be slower
No, because a previously myelinated axon is structurally different from an unmyelinated axon
Yes, because myelin is not responsible for action potential conduction
Tampering with which of the following would affect a neuron's resting membrane potential?
Voltage gated channels, because they affect how depolarized the cell can get
Leaky channels, because they affect ion permeability
Ligand gated channels, because they allow neurotransmitter binding
Mechanically gated channels, because they respond to membrane stretching
The Nernst equation calculates the equilibrium potential of an ion by considering:
Concentrations of the ion both inside and outside the cell
The action potential threshold of the cell
The permeability of the ion to the cell
The electrical charge of the ion
What non-myelinating function do Schwann cells provide?
Structural support-- hold nerves in place
Providing nutrients-- circulate CSF
Clear debris-- phagocytosis
Maintain ionic concentrations-- take up ions
What part of the neuron is considered the main integrative component?
Dendrites
Soma
Axon Hillock
Axon
Axon Terminal
Which of the following macroglia is INCORRECTLY
matched with its function
Oligodendrocytes: CNS myelin formation
Radial Glia: regulates CSF production/composition
Schwann Cells: PNS myelin formation
Astrocytes: general homeostatic maintenance
How do charged/larger molecules pass through the phospholipid
bilayer to get into the cell?
Only small non-charged molecules are able to get into the cell.
They locate cholesterol poor regions of the membrane that will
grant them entry into the cell.
Specific membrane proteins allow for certain substances to travel
through them to gain entry into the cell.
They diffuse through both the hydrophilic polar heads
and the hydrophobic fatty acid tail regions.
Which class of protein is synthesized by free ribosomes?
Cytosolic
Peripheral
Membrane-associated
Integral
A voltage sensitive ion channel is a channel:
That allows different ions to pass through when the
membrane potential is near zero than when it does when the
membrane potential is near resting potential
That desensitizes when the neuron depolarizes
That becomes non-functional when the membrane
becomes positive inside
Whose conductance to an ion changes as the
membrane potential changes
The motor protein kinesin is associated with _____________ transport while
the motor protein dynein is associated with __________ transport.
Fast anterograde, fast retrograde
Fast retrograde, fast anterograde
Slow axoplasmic flow, fast retrograde
Slow axoplasmic flow, fast anterograde
According to the “neural code”, the magnitude of a given stimulus
will be coded by:
A. The time duration of the action potentials
B. The amplitude of the action potentials
C. The frequency train of the action potentials
B and C
Which phase of the action potential would be affected if tetraethylammonium (TEA) were injected into a neuron?
The rising phase/depolarization -- voltage gated sodium channels would be blocked
The rising phase/depolarization-- voltage gated potassium channels would be blocked
The falling phase/repolarization-- voltage gated sodium channels would be blocked
The falling phase/repolarization-- voltage gated potassium channels would be blocked
What would happen to the equilibrium potential of Cl- if we DECREASED the extracellular concentration of the ion?
It would cause no change because Cl- is not permeable to the membrane
Not enough information
It would cause E(Cl-) to shift
It would cause E(Cl-) to shift positive
What voltage gated Na+ channel activity is associated when there is enough depolarization to meet action potential threshold?
The channel's activation gate rapidly opens and inactivation gate is triggered to slowly close
The channel's inactivation gate rapidly opens and activation gate is triggered to slowly close
Both activation and inactivation gates rapidly open
Nothing, because potassium channel activity responds first
Measurement of the net current flowing across the membrane of a neuron can be made with
An extracellular electrode
a voltage clamp device
a current clamp device
Both voltage clamps and current clamps
Which of the following matches the morphology of the pictured cell
Multipolar cell
Unipolar cell
Pseudo unipolar cell
Bipolar cell
Multimeric proteins like ion channels reflect:
secondary structure, where alpha helices and beta pleated sheets form
tertiary structure, where subunits associate together
quaternary structure, where subunits associate together
tertiary structure, where various types of intermolecular forces occur
Why is a neuron at rest more permeable to K+ than Na+?
There are more leaky K+ channels than Na+ channels
There are more voltage gated K+ channels than Na+ channels
There are more ligand gated K+ channels than Na+ channels
The neuron is not more permeable to K+ than Na+
What would happen to the equilibrium potential of Na+ if its extracellular concentration DECREASED?
The E(Na+) would shift positive
The E(Na+) would shift negative
It depends on if Na+ permeability changes
Not enough information
Most dendritic membrane cannot carry an action potential because
dendrites are too small in diameter
it lacks voltage-sensitive sodium channels
dendrites are too far from the spike initiation zone
its space constant is usually too small to let a post-synaptic potential reach threshold
As a rule, saltatory conduction is faster than non-saltatory conduction because
myelinated neurons have a lower internal resistance than do non-myelinated ones, thereby leading to faster conduction.
myelinated axons are bigger than non-myelinated ones, and larger diameter axons conduct faster.
the concentration of sodium channels at the nodes generates much larger than normal Na+ currents, which generate faster conduction
the insulation provided by myelin forces the depolarizing current farther down the axon, thereby allowing the AP to skip parts of the membrane.
Postsynaptic potentials are associated with:
Mechanically gated channels
2nd messenger gated channels
Ligand gated channels
Voltage gated channels
Neurons generally have which of the following concentrations of ions INTERNALLY (relative to extra-cellular space)?
High K+, high Na+, low Cl-
High K+, low Na+, low Cl-
Low K+, high Na+, low Cl-
Low K+, low Na+, low Cl-
