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Module 2 - Action Potential & Neuronal
Synaptic Connections (Midterm) Verified
and Updated Questions and Answers (100%
Correct Answers)
The membrane potential is the difference in
the
Answer: electrical charge between the interior and exterior of the cell, and is
established by varying concentrations of electrically charged ions - predominantly
sodium, potassium and chloride ions - in the neuron versus the surrounding
extracellular space
The membrane of the cell is composed of a lipid bilayer, which does not allow for the
free movement of
Answer: ions into or out of the cell. Rather, ions move through channels or energy
dependent pumps (made of proteins) that are embedded within the lipid bilayer
membrane.
the sodium concentration is ____ in the extracellular space (___ mEq/L) and
____ in the neuron cell body (____Eq/L).
Answer: the sodium concentration is high in the extracellular space (142 mEq/L) and
low in the neuron cell body (14 mEq/L).
As there is more sodium outside of the cell
than inside, there is a chemical gradient favoring influx of sodium into the cell.
The membrane potential of the neuron cell body is _________; as
such, there is an electrical gradient favoring influx of ________.
Answer: The membrane potential of the neuron cell body is negative (-65 mV); as
such, there is an electrical gradient favoring influx of the positively charged sodium
ion into the cell.
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In the inactivated state, these electrical and chemical gradients are maintained by the
energy-dependent
Answer: Na-K ATPase (aka sodium pump) that extrudes
three sodium ions out of the cell in exchange for two potassium ions into the cell.
the potassium concentration is _____ inside the neuron cell body (_____ mEq/L) and
_____ in the extracellular space (_____ mEq/L). As there is _____ potassium inside the
cell, there is a chemical gradient favoring efflux of potassium _____ the cell.
Answer: the potassium concentration is high inside the neuron cell body (120
mEq/L) and low in the extracellular space (4.5 mEq/L). As there is more potassium
inside the cell, there is a chemical gradient favoring efflux of potassium out of the
cell.
the chloride concentration is ____ in the extracellular space, but ____ in the
neuron cell body. As such, there is a chemical gradient favoring ____ of chloride ____
the cell.
Answer: the chloride concentration is high in the extracellular space, but low in the
neuron cell body. As such, there is a chemical gradient favoring influx of chloride
into the cell.
When the membrane potential becomes less negative or depolarized; this is referred
to as an
Answer: excitatory postsynaptic potential (EPSP).
excitatory postsynaptic potential (EPSP) can occur via several mechanisms, including:
Answer: -Opening of sodium channels, allowing influx of the positive ion into the
postsynaptic neuron.
-Closing of chloride channels, preventing influx of the negative ion into the
postsynaptic neuron.
-Closing of potassium channels, preventing efflux of the positive ion out of the
postsynaptic neuron.
-Various changes in the intracellular metabolism or structure of the postsynaptic
neuron, such as an increase in the number of excitatory membrane receptors or a
decrease in the number of inhibitory receptors.
When the membrane potential becomes more negative or hyperpolarized; this is
Module 2 - Action Potential & Neuronal
Synaptic Connections (Midterm) Verified
and Updated Questions and Answers (100%
Correct Answers)
The membrane potential is the difference in
the
Answer: electrical charge between the interior and exterior of the cell, and is
established by varying concentrations of electrically charged ions - predominantly
sodium, potassium and chloride ions - in the neuron versus the surrounding
extracellular space
The membrane of the cell is composed of a lipid bilayer, which does not allow for the
free movement of
Answer: ions into or out of the cell. Rather, ions move through channels or energy
dependent pumps (made of proteins) that are embedded within the lipid bilayer
membrane.
the sodium concentration is ____ in the extracellular space (___ mEq/L) and
____ in the neuron cell body (____Eq/L).
Answer: the sodium concentration is high in the extracellular space (142 mEq/L) and
low in the neuron cell body (14 mEq/L).
As there is more sodium outside of the cell
than inside, there is a chemical gradient favoring influx of sodium into the cell.
The membrane potential of the neuron cell body is _________; as
such, there is an electrical gradient favoring influx of ________.
Answer: The membrane potential of the neuron cell body is negative (-65 mV); as
such, there is an electrical gradient favoring influx of the positively charged sodium
ion into the cell.
, Inquire through: | Professional | Confidential Support
In the inactivated state, these electrical and chemical gradients are maintained by the
energy-dependent
Answer: Na-K ATPase (aka sodium pump) that extrudes
three sodium ions out of the cell in exchange for two potassium ions into the cell.
the potassium concentration is _____ inside the neuron cell body (_____ mEq/L) and
_____ in the extracellular space (_____ mEq/L). As there is _____ potassium inside the
cell, there is a chemical gradient favoring efflux of potassium _____ the cell.
Answer: the potassium concentration is high inside the neuron cell body (120
mEq/L) and low in the extracellular space (4.5 mEq/L). As there is more potassium
inside the cell, there is a chemical gradient favoring efflux of potassium out of the
cell.
the chloride concentration is ____ in the extracellular space, but ____ in the
neuron cell body. As such, there is a chemical gradient favoring ____ of chloride ____
the cell.
Answer: the chloride concentration is high in the extracellular space, but low in the
neuron cell body. As such, there is a chemical gradient favoring influx of chloride
into the cell.
When the membrane potential becomes less negative or depolarized; this is referred
to as an
Answer: excitatory postsynaptic potential (EPSP).
excitatory postsynaptic potential (EPSP) can occur via several mechanisms, including:
Answer: -Opening of sodium channels, allowing influx of the positive ion into the
postsynaptic neuron.
-Closing of chloride channels, preventing influx of the negative ion into the
postsynaptic neuron.
-Closing of potassium channels, preventing efflux of the positive ion out of the
postsynaptic neuron.
-Various changes in the intracellular metabolism or structure of the postsynaptic
neuron, such as an increase in the number of excitatory membrane receptors or a
decrease in the number of inhibitory receptors.
When the membrane potential becomes more negative or hyperpolarized; this is
