WorksheetsVoltage-Dependent Membrane Permeability
Total questions: 12
Worksheet time: 7mins
What best describes use of the voltage clamp method in neuroscience?
measuring ionic movement in a living organism
measuring the resting membrane potential of a cell
manipulation of the resting membrane potential in a cell
changing the voltage of a cell
controlling the membrane potential of a cell while measuring the resulting ionic currents
Which statement about Na+ permeability during an action potential is most accurate?
It is long lasting.
It is responsible for the rising phase of the action potential.
It is responsible for the falling phase of the action potential.
It restores the membrane potential to its usual level following the action potential.
All of the above
The voltage clamp method controls the _______ at any desired level.
amplitude of an action potential
frequency of an action potential
membrane potential
K+ current
Na+ current
The classic voltage clamp technique would be suitable for which application?
Indirect measurement of unidirectional current flowing through cell membrane.
Direct measurement of current flowing through the cell membrane.
Measurement of current flowing through a single ion channel.
Study of the ionic composition of the intracellular environment.
Evaluation of effects of large intracellular molecules on the function of ion channels.
Which current corresponds to a flow of Na+ in response to a depolarizing stimulus in a giant axon of a squid?
Outward capacitive current.
Transient inward current.
Delayed outward current.
Prolonged outward current.
Which is the key event at a membrane potential of 0 mV?
The late outward current increases in magnitude.
The late outward current decreases in magnitude.
The early current reverses its polarity.
The early and late currents flow inward.
The early current is at its maximum.
In the experiments conducted by Hodgkin and Huxley, the early current disappeared if the membrane was clamped at _______ mV.
-26
+26
+52
+65
Practically speaking, how would you determine that Na+ influx into a cell underlies the early current?
Replace intracellular Na+ with its radioactive form and trace its movement across the membrane.
Remove Na+ from the extracellular compartment and assess the early current under new conditions.
Use the voltage clamp method to measure the current.
Remove K+ from the intracellular compartment and assess the early current under the new conditions.
Treat the cell with tetraethylammonium.
Membrane potential depolarizes, Na+ channels open, Na+ current increases, _______, _______, and _______. (Select all that apply)
K+ channels open
Na+ channels close
Na+ current decrease
Na+ current increase
membrane potential hyperpolarizes
Which statement correctly differentiates between the passive and active current in a myelinated axon?
The passive current flows only in the nodes of Ranvier, unlike the active current.
The active current flows only in the nodes of Ranvier, unlike the passive current.
The passive current flows in one direction along the axon, unlike the active current.
The action potential propagation depends on the passive current only.
The action potential propagation depends on the active current only.
Which symptom(s) is characteristic of patients with multiple sclerosis?
Blindness due to lesions of the optic nerve and its myelin
Unilateral motor weakness due to lesions of the corticospinal tracts
Abnormal somatic sensations due to lesions of somatosensory pathways
Seizures from kindling of action potentials in adjacent neurons due to loss of insulation around axons
All of the above can potentially occur in MS
What is the primary pathophysiological mechanism associated with multiple sclerosis?
Axon damage
Immune cell infiltration
Immune response within the nervous system
Loss of trophic support of the axon
