d. Much of the experimental research on the propagation of nerve signals has focused on an especially large axon found in the squid. The axon's Nernst potential for K+ ions is -115 mV at a temperature of 15°C. The ion concentration outside the axon is 2.0 mM. What is the concentration inside the axon? 0.02 mm mM

d. Much of the experimental research on the propagation of nerve signals has focused on an especially large axon found in the squid. The axon's Nernst potential for K+ ions is -115 mV at a temperature of 15°C. The ion concentration outside the axon is 2.0 mM. What is the concentration inside the axon? 0.02 mm mM

Anatomy & Physiology

1st Edition

ISBN:9781938168130

Author:Kelly A. Young, James A. Wise, Peter DeSaix, Dean H. Kruse, Brandon Poe, Eddie Johnson, Jody E. Johnson, Oksana Korol, J. Gordon Betts, Mark Womble

Publisher:Kelly A. Young, James A. Wise, Peter DeSaix, Dean H. Kruse, Brandon Poe, Eddie Johnson, Jody E. Johnson, Oksana Korol, J. Gordon Betts, Mark Womble

Chapter12: The Nervous System And Nervous Tissue

Section: Chapter Questions

Problem 27RQ: Which of the following voltages would most likely be measured during the relative refractory period?...

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3) You are investigating the ionic selectivity of an ion channel opened by activation of a specific group of ionotropic receptors. You use the ionic concentrations shown in the following table and determine that the reversal potential for activation of the receptors is -10 mV? Ion Intracellular (mM) Extracellular (mM) Equilibrium Potential (E1on) K+ 140 5 Na+ 10 145 Ca2+ 0.0001 2 Cl- 6. 106 a) Use the Nernst equation to calculate the equilibrium potential for each ion above. b) Is it likely that ion channel is selective to a single ion? Why or why not? c) Provide one possible ionic selectivity for this channel that could give rise to the following reversal potential. d) How would you determine if this possibility is correct?
Three currents are produced by a 56 mV depolarization leading to an action potential in a squid axon membrane during a voltage clamp experiment as shown. What is the mechanism underlying the capacitive current? 56 mV Depolarization Capacitative current Late current Early current Time (ms) Opening of Na* channels Current due to the Na/K* pump O Neutralization of the charge on the membrane Opening of K channels Membrane Membeane current imA/cm potential (mV)
1) A 100-um diameter nerve axon has the following properties: rm = 2.5 x 104 ohm x cm, ri = 1 x 105 ohm/cm, r0 = 0, cm = 3 x 10-8 F/cm. The permeability to Cl- is very high and Cl- ions are at resting potential Vm. A steady inward current is injected into the axon resulting in a Vm of -110 mV at the site of current injection. If the Vm 3 mm from the site of injection is -94.5 mV, what is the resting Vm?
atch the description with the statement that best describes the following statements hyperpolarization repolarization depolarization A. usually corresponds to opening of voltage-gated potassium channels B. any change in the membrane potential that moves the membrane potential to a value more positive than the resting potential (eg from -70mV to +35mV) C. any change in the membrane potential that moves the membrane potential to a value more negative than the resting potential (eg from -70mV to -85mV)
Please ASAP. Thank you. A hypothetical neuronal cell shows the following intracellular and extracellular concentration of sodium, potassium, calcium, and chloride ions. Extracellular concentration (mM) Intracellular concentration (mM) (Ion)out/ (Ion)inside E ion at 37 oC Sodium ion 420 60 Potassium ion 25 420 Calcium ion 16 0.4 Chloride 565 45 How does increase in the extracellular potassium concentration to 250 mM affect the Nernst potential? Why?
35.Given the following table, calculate the Resting Membrane Potential (in mV, rounded to the nearest tenths), using the GHK equation. Ion [Outside] mM [Inside] mM Relative Permeability at Rest Nernst Potential (mV) K+ 4 130 1.0 -110.2 Na+ 130 5 0.04 67.4 Cl- 75 5 0.45 -97.5
Match the description with the statement that best describes the following statements hyperpolarization repolarization depolarization A. usually corresponds to opening of voltage-gated potassium channels B. any change in the membrane potential that moves the membrane potential to a value more positive than the resting potential (eg from -70mV to +35mV) C. any change in the membrane potential that moves the membrane potential to a value more negative than the resting potential (eg from -70mV to -85mV)
2. a) sensation). the doctor decides to check the resting potential of her sensory nerves. The microelectrode is inserted and the intracellular potential is measured as -65 mv. What relative ionic concentrations are responsible for maintaining this membrane potential? A 47-year-old woman complains of paresthesis (tingling, pricking or burning a) [Na+ Jout > [Na+] in ; [K+]out > [K+]in b) [Na+ Jout > [Na+] in ; [K+]out [Ca2+]in d) [Na+ Jout [K+]in e) Active sodium potassium pump
000 Which statement does the graph illustrate? Probability of Nat channel opening 0.8 0.6 0.4 0.2 0 -80 -60 -40 -20 0 20 40 60 Membrane potential (mV) K+ moves into of the cell as the membrane depolarizes The opening of Na* channels is voltage dependent. Na+ moves out of the cell as the membrane depolarizes Tetrodotoxin blocks both microscopic and macroscopic currents.
Fill in the diagram, your illustration should demonstrate for each phase of the AP: 1. The relative concentration of K and Na 2. The relative voltage across the membrane 3. Any movement across the membrane of K and NA 4. The three kinds of channels in the membrane, and their state (open or closed) 5. Finally, indicate on the graph of the AP which phases correspond to hyper- polarization and which phases correspond to de- polarization Outside Outside Inside Inside Outside Inside Outside 1 Outside Inside Inside
The traces below show the action potential waveforms in an external meidum of different concentrations of * 40 100% 50% 33% 40 1 2 time (msec) calcium chloride potassium O sodium
Please ASAP. Thanks Ion Extracellular Concentration (mM) Intracellular Concentration (mM) Na+ 440 50 K+ 20 400 Cl- 560 52 Ca++ 10 1 What is the effect of the addition of extracellular TTX and TEA on equilibrium potential? TTX blocks K channel, and TEA blocks Na Channels. No change in the equilibrium potentail. TTX blocks Na channel and TEA blocks K Channels. The equilibrium potentials become less positive TTX blocks Na channel and TEA blocks K Channels. The equilibrium potential becomes more positive for both TTX blocks Na channel and TEA blocks K Channels. No change in the equilibrium potentail. TTX and TEA blocks Na channel. No change in the equilibrium potentail.