Pearson eText Human Physiology: An Integrated Approach -- Instant Access (Pearson+)
8th Edition
ISBN: 9780135212905
Author: Dee Silverthorn
Publisher: PEARSON+
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Textbook Question
Chapter 8.3, Problem 8CC
Would a cell with a resting membrane potential of −70 mV depolarize or hyperpolarize in the following cases? (You must consider both the concentration gradient and the electrical gradient of the ion to determine net ion movement.)
- (a) Cell becomes more permeable to Ca2+
- (b) Cell becomes less permeable to K+.
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If 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 sodium
Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item best represents the forces and fluxes for a membrane potential of -40 mV (a, b, c, or d)? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.
Calculate the equilibrium membrane potentials to be expected across a membrane at 37 °C, with a NaCl concentration of 0.10 M on the “right side” and 0.01 M on the “left side”, given the following conditions. In each case, state which side is (+) and which is (-).
(a) Membrane permeable only to Na+
(b) Membrane permeable only to Cl–
(c) Membrane equally permeable to both ions
Chapter 8 Solutions
Pearson eText Human Physiology: An Integrated Approach -- Instant Access (Pearson+)
Ch. 8.1 - Organize the following terms describing functional...Ch. 8.2 - Where do neurohormone-secreting neurons terminate?Ch. 8.2 - What is the difference between a nerve and a...Ch. 8.2 - Draw a chain of three neurons that synapse on one...Ch. 8.2 - What is the primary function of each of the...Ch. 8.2 - Name the two glial cell types that form myelin....Ch. 8.3 - Given the values in Table 8.2, use the Nernst...Ch. 8.3 - Would a cell with a resting membrane potential of...Ch. 8.3 - Would the cell membrane depolarize or...Ch. 8.3 - Match each ions movement with the type of graded...
Ch. 8.3 - Prob. 11CCCh. 8.3 - What is the difference between conductance and...Ch. 8.3 - If you put ouabain, an inhibitor of the Na+-K+...Ch. 8.3 - The pyrethrin insecticides, derived from...Ch. 8.3 - When Na+ channel gates are resetting, is the...Ch. 8.3 - A stimulating electrode placed halfway down an...Ch. 8.3 - Place the following neurons in order of their...Ch. 8.4 - Prob. 18CCCh. 8.4 - Prob. 19CCCh. 8.4 - Prob. 20CCCh. 8.4 - Prob. 21CCCh. 8.4 - Prob. 22CCCh. 8.4 - Classify the H+-neurotransmitter exchange as...Ch. 8.4 - Prob. 24CCCh. 8.4 - Prob. 25CCCh. 8.4 - Is Na+-dependent neurotransmitter reuptake...Ch. 8.5 - In Figure 8.24e, assume the postsynaptic neuron...Ch. 8.5 - In the graphs of Figure 8.24a, b, why doesnt the...Ch. 8.5 - Prob. 29CCCh. 8.5 - Prob. 30CCCh. 8 - List the three functional classes of neurons, and...Ch. 8 - Somatic motor neurons control __________, and...Ch. 8 - Prob. 3RQCh. 8 - Prob. 4RQCh. 8 - Prob. 5RQCh. 8 - Prob. 6RQCh. 8 - Axonal transport refers to the (a) release of...Ch. 8 - Match the numbers of the appropriate...Ch. 8 - Arrange the following events in the proper...Ch. 8 - List the four major types of ion channels found in...Ch. 8 - Prob. 11RQCh. 8 - An action potential is (circle all correct...Ch. 8 - Choose from the following ions to fill in the...Ch. 8 - What is the myelin sheath?Ch. 8 - List two factors that enhance conduction speed.Ch. 8 - Prob. 16RQCh. 8 - Draw and label a graph of an action potential....Ch. 8 - Prob. 18RQCh. 8 - Prob. 19RQCh. 8 - Create a map showing the organization of the...Ch. 8 - Prob. 21RQCh. 8 - Prob. 22RQCh. 8 - Prob. 23RQCh. 8 - Prob. 24RQCh. 8 - The presence of myelin allows an axon to (choose...Ch. 8 - Define, compare, and contrast the following...Ch. 8 - Prob. 27RQCh. 8 - Prob. 28RQCh. 8 - Prob. 29RQCh. 8 - Prob. 30RQCh. 8 - An unmyelinated axon has a much greater...Ch. 8 - The GHK equation is sometimes abbreviated to...Ch. 8 - In each of the following scenarios, will an action...
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- One of the important uses of the Nernst equation is in describing the flow of ions across plasma membranes. Ions move under the influence of two forces: the concentration gradient (given in electrical units by the Nernst equation) and the electrical gradient (given by the membrane voltage). This is summarized by Ohms law: Ix=Gx(VmEx) which describes the movement of ion x across the membrane. I is the current in amperes (A); G is the conductance, a measure of the permeability of x, in Siemens (S), which is I/V;Vm is the membrane voltage; and Ex is the equilibrium potential of ion x. Not only does this equation tell how large the current is, but it also tells what direction the current is flowing. By convention, a negative value of the current represents either a positive ion entering the cell or a negative ion leaving the cell. The opposite is true of a positive value of the current. a. Using the following information, calculate the magnitude of Na [ Na+ ]0=145mM,[ Na+ ]i=15mM,Gna+=1nS,Vm=70mV b. Is Na+ entering or leaving the cell? c. Is Na+ moving with or against the concentration gradient? Is it moving with or against the electrical gradient?arrow_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_forwardConformational 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_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_forwardSeparately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item best represents the forces and fluxes for a membrane potential of 0 mV?arrow_forwardDraw the current changes caused by a single voltage gated Potassium channel when the membrane is voltage-clamped at different voltage values (see below). Assume an equilibrium potential for potassium of -70mV and don't worry about exact values for the currents (approximations are fine). Label the axes on the traces and describe how the dynamics of individual voltage gated potassium channels come together to form the macroscopic K+ currents during depolarization. . a. @Resting Membrane Potential = -70 mV b. @Voltage Step = -20 mV c. @Voltage Step = +50mVarrow_forward
- Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+. The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item best represents the forces and fluxes for a membrane potential of -60 mV? Pick one of the four tables in the included image please for your answer.arrow_forwardCalculate the equilibrium membrane potentials to be expected across a membrane at 37 ∘C, with a NaCl concentration of 0.50M on the "right side" and 0.08 M on the "left side", given the following conditions. In each case, state which side is (+) and which is (−). (a)Membrane permeable only to Na+.arrow_forwardIntracellular potentials are on the order of -100mV, whereas extracellular potentials are OmV. Assuming these values, answer the following questions. (a) What is the electric potential energy of a chloride ion (CI-) inside a cell? (b) What about outside the cell? (c) What is the probability of finding a Cl- inside the cell relative to finding it outside the cell? Assume that T=310K. P(inside) P(outside) (d) If the concentration of Cl- outside the cell is 100mM, what is the expected concentration inside the cell?arrow_forward
- Calculate the equilibrium membrane potentials to be expected across a membrane at 37 ∘C, with a NaCl concentration of 0.50 M on the "right side" and 0.08 M on the "left side", given the following conditions. In each case, state which side is (+) and which is (−). Membrane equally permeable to both ions.arrow_forwardWhat is the equilibrium membrane potential due to Na+ ions if the extracellular concentration of Na+ ions is 154 mM and the intracellular concentration of Na+ ions is 23 mM at 20 ∘C ?arrow_forwardMembrane potential in cells is constantly fluctuating. These fluctuations are called graded potentials and we will learn more about them in future lectures. Look at the fluctuating graded potential in the graph as an example. If Cl- generally has a relatively low membrane permeability, how would increasing Cl- permeability affect this graph?arrow_forward
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