Concept explainers
To draw:
A graph depicting the changes in potential during depolarization, repolarization, and hyperpolarization as compared to resting membrane potential.
Introduction:
All body cells have a membrane potential, which divides the positive and negative charges throughout the membrane. This potential is associated with uneven distribution of sodium (Na+), potassium (K+) and large intracellular protein anions, between the ICF (intracellular fluid) and the ECF (extracellular fluid) as well as to the plasma membrane's differential permeability. When the cell is electrically resting and does not produce electrical signal, the constant membrane potential is called resting membrane potential.
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Human Physiology: From Cells to Systems (MindTap Course List)
- Conformational changes in channel proteins brought about by voltage changes are responsible for opening and closing Na+ and K+ gates during the generation of an action potential. (True or false?)arrow_forwardDraw and label an action potential, indicating the ion movements responsible for the rising phase and the falling phase.arrow_forwardDefine an action potential.arrow_forward
- At the peak of an action potential, would the relative permeability of Na be higher than K? Which ion would be the least permeable to the membrane during falling phase?arrow_forwardDescribe the events of an action potential in terms of ions and gates or channels beginning with the generation of a local potential through the re-establishment of resting membrane potential.arrow_forwardDefine depolarization, repolarization, and hyperpolarization in terms of how it affects the membrane potential of an excitable cell.arrow_forward
- If: membrane potential=-70mV, ENa=+60mV, and Ex=-90mV, consider which directions Na+ and K+ will leak across the membrane. If both ions are crossing the membrane, what is the most important factor in determining whether membrane potential will become more positive or more negative?arrow_forwardDescribe in detail what resting membrane potential is and what role the sodium/potassium leakage channels and the sodium-potassium pump play in maintaining this potential.arrow_forwardDescribe the contribution of each of the following to the establishment and maintenance of membrane potential: Part A Na+K+ Pump Passive movement of K+ across the membrane Passive movement of Na+ across the membranearrow_forward
- Match each type of membrane potential (resting, threshold, graded, or action) to its definition: a) The membrane potential at which voltage gated sodium channels open. b) The membrane potential that triggers the action potential. c) Change in membrane potential that may or may not reach threshold and that may be depolarizing or hyperpolarizing. d) Rapid, strong depolarization followed by immediate repolarization. This potential is self-renewing if the right ion channels are nearby.arrow_forwardDescribe the ion movement across the cell membrane during the following stages: resting potential, threshold potential, depolarization, repolarization.arrow_forwardWhat ion is the major influence on the resting membrane potential? Explain its role.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage LearningHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning