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Between neurons, there are two primary methods in which an impulse or action potential can reach another neuron, via a chemical and electrical synapse.
Chemical synapse
This involves a chemical messenger and the fact that both neurons are not physically connected, rather the chemical must diffuse across a synaptic cleft to pass on the message. Chemical synapses tend to be slower than electrical ones.
- The process begins with a wave of electrochemical excitation called an action potential traveling along the membrane of the presynaptic cell, until it reaches the synapse.
- The electrical depolarization of the membrane at the synapse causes channels to open that are permeable to calcium ions.
- Calcium ions flow through the presynaptic membrane, rapidly increasing the calcium concentration in the interior.
- The high calcium concentration activates a set of calcium-sensitive proteins attached to vesicles that contain a neurotransmitter chemical.
- These proteins change shape, causing the membranes of some "docked" vesicles to fuse with the membrane of the presynaptic cell, thereby opening the vesicles and dumping their neurotransmitter contents into the synaptic cleft, the narrow space between the membranes of the pre- and post-synaptic cells.
- The neurotransmitter diffuses within the cleft. Some of it escapes, but some of it binds to chemical receptor molecules located on the membrane of the postsynaptic cell.
- The binding of neurotransmitter causes the receptor molecule to be activated in some way. Several types of activation are possible, as described in more detail below. In any case, this is the key step by which the synaptic process affects the behavior of the postsynaptic cell.
- Due to thermal shaking, neurotransmitter molecules eventually break loose from the receptors and drift away.
- The neurotransmitter is either reabsorbed by the presynaptic cell, and then repackaged for future release, or else it is broken down metabolically.
This type of synapse is often found in the muscles.
Electrical synapse (a.k.a. gap junctions)
This may also involve a chemical messenger however generally they are the charged ions directly from the action potential. Additionally, the connection between different neurons are physical and direct, resulting in a generally faster connection than a chemical synapse.
- The process begins with a wave of electrochemical excitation called an action potential traveling along the membrane of the presynaptic cell, until it reaches the synapse.
- Ions directly travel through the gap junctions and into the next neuron.
This type of synapse is often found in the heart.
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What is a true statement about synapses?
The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
What is a presynaptic neuron?
a neuron from the axon terminal of which an electrical impulse is transmitted across a synaptic cleft to the cell body or one or more dendrites of a postsynaptic neuron by the release of a chemical neurotransmitter.
How is a nerve specialised to carry out its function?
A nerve cell is called a neuron. The neuron has dendrites that receive impules from the previous neuron and send it to the cell body and an axon that transmits the impulse to the next neuron. There is a space between one cell's axon and the next cell's dendrites called a synapse. Neurotransmitters are released from the axon terminal to carry the impulse across the synapse.
What is the part of the neuron that carries impulses toward the cell body?
The part of the neuron that carries impulses towards the cell body is called the dendrite.
What is the message sent down the neuron called?
What they relay is whether of not they were 'on' or 'off' and how often; and this occurs as an action potential firing frequency. There is no message in the sense that neurons might pass on complex messages, like an email for instance; or store memories of events and facts. No one neuron can do anything like that. It takes many neurons working together to achieve this.
How long does it take for an impulse to travel from one neuron to another?
one second
The junction where one neuron can transfer an impulse to another is called what?
synapse
Space where the nerve impulse jumps from one neuron to another?
Synapse
What is the space through which a nerve impulse passes from one nerve cell to another called?
A nerve impulse passes from an axon terminal of one neuron to another neuron across a synaptic gap.
How is the message caried from one neuron to another it there is a space between them?
The synaptic gap is the space between the dendrites of one neuron and the axon of the next. The impulse is carried across this space by chemicals called neurotransmitters which conduct the electrical impulse.
What is a true statement about synapses?
The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
What is A small space across which an impulse travels to move from one neuron to another?
Synapse. The gap itself is called the synapticcleft.
A small space across which an impulse travels to move from one neuron to another?
It is most definitely a synapse.
Space through which a nervous impulse is transmitted from one neuron to another?
The synaptic gap, also called the synapse.
What carries a nerve impulse from one neuron to annother?
Neurotransmitter.
Why is a neuron called an interneuron?
A neuron is called a inter-neuron because that specific neuron takes impulse from one neuron to a next neuron. For example your sensory neuron sends a impulse that you had felt a hot object. It goes through the spine to a inter-neuron to a motor neuron (this processes is called a reflex). Then the motor neuron tells your muscles in your hand to move
What is a neuron identify the parts of the neuron and their functions?
there's the axon (the nerve) the electrical impulse goes down that and covering the axon is the myelin sheath, otherwise known as a fatty sheath which insulates and helps make the electrical impulse go faster. In between each myelin sheath there are synapses (gaps between each one) and the impulse has to cross the gap so neurotransmitters are released which bind to receptors on the other side creating another electrical impulse which makes it travel even faster.
