Neuron Synapse

greatpacificmedia

24 Oct 200903:19

Summary

TLDRThis script explains the process of synaptic transmission in neurons. When an action potential reaches the synaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. These chemicals bind to receptors on the post-synaptic neuron, opening ion channels and causing either excitatory (EPSP) or inhibitory (IPSP) post-synaptic potentials. These potentials, which determine neuronal firing, are short-range and typically dissipate after a few millimeters, but they can influence the neuron's decision to generate an action potential.

Takeaways

🧠 The synapse is a junction where two neurons come close but do not touch, separated by a synaptic cleft.
⚡️ An action potential reaching the synaptic terminal causes it to release neurotransmitters into the synaptic cleft.
🔄 Neurotransmitters diffuse across the cleft and bind to specific receptors on the post-synaptic neuron.
🔗 Each receptor type binds to a specific neurotransmitter, triggering the opening of ion channels in the post-synaptic membrane.
💧 The opening of ion channels allows ions to flow into the post-synaptic neuron, creating a post-synaptic potential (PSP).
🌐 Depending on the ion channels opened, PSPs can be excitatory (EPSP) or inhibitory (IPSP), affecting the neuron's likelihood to fire an action potential.
🚦 Excitatory synapses lead to EPSPs, making the neuron more likely to fire, while inhibitory synapses lead to IPSPs, making it less likely.
🚫 Post-synaptic potentials are short-lived, as ions leak back across the membrane, causing the signal to dissipate after a few millimeters.
🏃 PSPs travel to the cell body where they accumulate and determine if an action potential will be generated.
🎵 The script is accompanied by music, suggesting it is part of an educational video aiming to engage the viewer.

Q & A

What is a synapse and what is its function?
-A synapse is a minuscule gap that separates the synaptic terminal of the first neuron from the dendrite or cell body of the second neuron. Its function is to facilitate the transmission of signals from one neuron to another without direct contact.
How does an action potential reaching the synaptic terminal affect the neuron?
-When an action potential reaches the synaptic terminal, it causes the terminal to become positively charged, which triggers the release of neurotransmitters into the synaptic cleft.
What role do neurotransmitters play in the synaptic transmission?
-Neurotransmitters diffuse across the synaptic cleft and bind to specific receptors on the post-synaptic neuron, causing ion channels to open and allowing ions to flow across the cell membrane.
What are the two types of post-synaptic potentials and what do they do?
-There are two types of post-synaptic potentials: excitatory post-synaptic potentials (EPSPs) and inhibitory post-synaptic potentials (IPSPs). EPSPs make a neuron more likely to fire an action potential by making it less negative inside, while IPSPs make it less likely by making it more negative.
What is the difference between an excitatory and an inhibitory synapse?
-An excitatory synapse produces EPSPs, enhancing the likelihood of the post-synaptic neuron firing an action potential. An inhibitory synapse produces IPSPs, reducing the likelihood of the post-synaptic neuron firing an action potential.
How do the specific types of receptors in the post-synaptic membrane contribute to the synaptic transmission?
-Each type of receptor in the post-synaptic membrane binds to a specific type of neurotransmitter, ensuring that the appropriate response is triggered in the post-synaptic neuron.
What happens to the ions that flow into the post-synaptic neuron?
-The ions flow into the post-synaptic neuron along their concentration gradients, creating a post-synaptic potential. However, they eventually leak back across the membrane, and the signal is lost after traveling a short distance.
Why can't post-synaptic potentials travel far in a neuron?
-Post-synaptic potentials cannot travel far because the ions that cause them leak back across the membrane, dissipating the signal after a few millimeters at most.
How do post-synaptic potentials contribute to the generation of an action potential in the cell body?
-Post-synaptic potentials, although they do not travel far, can reach the cell body where they accumulate and determine whether the cell body will produce an action potential.
What is the significance of the concentration gradients in the flow of ions across the cell membrane?
-The concentration gradients drive the flow of ions into or out of the post-synaptic neuron, which is essential for the generation of post-synaptic potentials that influence the neuron's excitability.

Outlines

00:00

🧠 Neurotransmission at the Synapse

This paragraph explains the process of neurotransmission at the synapse. When an action potential reaches the synaptic terminal of an axon, it encounters a synapse, a region where two neurons are close but not touching. A tiny gap called the synaptic cleft separates the pre-synaptic neuron's terminal from the post-synaptic neuron's dendrite or cell body. The arrival of the action potential causes the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to specific receptors on the post-synaptic neuron, triggering the opening of ion channels and the flow of ions. This flow of ions creates a post-synaptic potential, which can be either excitatory (EPSP), making the neuron more likely to fire an action potential, or inhibitory (IPSP), making it less likely. Synapses are classified as excitatory or inhibitory based on the type of post-synaptic potential they produce. Post-synaptic potentials are limited in their travel distance within a neuron but can reach the cell body to influence whether an action potential is generated.

Mindmap

Keywords

💡Action Potential

An action potential is a brief and rapid change in the electrical potential across the membrane of a neuron. It is the mechanism by which neurons transmit information to one another. In the video, the action potential is described as reaching the synaptic terminal of the axon, which initiates the process of communication between neurons.

💡Synapse

A synapse is a junction between two neurons where information is passed from one to the other. It consists of a small gap across which signals are transmitted chemically. The video script explains that when an action potential reaches the synaptic terminal, it encounters the synapse, where neurotransmitters are released into the synaptic cleft.

💡Synaptic Terminal

The synaptic terminal is the end part of an axon where it communicates with another neuron. It is responsible for releasing neurotransmitters into the synaptic cleft. The script describes how the arrival of an action potential at the synaptic terminal causes it to become positively charged and release neurotransmitters.

💡Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals across a synapse from one neuron to another. They play a crucial role in the communication between neurons. The video mentions that the synaptic terminal releases neurotransmitters into the synaptic cleft upon the arrival of an action potential.

💡Synaptic Cleft

The synaptic cleft is the minuscule gap between the synaptic terminal of one neuron and the dendrite or cell body of another. It is where neurotransmitters diffuse across to bind with receptors on the post-synaptic neuron. The script describes the synaptic cleft as the area where neurotransmitters diffuse rapidly and bind to receptors.

💡Dendrites

Dendrites are branched extensions of a neuron that receive signals from other neurons. They are equipped with receptors that can bind to specific neurotransmitters. In the video, dendrites are mentioned as part of the post-synaptic neuron where neurotransmitters bind to their receptors.

💡Post-Synaptic Neuron

The post-synaptic neuron is the neuron that receives the signal from the pre-synaptic neuron across the synapse. It has receptors that bind to specific neurotransmitters, leading to changes in its electrical potential. The video script explains how the post-synaptic neuron responds to neurotransmitters by generating either excitatory or inhibitory post-synaptic potentials.

💡Excitatory Post-Synaptic Potential (EPSP)

An EPSP is a change in the membrane potential of a post-synaptic neuron that makes it more likely to generate an action potential. It is caused by the opening of ion channels that allow positively charged ions to flow into the neuron. The video describes EPSPs as resulting from the binding of neurotransmitters to their receptors on the post-synaptic membrane.

💡Inhibitory Post-Synaptic Potential (IPSP)

An IPSP is a change in the membrane potential of a post-synaptic neuron that makes it less likely to generate an action potential. It is caused by the opening of ion channels that allow negatively charged ions to flow into the neuron or positively charged ions to flow out. The video script contrasts IPSPs with EPSPs, explaining that they make the neuron more negative inside.

💡Excitatory Synapse

An excitatory synapse is a type of synapse that, when activated, increases the likelihood that the post-synaptic neuron will generate an action potential. This is due to the release of neurotransmitters that cause EPSPs. The video script mentions that synapses producing EPSPs in the post-synaptic cell are called excitatory synapses.

💡Inhibitory Synapse

An inhibitory synapse is a type of synapse that, when activated, decreases the likelihood that the post-synaptic neuron will generate an action potential. This is due to the release of neurotransmitters that cause IPSPs. The video script explains that synapses producing IPSPs are called inhibitory synapses.

💡Ion Channels

Ion channels are proteins embedded in the cell membrane that allow specific ions to pass through. They play a critical role in the generation of action potentials and post-synaptic potentials. The video script describes how the binding of neurotransmitters to receptors can cause specific types of ion channels to open, leading to the flow of ions across the cell membrane.

Highlights

An action potential reaching the synaptic terminal of the axon encounters a synapse, where neurons come close but do not touch.

A minuscule gap called a synaptic cleft separates the pre-synaptic neuron from the post-synaptic neuron.

The arrival of an action potential at the synaptic terminal causes it to become positively charged.

Neurotransmitters are released into the synaptic cleft in response to the action potential.

Neurotransmitters diffuse rapidly across the synaptic cleft and bind to receptors in the post-synaptic neuron.

Each type of receptor binds to a specific type of neurotransmitter.

Binding of neurotransmitters to receptors causes specific ion channels in the post-synaptic membrane to open.

Ions flow across the cell membrane of the post-synaptic neuron along their concentration gradients.

The flow of ions into the post-synaptic neuron causes a post-synaptic potential.

Synaptic potentials can be excitatory (EPSP) or inhibitory (IPSP), depending on the ion channels and ions involved.

An excitatory synapse produces EPSPs in the post-synaptic cell.

An inhibitory synapse produces IPSPs, making the neuron less likely to fire an action potential.

Post-synaptic potentials cannot travel far in a neuron, typically dissipating after a few millimeters.

Post-synaptic potentials reach the cell body where they determine whether an action potential will be produced.

The process of neurotransmission is crucial for communication between neurons.

The synaptic cleft plays a critical role in the transmission of signals between neurons.

The specificity of neurotransmitter-receptor interactions ensures precise communication in the nervous system.

The balance between excitatory and inhibitory signals is essential for proper neuronal function.