Concept explainers
(a)
To determine: Whether a cell depolarize or hyperpolarize when Cl- channel opens.
Introduction: Polarization is the electric difference across the cell membrane. It is the process of producing positive and negative electric charges inside the cell with respect to the surroundings.
(b)
To determine: Whether a cell depolarize or hyperpolarize when K+ channel opens.
Introduction: Resting potential of a cell is -70 mV. When resting potential alters, the cell either becomes hyperpolarize or depolarize. It becomes more negative or more positive.
(c)
To determine: Whether a cell depolarize or hyperpolarize when Na+ channel opens.
Introduction: At rest, a neuron has a resting potential of -70 mV. This states that inside of the cell is more negatively charged than the surrounding. When resting potential increases or decreases, a neuron transmits the message.
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EBK HUMAN PHYSIOLOGY
- Which statement is TRUE regarding the Na+ voltage-gated channel in neurons? A) Similar to the potassium ion channel, it exists as a tetramer in the membrane. B) Aspartate residues are part of the voltage-sensing helices. C) Positive membrane potentials on the extracellular side will close the channel. D) Ion specificity comes from the voltage-sensing helices.arrow_forwardThe resting membrane potential is established by? The Na+/K+-ATPase pumping Na+ into the cell and K+ out of the cell The Na+/K+-ATPase pumping K+ into the cell and Na+ out of the cell A larger diffusion of K+ out of the cell compared to diffusion of Na+ into the cell A larger diffusion of K+ into the cell compared to diffusion of Na+ out of the cell a) and d) b) and c)arrow_forwardIf a cell with the following ion concentrations had a resting membrane potential of -40mV which of the following can you conclude? Extracellular: Cl- = 110 mM, Na+ = 145 mM, K+ = 5mM. Intracellular Cl- = 20 mM, Na+ = 10 mM, K+ = 140mM a) At rest it is only permeable to potassium b) At rest it has some permeability to more than one of these ions c) At rest it is only permeable to chloride d) Rest it is not permeable to sodiumarrow_forward
- The differences in relative concentrations of ions inside and outside the cell act as an electrical force. The specific ion(s) MOST important to establishing the resting potential in neurons would be Multiple Choice a) Na+. b) K+. c) intracellular anions (e.g., proteins). d) H+. e) Na+, K+, and intracellular anions are all important.arrow_forwardInterpret the effect of hyperkalemia with reference to Goldman’s equation. a) What happens to rate of K+ diffusion at the MRP equilibrium with elevated extracellular [K+] (and unchanged intracellular [K+])?b) Since this diffusion rate determines the “permeability” of the cell to that K+ ion, what happens to PK+ as a result of this elevated extracellular K+? (Hint- it HAS changed.)c) Since PK+ has changed, and PNa+ is unchanged, what happens to the MRP as a result of this change in PK+? Explain with specific reference to Goldman’s equation but there is no need to cite or calculate any specific numbers, just generalize the result.arrow_forwardWhich is the state of voltage gated channel when the membrane potential has changed from resting (-40mV) to +20mV? a)Closed state b)Open state c)İnactivated statearrow_forward
- The resting membrane potential…A) Can be approximated using the Nernst equation.B) Is established by a difference in charges across the cell membrane, with the inside more positive than the outside.C) Has no influence on the driving force for flow of a particular ion across the cell membrane.D) Is more dependent on the passive flow of potassium vs. sodium ions through leak channels across the cell membrane.E) Stays the same during an action potential.arrow_forwardCells normally exist in a steady state where the intracellular ions remain constant. How is this steady state achieved by limiting the effect of extracellular ions on ions in the cells?arrow_forwardIn the experimental setup described in the attached figure (Figure 2.5 of the textbook), the middle panel shows two compartments with 10 mM KCI on the left (inside) and 1 mM KCL on the right (outside), separated by a membrane that is permeable to K+. What would initially happen if you replaced the KCI solutions with NaCl solutions (1 mM on the left or inside and 10 mM on the right or outside)? (A) Inside 1 mM KC Voltmeter Outside 1 mM KCI Permeable to K Nonet Bux of K (B) Initial conditions Initially Inside Outside 10 mM KC 1 mM KC Net flux of K from inside in outside → At equilibrium --58 mY Inside Outside 10 mM KCI 1 mM KC Flux of K from inside to outside balanced by opposing membrare potential Membrane potential (A) -116 [KL] 4 tended change O Na+ would move up its concentration gradient from the left (inside) to the right (outside) compartment. O Na+ would move down its concentration gradient from the right (outside) to the left (inside) compartment. O Na+ would not move because…arrow_forward
- What is the application of electrical application in Cell Membrane potential gradient?arrow_forwardExplain the mechanism of action of the Na+/K+ pump. If these pumps became non-functional due to a genetic mutation, what do you think would be the expected effect on the electrochemical membrane potential of the cell? Explain your reasoning.arrow_forwardThe inside negative membrane potential is a force that helps support... a.) the movement of (neutral) nonelectrolytes into the cell b.) the movement of cations into the cell c.) the movement of (neutral) nonelectrolytes out of the cell d.) the movement of anions into the cellarrow_forward
- Human Physiology: From Cells to Systems (MindTap ...BiologyISBN:9781285866932Author:Lauralee SherwoodPublisher:Cengage Learning