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Synaptic Transmission
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Biopsychology – The Nervous and Endocrine Systems
In this course, Mr Kevin Silber (University of Derby) discusses the functions of the nervous system and the endocrine system. In the first lecture, we think about the role of neurons and the process of synaptic transmission. In the second lecture, we think about different types of neurotransmitters. In the third lecture, we think about the impact of recreational drugs on the brain. Next, we turn to the endocrine system and discuss how the different hormones produced by our endocrine glands are used to regulate bodily functions and processes. In the fifth and final lecture, we look at how the nervous system and the endocrine system work together to produce the ‘fight or flight’ response when our body is confronted with a threat.
Synaptic Transmission
In this lecture, we think about the process of synaptic transmission, focusing in particular on: (i) how nerve cells or ‘neurons’ are structured; (ii) how information is transmitted between neurons through electrical and chemical signals; (iii) the role of neurotransmitters in relaying chemical information at the synapse; (iv) how this may have either an excitatory or inhibitory effect on the next neuron.
Hi.
00:00:05My name is Kevin Silver,
00:00:06and I'm a senior lecturer in psychology at the University of Derby.
00:00:07In this module, we're going to look at synaptic transmission. In a previous course.
00:00:12I've talked about the structure of the neuron
00:00:17and have mentioned that the output side of a neuron
00:00:20is the axe on that ends in a terminal bootle,
00:00:24that terminal Bhutan, together with the gap that is after the terminal, Bhutan
00:00:28and the dendritic area of the next neuron.
00:00:35Together, those three elements make up what we referred to as the synapse.
00:00:39Now, interestingly,
00:00:44the way in which information is communicated
00:00:47along a neuron is pretty much electrical.
00:00:50But transmission between the neuron and
00:00:54whatever follows next be that another neuron
00:00:58or muscle or a gland is a chemical way of conveying information.
00:01:01So in the terminal Bhutan,
00:01:09we see as you can see in the diagram we see vehicles.
00:01:11These are sacks that are filled with a substance called neuro transmitter.
00:01:16We'll talk about neurotransmitters
00:01:22in another module. In this course,
00:01:24these are special chemicals that will act as the messengers
00:01:28from the neuron to whatever follows next for simplicity.
00:01:33I'm going to assume now for the rest of this that what follows next is another neuron.
00:01:38So these vehicles hold the neurotransmitter substance until an action potential.
00:01:44An electrical signal
00:01:51comes down the axon,
00:01:54telling the neuron that it is time to release this neurotransmitter substance.
00:01:56When that happens, the vehicles migrate to the very tip of the terminal Bhutan.
00:02:02And there they fuse with the membrane of the terminal Bhutan.
00:02:10And in so doing, they spill their contents
00:02:14into the synaptic cleft.
00:02:18And this process we call Exocet psychosis.
00:02:21Now, once in the synaptic cleft,
00:02:25these neurotransmitter molecules are free to just
00:02:29float around in any particular direction.
00:02:33Biophysics process called Brownie in motion.
00:02:36Some of them, though,
00:02:39will go in the direction of the dendrite of the next neuron.
00:02:41Now, on the dendrites of these next neuron,
00:02:46there are
00:02:51ion channels. That is, channels that will let particular iron chemicals through
00:02:52and attached to those iron channels is what we call a receptor.
00:02:59These receptors are specific to specific types of neuro transmitter,
00:03:04so there's not just one kind of neurotransmitter in the brain.
00:03:10There are lots of different ones,
00:03:14So the neurotransmitter that is released from the synaptic terminal, Bhutan,
00:03:17into the synapse
00:03:23some of those molecules will make their way across the synapse
00:03:25and will attach themselves to the receptor on the dendrite,
00:03:30the other side.
00:03:34Now this can be best thought of as a kind of lock and key mechanism.
00:03:37So the lock, which is the receptor,
00:03:41is only activated by a certain type of neuro transmitter,
00:03:45which we can imagine as the key.
00:03:49And when that happens,
00:03:53the ion channel that is attached to that
00:03:56receptor in the membrane of the receiving neuron
00:03:59will open that channel will open
00:04:04and ions chemicals, usually for neurons either sodium ions or potassium ions,
00:04:07can then flow in or out of the neurons.
00:04:15Now, why does any of this happen? Well, because
00:04:19the idea is to either make or prevent the next neuron
00:04:23from itself, firing an action potential.
00:04:30In some circumstances,
00:04:33the action is to try and help the next neuron to fire its own action potential,
00:04:36and we call this process excitation.
00:04:43In other words, it excites
00:04:47the next neuron,
00:04:49but in other cases,
00:04:52the process is actually designed to try and stop the next neuron from firing.
00:04:54In that case, we call it this a process of inhibition.
00:05:02Now, if you imagine that actually,
00:05:09where a synapse exists is a tiny minute portion of the whole of the next neuron.
00:05:12Imagine that you're a single person
00:05:24sitting in a massive stadium.
00:05:27That's one of these synapses.
00:05:30And imagine, then that one entrance
00:05:34to the stadium
00:05:37is where we have to collect
00:05:39enough charge
00:05:41to enough of an excitation
00:05:44to have an action potential fire in that next year on.
00:05:46So these are hundreds of thousands of tiny contributions,
00:05:51and if we think of it in those ways and we consider excitation and inhibition,
00:05:57we can see that some signals will be excitatory.
00:06:02In other words, they'll be trying to get that next neuron to fire,
00:06:07and some will be inhibitory.
00:06:12They'll be trying to prevent that next neuron from firing
00:06:14and at that special position
00:06:18where I've called the entrance particular entrance in the stadium.
00:06:20But actual name is the Axon hillock.
00:06:24If there is enough excitation
00:06:28as a balance from the excitation and inhibition that's happened all over the place,
00:06:32if there's enough excitation at that point,
00:06:38then that knew that next neuron will itself fire an action potential.
00:06:40So in this way, synaptic transmission
00:06:46is a way of getting the message across to the next neuron,
00:06:49but allowing that all of the thousands of messages coming into that neuron
00:06:54have a balance point, some being excitatory, some being inhibitory,
00:06:59all trying to exert their influence a little bit on whether the next neuron fires.
00:07:05
Cite this Lecture
APA style
Silber, K. (2020, January 30). Biopsychology – The Nervous and Endocrine Systems - Synaptic Transmission [Video]. MASSOLIT. https://massolit.io/courses/the-nervous-system-and-the-endocrine-system/synaptic-transmission
MLA style
Silber, K. "Biopsychology – The Nervous and Endocrine Systems – Synaptic Transmission." MASSOLIT, uploaded by MASSOLIT, 30 Jan 2020, https://massolit.io/courses/the-nervous-system-and-the-endocrine-system/synaptic-transmission