Which phenomenon explains the unidirectional propagation of...

Name: which phenomenon explains the unidirectional propagation of action potentials question 10select one a the voltage dependence of the sodium channels cross out b the voltage dependence of the 27668
Uploaded: 2021-08-14T13:12:42-08:00
Duration: 2 min 54 s
Channel: Joanna Quigley
Description: which phenomenon explains the unidirectional propagation of action potentials question 10select one a the voltage dependence of the sodium channels cross out b the voltage dependence of the 27668

Which phenomenon explains the unidirectional propagation of action potentials? Question 10Select one: a. The voltage dependence of the sodium channels cross out b. The voltage dependence of the potassium channels cross out c. The presence of a refractory period at a location where an action potential has just passed cross out d. Sufficient “leakiness” of the axons, such that backward propagation of action potentials is prevented cross out e. The polarized orientation of microtubules within the axon cross out Clear my choice

Transcript

00:01 Which of these does not contribute to propagation? is it a, as the area outside the membrane becomes negative, it attracts ions from adjacent regions.

00:12 As the inside becomes positive, it attracts negative ions from the neocytoplasm, depolarising nearby regions of the membrane.

00:20 B, the refractory period allows the impulse to travel in one direction only.

00:26 C, each segment prevents the adjacent segments from firing.

00:31 D, the magnitude of the action potential, stays the same as it travels down the axon, or e, up to a limit, increasing the intensity of stimulus increases the number of action potentials.

00:43 Okay, so propagation.

00:45 We have a neuron.

00:48 There's the cell body, and here is the axon, and at the end we have the synapse.

00:57 So give it some dendrites as well.

01:02 There we go.

01:03 So the action potential travels down the axon.

01:08 Which of these helps contribute to this propagation? so if we have a look at b, this prevents any backflow.

01:20 So this is important because if we also look at e, we can see that we can get an increase in the number of action potentials.

01:26 They can come more frequently.

01:28 But if there were no refractory period, and we got...

01:32 Movement back up, that would interfere with the propagation of multiple action potentials.

01:38 So b is important.

01:40 And e similarly is important...

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