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The axon is a very long extension of the neuron. The way in which an electrical current can pass involves the inside and outside of the cell membrane.
Action potentials
The stage is set with potassium and sodium cations, which all repel one another. The cations would have been in equilibrium, but pumps powered by ATP keep messing the equilibrium up, pumping potassium into the cell and sodium out. The cations then flow back through K/Na protein channels, but there happens to be more K channels. Because the pump is faster than the channels, there is an electrical charge due to the excessive amount of repulsion outside the cell with all the incoming K cations, a difference of -70 millivolts.
An action potential is set off from a resting potential by a change of voltage when a neuron senses something. The voltage change happens because after something is sensed more Na channels open up. If the sense is intense enough, then depolarization (voltage drops to -50 mV) occurs. If not, nothing happens. After depolarization, even more Na channels open, reaching the action potential.
Transmitting the Signal
Na channels further along the axon open, creating action potentials there while K channels in the first region open to reach resting potential again. Meanwhile, the action potentials set off more reactions down the axon as they become resting potentials again, undergoing electrically unbalanced diffusion and recreating the voltage of -70 mV.
Wiki User
∙ 13y ago
Wiki User
∙ 14y agowell,
1. the membrane starts in its resting state-POLARISED! with the inside of the cell being -60mV compared to the outside.
2. the membrane DEPOLARISES!
3. POTASSIUM IONS DIFFUSE OUT OF THE CELL BRINGING THE P.D BACK TO NEGATIVE INSIDE COMPARED WITH THE OUTSIDE!!!!!!!!!!!-VERY IMPORTANT-RE-POLARISATION!!!!!!!
4. sodium ion channels close and potassium channels OPEN!
5. this creates local currents in the cytoplasm of the neurone
HOPE THIS HELPS!
Wiki User
∙ 6y agoWiki User
∙ 12y agoAction Potental.. hahaha i cant spell but i think that's what it is
Wiki User
∙ 13y agoNerve impulses travel along an axon.
A nerve impulse along an axon is an Electrical (electrochemical) Signal, called an action potential.
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When signals come into the soma from the many dendrites they are added together. When the sum of these signals reaches a critical point a signal is fired down the axon. When it reaches the end of the?
threshold
What is the junction between the axon of one nerve cell and the dendrite of another nerve cell?
No, not at all. The axon is the transmitting end of a neuron, and a dendrite is the receiving beginning of another neuron.The axon sends its signal "through" a synapse between the axon terminal and a dendrite via chemicals called neurotransmitters that it releases into the synaptic space, which diffuse to and are taken into structures on dendrites called ligand-gated ion pores, which open to allow sodium ions into the dendrite, which change its electrical charge, which initiates the propagation of a corresponding signal along the dendrite and cell body toward the axon hillock, which, if enough signals from dendrites reach it, will then fire and send the nerve signal onward along the axon, as an action potential.
An electrical impulse moving down an axon is called what?
The nerve that travels down a neuron axon is basically Action Potential.It is an electrochemical change that passes through the cell.
Are action potential and local potential reversible?
Under normal circumstances action potential will proceed unilaterally. An action potential cannot proceed down an axon and depolarize in the reverse direction on the same axon. It must carry information on one axon in one direction and then on another axon in a separate direction. In a lab you can depolarize neurons in the middle of an axon and it will depolarize bilaterally.
Do blood cells move from the axon terminal to the dendrites?
Technically a neural impulse moves from the cell body to the axon terminal, because a nerve impulse is defined as an electrical signal that travels along an AXON.This may be confusing because neural signals move in three places with respect to the neurons, in three correspondingly different ways, and only one is called the neural impulse.Neural signals move in these places: betweenneurons (ie, from one neuron to another), intoneurons, and along axons (the outputs of neurons, when a neuron has fired).BETWEEN NEURONS: A neural signal can be passed from one neuron to another, at a synapse, across the synaptic cleft, by the release of chemicals called neurotransmittersfrom the presynaptic neuron, which diffuse across the synaptic cleft, to fit into receptors on the postsynaptic neuron. This is a chemical transmission of the neural signal, not an impulse.INTO A NEURON: when a signal has passed from one neuron to another by the release, diffusion, and reception of neurotransmitters, it initiates a graded response in the dendrites of the postsynaptic neuron, which travels with decreasing strength down the dendrites and across the soma (cell body), until it reaches the root of the axon, the axon hillock. This graded response is also not an impulse.ALONG THE AXON: if enough graded response signalsreach the axon hillock at about the same time, (it might be helpful to think of them as degraded signals, since they get weaker the further they travel), such that their combined strengths can trigger an all or nothing action potential in the axon, then it can be said that the neuron has fired a neuronal impulse.So, there are neural signals which move betweenneurons and into neurons, and neural impulses which fire and move along axons from the cell body (soma).
What is action portential?
The most common type of action potential is the change in voltage down the axon of a neuron. In other words, it is an electrical signal that is sent down the axon of a nerve cell.
What does an action potential refer to as?
An action potential is basically the message which is sent by the neuron down the axon towards synapse.In other words it is the impulse or the electrical signal that travels along the axon due to difference in the positive and negative charges inside and outside of the axon wall.
What is the function of the axon hillock?
An axon hillock is part of a neuron that acts as a bridge between the cell body and the axon. Electrical impulses from the dendrites and cell body are summed at this point, which is then sent down the axon.
What does a dendrite do in a nerve cell do?
It recieves the chemical signal from the terminal branches of a nearby neuron and sends it down the axon
When a neuron is depolarized to threshold?
1. The neuron fires an action potential, sending the electrical signal down the axon.
What speeds up the passage of electrical messages by acting as a insulator of the neuronal signal?
The Myelin Sheath that surrounds the axon insulates the axon but also increases the speed of the message traveling down it.
Do small unmyelinated axon travel signal faster than large unmyelinated axon?
no
How does an axon release neurostransmitter?
An axon sends signal from dendrites to terminals to release neurotransmitters
What are the components of a function?
The dendritic tree (to bind neurotransmitters (NTs)), the soma (also referred to as the cell body), the axon hillock (where action-potentials initiate), the axon (propagates the electrical signal), and the axon terminal (release of neurotransmitters). The membrane properties are also different to the average cell because they contain receptors and a high density of ion channels. Inside the cell, NTs are synthesized and 'shipped' down the axon to the axon terminal on long thin filaments propelled by tiny actin/dynein 'motors'. Once at the terminal, the NTs wait at the 'presynaptic active zone' for release (which is prompted by the electrical signal conveyed down the axon from the axon hillock).
What are the components of a neuron?
The dendritic tree (to bind neurotransmitters (NTs)), the soma (also referred to as the cell body), the axon hillock (where action-potentials initiate), the axon (propagates the electrical signal), and the axon terminal (release of neurotransmitters). The membrane properties are also different to the average cell because they contain receptors and a high density of ion channels. Inside the cell, NTs are synthesized and 'shipped' down the axon to the axon terminal on long thin filaments propelled by tiny actin/dynein 'motors'. Once at the terminal, the NTs wait at the 'presynaptic active zone' for release (which is prompted by the electrical signal conveyed down the axon from the axon hillock).
What signal travels along the axon?
The high-speed signals that pass along the axon are called action potentials. They spread in a wave of depolarization.
How does a signal cross from the axon of the neuron to the receiving cell?
When the electrical signal reaches the end of an axon, neurotransmitters are released. They travel across the synapse. Once they reach the receiving cell, they create a new electrical signal.
