12. (a) Using Eq. AQ=CAV and the data in the Table, calculate the number of ions entering the axon duringthe action potential, per meter of nonmyelinated axon length. (The charge on the ion is 1.6 x 10-19 coulomb.)(b) During the resting state of the axon, typical concentrations of sodium and potassium ions inside the axonare 15 and 150 millimole/liter, respectively. From the data in the Table, calculate the number of ions permeter length of the axon.Table 13.1 Properties of Sample AxonsHint:1 F (farad) = 1coulomb/1 voltPropertyNonmyelinated axonMyelinated axonAxon radius5 x 10-m5 x 10-6 m1 mole /liter = 6.02 x 1020 particles (ions, atoms, etc. ) Resistance per unit length of fluidcm6.37 x 10°2/m6.37 x 10°2/mboth inside and outside axon (r)Conductivity per unit length ofaxon membrane (gm)1.25 x 10-4 mho/mIn the resting state, the axon voltage is -70mV.During the pulse, the voltage changes to about+30mV, resulting in a net voltage change acrossthe membrane of 100 mV. Therefore, V to be usedin the equation AQ=CAV is 100 mV.3 x 10-7 mho/mCapacitance per unit length of3 x 10-7 F/m8 x 10-10 F/maxon (c)

12. (a) Using Eq. AQ=CAV and the data in the Table, calculate the number of ions entering the axon during the action potential, per meter of nonmyelinated axon length. (The charge on the ion is 1.6 x 10-19 Coulomb.) (b) During the resting state of the axon, typical concentrations of sodium and potassium ions inside the axon are 15 and 150 millimole/liter, respectively. From the data in the Table, calculate the number of ions per meter length of the axon. Axonc

12. (a) Using Eq. AQ=CAV and the data in the Table, calculate the number of ions entering the axon during the action potential, per meter of nonmyelinated axon length. (The charge on the ion is 1.6 x 10-19 Coulomb.) (b) During the resting state of the axon, typical concentrations of sodium and potassium ions inside the axon are 15 and 150 millimole/liter, respectively. From the data in the Table, calculate the number of ions per meter length of the axon. Axonc

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter12: Fluid Dynamics And Its Biological And Medical Applications

Section: Chapter Questions

Problem 64PE: Oxygen reaches the veinless cornea of the eye by diffusing through its tear layer, which is 0.500-mm...

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Assume an axon has the same characteristics as the class example except the radius of the axon is 0.005 mm and the membrane thickness is 20.0 nm. The percentage fractional change in the concentration of Na+ ions in the axon during one action potential is %? Record the answer to the nearest one thousandth.
What is the magnitude of the electric field across an axon membrane 1.2×10−8 m thick if the resting potential is -70 mV ?
The velocity of spike propagation is proportional to the following combination of factors: 1 a C, V R„R, m Where a is the radius of the axon, Rm and R; are specific resistances of the membrane and the internal buffer, respectively. If we double the radius and simultaneously increase the concentration of salt inside the axon twice (i.e. R; decreases two times), by how many fold will the velocity change?
a) What was the smallest voltage required to produce a contraction (the threshold voltage)? What proportion of the fibers in the muscle do you think were contracting to produce this small response? b) What was the smallest voltage required to produce the maximum (largest) contraction? What proportion of the fibers in the muscle do you think were contracting to produce this maximal response?
What is the magnitude of the electric field in unite of N/C across an axon membrane (1.00x10^0)x10-8 m thick if the resting potential is -(7.400x10^1) mV?
a) How does voltage change over distance from the stimulator on the artificial axon? AND why does this occur? (Think: where is the current going?) b) How and why are neurons affected by the addition of myelin (think membrane resistance, capacitance, and the length constant)?
What is the resistance of a 2.0 - mm long axon?
Question 7 50 40 40 Peak action potential Depolarization Repolarization 0.2/0.5 points Membrane potential (mV) 0 - Threshold of excitation -50 Initial stimulus -70 resting hyperpolarization resting return to resting -100 When are voltage gated Na+ channels closed (and inactivated)? The different ranges provided start at resting, go through an AP, and end at resting. (-70mV to -50mV) (-50mV to +40mV) (+40mV to -70mV) (-70mV to -80mV) (-80mV to -70mV)
(III) During an action potential, Na* ions move into the cell at a rate of about 3 × 10-7 mol/m² - s. How much power must be produced by the "active Na* pumping" system to produce this flow against a +30-mV potential difference? Assume that the axon is 10 cm long and 20 µm in diameter.
What is the resistance of the of an axon’s axoplasm segment with a length of 1 mm (enter your answer in units of M Ω)?
Find the radius of the unmyelinated axon (m) with space parameter A = 14 mm, (Resistance of a unit area of the membrane, Rm =0.2 Q.m², Resistivity of axoplasm, p, =2 Q.m). A. 0.00392 B. 0.01568 C. None D. 0.02352 E. 0.00784
Peripheral (vascular) resistance is (A) directly proportional to the length of the vessel (B) directly proportional to the viscosity of the blood (C) inversely proportional to the radius to the fourth power (D) A and B (E) all of the above