Membrane and Action Potentials

Question 0

Saltatory conduction is characteristic of which part of a typical neuron?

Answer 0

Axon

Question 1

_____ Diameter and ___________ cells will transmit an action potential the fastest.

Answer 1

Large diameter, Myelinated.

Question 2

A selectivity filter with carbonyl oxygens is associated with what type of ion channels?

Answer 2

Potassium

Question 4

The resting potential for typical neuron, such as a motor neuron, is best represented by what potential

Answer 4

-90 mV

Question 5

The axolemma is characterized by the presence of what?

Answer 5

voltage-gated ion channels and the ability to conduct an action potential.

Question 6

A neuron is characterized by a single ______ that is variable in length.

Answer 6

axon

Question 7

The _____ is an extension of the cell body and is typically opposite the side of the ________ where the dentrites are located.

Answer 7

axon, cell body.

Question 8

The axon is an extension of the cell body and is covered by the ____________

Answer 8

axolemma (plasma membrane)

Question 9

Diffusion potential:

Answer 9

Is caused by an ion concentration difference on either side of a membrane

Question 10

Nernst Potential

Answer 10

is the diffusion potential level across a membrane that exactly opposes the net diffusion of a particular ion through the membrane.

Question 11

Nernst Equation

Answer 11

EMF=z(61.5) x Log ([ion]outside/[ion]inside), z= valence of ion

Question 12

Voltage gated sodium channels have _____ domains and are arranged in a ________ configuration.

Answer 12

four, cylindrical

Question 13

Define Absolute refractory period:

Answer 13

Period during which a second action potential cannot be elicited even with a strong stimulus. Energy is derived directly from breakdown of ATP

Question 14

Define Relative refractory period:

Answer 14

Stronger than normal stimulus can cause action potential.

Question 15

What are factors that affect propagation speed?

Answer 15

Mylination and fiber diameter.

Question 16

Why do action potentials typically travel in the orthodromic direction?

Answer 16

b/c the signal starts at the axon hillock and the refractory period after depolarization takes a while to reset.

Question 17

What are the steps in the generation of an action potential on a neuron axon membrane?

Answer 17

Resting stage -90 mV,
depolarization stage: membrane is permeable to sodium. Replolarization stage: K+ channels open more than normal and Na+ close within a few 10,000ths of a second,
Sodium and Potassium conductance.