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The most important diffusible ion in the establishment of the membrane potential is
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Human Physiology
- Define the following terms: a. depolarization b. repolarization c. passive transport d. active transport e. voltage-gated channelarrow_forwardWhich of the following statements about membrane ion channels is incorrect? a. mechanically gated channels respond to physical deformation b. ligand-gated channels respond to neurotransmitters c. voltage-gated channels respond to changes in membrane potential d. leakage channels have gates and are always open e. none of the abovearrow_forwardThe resting membrane potential results fromA. uneven distribution of ions across the cell membrane only.B. differences in membrane permeability to Na+ and K+ onlyC. activity of the sodium/potassium pump only.D. uneven distribution of ions across the cell membrane, differences in membrane permeability to Na+ and K+, and sodium/potassium pump activityarrow_forward
- The membrane potential across a cell membrane can be thought of as a "blend" or weighted average of a. the concentrations of Na+ and K+ ions in the extracellular fluid b. the concetrations of Na+ and K+ ions in the cytoplasm c. the concentrations of all permeable ions in the cytoplasm d. the membrane potenial before and after the action potential e. None of the above answer choices correctly completes the sentencearrow_forwardMark the following statements as true or false. If a statement is false, correct it to make a true statement. a. The resting membrane potential refers to the voltage difference across the membranes of excitable cells at rest. b. The concentration of Na+ is highest in the cytosol, and the concentration of K+ is highest in the extracellular fluid. c. The Na+>K+ pumps and gated channels maintain the Na+ and K+ gradients necessary for action potentials to occur. d. A depolarization is a change in membrane potential that makes the potential less negative. e. A local potential is a change in membrane potential that conducts the long-distance signals of the nervous systemarrow_forwardIn a neuron, which of the following types of transport occur passively through channel proteins? A. Movement of Na+ into the cell B. Movement of Na+ out of the cell C. Movement of K+ into the cell D. Both A & Carrow_forward
- Choose the correct answer: A) When the voltage gated K+ channels open K+ moves down its concentration gradient from the ECF to inside the cell. O B) The value for resting membrane potential is closer to the EK+ (Equilibrium potential for K+) than the ENa+ O C) When the membrane potential is at rest the membrane is more permeable to Na+ than it is to K+ O D) Closing of the voltage-gated Na+ channels increases the permeability of the membrane to Na+arrow_forwardWhich of the following molecules is not involved in the maintenance of the resting membrane potential? a. potassium cations b. ATP c. voltage-gated ion channels d. calcium cationsarrow_forwardWhich of the fallowing is required to generate a membrane potential? I. A concentration gradient of ions II. Presence of neurotransmitters II. Semipermeable membrane a) II only b) I only c) II and III d) I and IIIarrow_forward
- Depolarization and repolarization changes that occur during the action potential are produced by a. Negative feedback loops b. Channel mediated transport c. Simple diffusion of ions down their concentration gradient d. Active transport pumps along the neuron membranearrow_forwardDescribe the contribution of each of the following to establishing and maintaining membrane potential: (a) the Na+K+ pump, (b) passive movement of K+ across the membrane, (c) passive movement of Na+ across the membrane, and (d) the large intracellular anions.arrow_forwardAssume that a membrane permeable to Na+ but not to Cl- separates two solutions. The concentration of sodium chloride on side 1 is higher than on side 2. Which of the following ionic movements would occur? a. Na+ would move until its concentration gradient is dissipated (until the concentration of Na+ on side 2 is the same as the concentration of Na+ on side 1). b. Cl- would move down its concentration gradient from side 1 to side 2. c. A membrane potential, negative on side 1, would develop. d. A membrane potential, positive on side 1, would develop. e. None of the preceding is correct.arrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning