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Questions and Answers
The passive current flow of a graded potential fades quickly due to the resistance of the plasma membrane.
True
The resting membrane potential typically ranges from ______ mV to -90 mV.
-40
The inside of the cell is negatively charged relative to the ______.
outside
The ______ is a key ion that has a higher concentration inside the cell and is a major contributor to the resting membrane potential.
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The ______-Potassium pump helps maintain the concentration gradients of sodium and potassium across the membrane.
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Changes in ion concentration gradients can directly affect the resting membrane ______.
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Study Notes
Graded Potentials
- Graded potentials fade quickly due to resistance in the plasma membrane.
- Resistance significantly affects the duration of graded potentials.
- Graded potentials can vary in amplitude.
Resting Membrane Potential
- The difference in electrical charge across the cell membrane when the cell is at rest.
- Typically ranges from -40 mV to -90 mV.
- The inside of the cell is negatively charged relative to the outside.
Factors Influencing Resting Membrane Potential
- Ion Concentration Gradients: The higher the concentration of an ion inside the cell compared to outside, the more that ion will tend to move out of the cell. This contributes to the negative charge inside the cell.
- Membrane Permeability: The cell membrane is more permeable to potassium (K+) than sodium (Na+). This means that potassium can more easily move across the membrane, contributing to the negative charge inside the cell.
- Sodium-Potassium Pump: This active transport protein pumps 3 sodium ions out of the cell and 2 potassium ions into the cell. This helps maintain the concentration gradients of sodium and potassium, which are crucial for the resting membrane potential.
- Leak Channels: These channels allow for the passive movement of ions across the cell membrane. Potassium leak channels are particularly important for maintaining the resting membrane potential.
Importance of Resting Membrane Potential
- Essential for the generation of action potentials in neurons and muscle cells.
- Influences cellular functions, signaling, and overall homeostasis.
Clinical Relevance
- Abnormal resting potentials can indicate pathological conditions like cardiac arrhythmias and muscle disorders.
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Description
This quiz focuses on the concepts of graded potentials in neuroscience, including the effects of plasma membrane resistance on current flow. Participants will evaluate statements concerning the stability and duration of graded potentials, as well as their characteristics. Test your understanding of these fundamental concepts in neurophysiology.
