29 Questions
What is responsible for depolarizing the cell and initiating the action potential?
Sodium entering the cell down its chemical and electrical gradient
At what point in the action potential does the Na+ inactivation gate begin to close?
At the peak of the action potential
What is the approximate peak potential reached during an action potential in a neuron?
+30mV
During repolarization, what causes the return of the cell's membrane potential to its resting state?
K+ channels closing
What event marks the completion of an action potential in a neuron?
After hyperpolarization is initiated
Which process is responsible for maintaining the resting membrane potential in a neuron?
Na+/K+ ATPase-pump activity
What is the approximate resting membrane potential of a mammalian neuron?
-70mV
Which ion has the highest concentration outside the mammalian neuron at resting potential?
Na+
What is the main energy source used by Sodium-potassium ATPase pumps to maintain ion gradients?
ATP
What is the role of open potassium channels in the neuronal membrane at resting potential?
Facilitate K+ ions moving out of the cell
What happens to the concentration of Cl- ions in the inner chamber of the artificial membrane model at equilibrium?
Increases
How many Na+ ions are pumped out of the cell by the Sodium-potassium ATPase pumps for every 2 K+ ions pumped in?
3 Na+ out for 2 K+ in
What part of the neuron is responsible for receiving signals from other neurons?
Cell body
Where are action potentials typically initiated in a neuron?
Axon hillock
Which organelle houses most of the neuron's organelles?
Cell body
What glial cells improve the efficiency of the axon by providing myelin sheaths?
Astrocytes
What structure in a neuron increases the conduction velocity of an action potential?
Myelin sheaths
Which part of the neuron transmits signals to other cells at synapses?
Axon hillock
What is the equilibrium potential for K+ according to the text?
-90mV
If a cell membrane were permeable ONLY to Na+, what would be the hypothetical membrane potential according to the text?
+62mV
What is the Resting membrane potential range according to the text?
-65mV to -70mV
Which ion's equilibrium potential is closer to the Resting membrane potential according to the text?
K+
What does the Nernst Equation calculate according to the text?
The equilibrium potential for an ion
What does a positive equilibrium potential (+62mV) for an ion indicate according to the text?
An influx of that ion into the cell
What is the membrane potential threshold value for voltage-gated sodium channels to open?
-55mV
What is the nature of the action potential with respect to its amplitude?
It remains constant along the axon.
What type of potential is the action potential?
Graded potential
What event triggers the opening of voltage-gated sodium channels in neurons?
Strong depolarizing stimulus
What does the membrane potential threshold represent in neuronal action potential?
The membrane potential required for sodium channel activation
Test your knowledge on the process of neuronal action potential, from depolarization to repolarization. Understand the role of Na+ and K+ ions in generating an action potential.
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