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How Does a Message Travel Through a Neuron?
The answer to this question is actually quite complex. To understand how a message travels through a neuron, we first need to understand the structure of a neuron and how it works.
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How do neurons work?
Neurons are cells that transmit information throughout the body. They are electrically excitable, meaning they can change their membrane potential to either a positive or negative charge. This change in membrane potential is called an action potential, and it is how information is transferred from one neuron to another.
Action potentials are created by a combination of voltage-gated ion channels and ligand-gated ion channels. Voltage-gated ion channels are opened or closed in response to changes in the voltage across the cell membrane, while ligand-gated ion channels are opened or closed in response to ligands (molecules that bind to specific proteins) binding to them.
When a neuron is at rest, the voltage across its cell membrane is negative. This means that the inside of the cell is more negative than the outside. This difference in voltage is called the resting potential.
The resting potential is created by two types of ion channels: potassium leak channels and sodium leak channels. Potassium leak channels allow potassium ions (K+) to flow out of the cell, while sodium leak channels allow sodium ions (Na+) to flow into the cell. Both of these types of ion channels are always open, even at rest, but there is a higher concentration of K+ ions inside the cell than outside, so more K+ ions flow out of the cell than Na+ ions flow into it. This creates a net outward flow of positive charge and a negative resting potential.
When a neuron receives an input (a chemical signal from another neuron), ligand-gated ion channels are opened and allow Na+ ions to flow into the cell. This causes the inside of the cell to become more positive relative to the outside, and this change in voltage is called an depolarization. If enough Na+ ions enter the cell, this depolarization will reach a threshold level and trigger an action potential.
An action potential is essentially a all-or-none event: either it happens or it doesn’t. Once triggered, an action potential cannot be stopped; it will propagate down the length of the axon until it reaches the Terminal Buttons where it will trigger release of neurotransmitters into Synaptic Cleft .
How do messages travel through neurons?
There are many types of neurons, but all neurons have three basic parts: the dendrites, the cell body (or soma), and the axon. Dendrites are like tree branches; they grow out of the cell body and receive information from other neurons. The cell body contains the nucleus, which is important for the neuron to live. The axon is like a long thin wire; it carries messages away from the cell body to other neurons.
Neurons communicate with each other by sending messages through their axons. Messages travel through a neuron in the form of electrical impulses. These electrical impulses are generated by special molecules called ions. When a message comes into a neuron at one of its dendrites, it causes ions to move across the cell membrane. This movement changes the electric potential inside the cell.
If the electric potential inside the cell becomes more positive, this is called an depolarization. When an depolarization reaches a certain level, it causes an electrical impulse to travel down the axon to the next neuron. This process is called an action potential.
The role of the cell body
The cell body is the part of the neuron that contains the cell nucleus, which houses the genetic material of the neuron. The cell body also contains other important organelles, such as mitochondria and endoplasmic reticulum. The cell body is important for many functions, including protein synthesis and metabolism. The cell body is connected to the axon by a narrow region of cytoplasm called the axon hillock.
The function of dendrites
Dendrites are the branching structures that extend from the cell body of a neuron. They act as the primary site of input for the neuron, receiving impulses from other neurons or sensory cells and passing them on to the cell body. The cell body then sends an electrical impulse (or action potential) along the axon to the next neuron in the chain.
The purpose of the axon
The purpose of the axon is to transmit signals from the cell body to other neurons, muscles, or glands. Axons are usually very long and can be as thin as a human hair. The diameter of an axon can vary depending on the type of neuron it is.
The myelin sheath
The myelin sheath is a layer of insulation that surrounds the axon of a neuron. It is made up of fatty acids and lipids, and it helps to protect the axon and improve the efficiency of signal conduction. The myelin sheath is produced by oligodendrocytes in the central nervous system (CNS) and by Schwann cells in the peripheral nervous system (PNS).
The synaptic gap
In order for a message to travel from one neuron to the next, it must first cross what is called the synaptic gap. This space is between the two cells, and it is where chemical reactions take place that allow the message to be passed on.
The cell that sends the message (the presynaptic cell) releases chemicals called neurotransmitters into the synaptic gap. These chemicals then bind to receptors on the postsynaptic cell (the cell receiving the message). This binding triggers a change in the postsynaptic cell, which allows an electrical current to flow through. This current then travels down the length of the postsynaptic cell until it reaches the nucleus.
At this point, the message has been successfully passed on from one neuron to another, and it can continue its journey through the nervous system.
How electrical signals are generated
When we think, feel, or move, our cells must generate electrical signals. This is how our nervous system communicates. But how do these signals get generated?
It all starts with our cells. Inside every cell is a nucleus, which contains our DNA. That DNA instructs the cell to create proteins, which are the building blocks of our bodies. Those proteins might be enzymes that help chemical reactions happen, or they might be structural proteins that give our cells shape.
But some proteins have a more specialised job: they act as receptors. Receptors are like docking stations for chemical messages that tell the cell what to do. These messages can be hormones circulating in our blood, or neurotransmitters released by other neurons.
When a message binds to its receptor, it triggers a change in the receptor protein. That change sets off a chain reaction, causing different molecules inside the cell to move around. Eventually, this chain reaction leads to the cell generating an electrical signal.
This electrical signal travels along the cell’s membrane and is then passed on to neighbouring cells through gap junctions. Gap junctions are places where the membranes of two cells touch, allowing electrical signals to pass from one cell to another. This is how an electrical signal can travel along a neuron, from the dendrites all the way to the axon terminal!
How chemical signals are transmitted
Neurons are cells that transmit chemical and electrical signals throughout the nervous system. They are responsible for everything from processing sensory information to coordinating muscle movement.
Each neuron has a cell body, which contains the nucleus, and a long, slender nerve fiber called an axon. The axon is surrounded by alayer of insulating material called myelin, which helps to protect the nerve fiber and speed up signal transmission.
At the end of the axon is a small gap called a synapse. This is where signals are transmitted from one neuron to another. When an electrical signal reaches the synapse, it triggers the release of chemical messengers (neurotransmitters) into the gap. These chemicals then bind to receptors on the other side of the synapse, causing a change in the electrical state of the second neuron. This change in electrical state can either excite or inhibit further signal transmission.
The role of neurotransmitters
Neurotransmitters are chemicals that allow neurons to communicate with each other. They are produced by the neuron and stored in tiny sacs called vesicles. When the neuron is stimulated, the vesicles release the neurotransmitters into the synapse, a tiny gap between neurons. The neurotransmitters then bind to receptors on the next neuron, and this triggers a change in the electrical potential of that neuron. This change in electrical potential is what allows neurons to communicate with each other and ultimately send messages throughout the body.
