Electrical Signals in Neurons: Ion Channels (Nursing)

00:01 So now that we've gone through many of the structures found in the nervous system, let's start talking about some of the functions.

00:08 Let's take a look at how we're going to generate nerve impulses.

00:13 In order for a nerve impulse to occur, excitable cells must communicate with each other via action potentials or graded potentials.

00:25 Action potentials are going to allow for communication over both short and long distances while graded potentials are going to only allow communication over short distances.

00:38 The production of both action potentials or graded potentials are going to depend upon the existence of a resting membrane potential as well as the existence of certain ion channels. Let's take a look at those channels.

00:56 There are four different types of channels that are found in the plasma membrane of neurons.

01:03 These channels are going to play a role in an action potential, a graded potential, as well as establishing a resting membrane potential.

01:14 These channels include leakage channels, ligand-gated channels, mechanically gated channels, and finally, voltage-gated channels.

01:29 The first of these channels is going to be the leakage channels.

01:35 Leakage channels such as potassium leakage channels found in the plasma membrane of neurons are going to cause certain ions to leak from or into the cell.

01:48 These are going to randomly open at different times.

01:52 The second type of channel is going to be ligand-gated channels.

01:57 Ligand-gated channels are going to respond to a chemical stimulus such as a ligand binding to its receptor.

02:06 An example of ligand-gated channels are the acetylcholine binding to channels which are gonna be necessary for nerve impulse to happen.

02:16 A third type of channel is the mechanically gated channels.

02:21 These are going to respond to a physical stimulus so something physically moving them such as vibration or pressure.

02:30 In our ears, we have these mechanically gated channels which actually respond to the vibrations from sound waves.

02:39 And finally, we have the voltage-gated channels.

02:43 We've seen these before in the muscular system.

02:47 These are going to respond to a change in the voltage across the membrane of the neuron.