53 Questions
What is the term used to describe the charge difference across the membrane of cells?
Membrane potential
What instrument is used to measure the membrane potential of cells?
Voltmeter
In which units is the membrane potential typically measured?
Millivolts
What type of cells are capable of changing their membrane potential to produce action potentials?
Excitable cells
What is the average resting membrane potential for most neurons?
-70 mV
Which pump plays a role in creating the charge difference at resting membrane potential by pumping out 3 Na+ for every 2 K+ it brings in?
Na+/K+ pump
Which of the following cells are NOT capable of producing graded potentials or action potentials when stimulated?
Blood cells
What ions contribute to the differences in concentrations inside and outside the cell, leading to the resting membrane potential?
Na+, K+, Cl-
What is the typical resting membrane potential for excitable cells like muscle cells and sensory receptors?
-70 mV
Why are excitables cells capable of changing their membrane potential?
To produce graded potentials and action potentials when stimulated
What is the net effect each time the Na+/K+ pump carries out its function?
Loss of 1 positive charge
What contributes to the negative charge inside the cell at resting membrane potential?
Presence of fixed anions
What is the primary reason for the relatively more negative charge inside the cell compared to outside?
Movement of K+ out of the cell
What term is used to describe changes in the charge difference across the membrane of variable strength?
Graded potentials
'Depolarization' events make it more likely for a response to happen in a cell because they make the cell more ___.
Positive inside
'Hyperpolarization' events are referred to as inhibitory because they make it less likely for a response to happen by making the cell more ___.
Negative inside
What is the typical threshold level of depolarization for most neurons to 'fire'?
-55 mV
'Action potentials' rely on the opening and closing of which channels in neurons?
Voltage-gated sodium ion and voltage-gated potassium ion channels
'Repolarization' refers to the process where the cell returns back to resting membrane potential after ___ occurs.
'Depolarization'
'Graded potentials' occur in which parts of a neuron?
'Dendrites and cell body'
Match the following terms with their descriptions:
Depolarization = The cell becomes more positive inside Hyperpolarization = The cell becomes more negative than resting membrane potential Repolarization = The cell returns to resting membrane potential after depolarizing Action potentials = Brief, all-or-none electrical events where the cell temporarily becomes positive & then returns back to negative
Match the following types of membrane potential with their descriptions:
Resting membrane potential = Charge difference across the membrane when neuron is unstimulated Graded potentials = Variable strength changes in membrane potential Action potentials = Rely on opening and closing of specific channels in neurons Depolarization = Event that makes it more likely for a cell to respond
Match the following ions with their role in contributing to resting membrane potential:
Na+ = Higher concentration outside the cell K+ = Higher concentration inside the cell Cl- = Concentration differences contribute to charge imbalance Ca2+ = Minor contribution to resting membrane potential
Match the following ion movements with their effects on membrane potential:
Na+ moving into the cell = Makes the cell more positive inside K+ moving out of the cell = Makes the cell more negative inside Na+ moving out of the cell = Not mentioned in the text K+ moving into the cell = Not mentioned in the text
Match the following terms with their impact on cellular response:
Depolarization events = Make it more likely for a response to happen in the cell Hyperpolarization events = Make it less likely for a response to happen in the cell Repolarization events = Not mentioned in the text Graded potentials = Not mentioned in the text
Match the following terms with their descriptions:
Hyperpolarization = Events that make it less likely for a cell to respond Repolarization = Process of returning back to resting membrane potential after an event Excitable cells = Capable of changing membrane potential to produce action potentials Threshold level = Minimum depolarization needed for a neuron to 'fire'
Match the following events with their impact on membrane potential:
Na+/K+ pump function = Contributes to charge difference by pumping ions in and out of the cell Depolarization = Makes the cell more likely to respond by decreasing charge difference Hyperpolarization = Decreases likelihood of response by increasing charge difference Repolarization = Process of restoring charge balance after an event
Match the following descriptions with their corresponding terms:
Excitatory events = Make it more likely for a response to happen in the cell Inhibitory events = Make it less likely for a response to happen in the cell Graded potentials = Changes in charge difference across membrane of variable strength Action potentials = Only occur in the axon of a neuron and rely on specific ion channels
Match the following terms with their roles in cellular function:
Threshold level of depolarization = Determines if a neuron will 'fire' or not Net effect of Na+/K+ pump function = Results in a loss of 1 positive charge each time it pumps Fixed anions inside the cell = Contribute to the relatively negative charge inside at resting membrane potential Presence of K+ leakage channels = Allows K+ to move out, making the inside of the cell more negative
Match the following terms with their measurement units:
Membrane potential = Measured in millivolts (mV) Graded potentials = Changes in strength measured in mV Voltmeter = Instrument used to measure membrane potential Action potentials = Relies on specific voltage levels for firing
What is the significance of the overshoot during hyperpolarization in an action potential?
It makes the cell more negative than the resting membrane potential.
What role do chemically-regulated channels play in influencing membrane permeability?
They are controlled by neurotransmitters binding to receptors.
What is the primary function of leakage channels in a cell?
Maintaining the resting membrane potential.
Which ion channels open first during an action potential, leading to depolarization?
Sodium channels
What is the role of voltage-gated ion channels like potassium during an action potential?
Play a crucial role in repolarization and hyperpolarization.
How does an excitatory stimulus affect the membrane potential of a cell?
Triggers positive charges to enter the cell.
What happens when potassium channels remain open longer than necessary during an action potential?
The cell becomes more negative than its resting membrane potential.
Sodium channels open after potassium channels close during an action potential.
False
Leakage channels, such as sodium leakage channels, are always closed.
False
Chemically-regulated channels are influenced by neurotransmitters binding to receptors.
True
An inhibitory stimulus leads to negative charges entering the cell.
False
Hyperpolarization makes the cell more positive than the resting membrane potential.
False
The overshoot during hyperpolarization is caused by sodium channels remaining open longer than necessary.
False
Voltage-gated ion channels like calcium play a minimal role in neurons.
False
How does myelination influence the conduction speed of action potentials?
By allowing for saltatory conduction
What role does the axon diameter play in the conduction speed of action potentials?
Speeding up signal conduction
Which factor allows action potentials to maintain the same strength throughout?
Regeneration at each point along the axon
What influences the varying conduction speeds in different types of neurons?
Myelination and diameter of the axon
Match the following statements with their correct descriptions:
Action potentials are regenerated down the length of the axon = Maintain same strength throughout Refractory period prevents action potentials from moving backwards = Caused by inactivation of sodium channels Conduction speed of action potentials is influenced by myelination and diameter of the axon = Myelination allows for faster conduction Neurons with larger diameter axons conduct signals faster = Than those with thinner axons
Match the following terms with their effects on action potentials:
Hyperpolarization events = Prevent action potentials from moving backwards Saltatory conduction = Allows for faster conduction Myelination = Regenerates action potentials only at nodes of Ranvier Sodium diffusing triggers voltage-gated channels to open = Regeneration down the axon
Match the following factors with their impacts on conduction speed:
Myelination and diameter of the axon = Influence conduction speed Saltatory conduction = Faster conduction Axon diameter = Plays a role in conduction speed Nodes of Ranvier = Regeneration points for action potentials
Match the following descriptions with their related events:
Overshoot during hyperpolarization = Caused by sodium channels remaining open longer Depolarization events = Make it more likely for a response to happen Repolarization = Cell returns back to resting membrane potential after action potential Graded potentials occur in = Different parts of a neuron
Match the following ion movements with their effects on membrane potential:
Sodium diffusing triggers voltage-gated channels to open = Regeneration down the axon Potassium channels remaining open longer than necessary = Overshoot during hyperpolarization Na+/K+ pump function = Creates charge difference at resting membrane potential Calcium ions through voltage-gated channels = Minimal role in neurons
Learn about the charge difference across cell membranes known as membrane potential and how it is measured using a voltmeter in millivolts (mV). Explore the concept of resting membrane potential present in all cells.
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