How do impulses travel throughout the nervous system?

Answer 1

An impulse travels from one nerve to another by release & subsequent diffusion of chemicals called neurotransmitters across a very small gap between neurons, called a synapse.

How neurotransmitters are released: As an impulse reaches an end of a neuron (the axon terminal), the impulse opens ion pores in that axon terminal which allows Calcium ions to enter, which cause the movement of small membrane bounded packets of neurotransmitter chemicals, called vesicles (like tiny water balloons), to move to the cell membrane, where the vesicles fuse into the cell membrane, thus releasing the contents, the neurotransmitters, into the small space (the synaptic cleft) between the axon terminal and the dendrite of the post-synaptic neuron (the neuron the impulse is traveling to).

What neurotransmitters do when they reach the post-synaptic neuron: The post-synaptic neuron has many receptor structures each of which are like a combination of a "well", and an open-and-closeable tunnel or pore. The "well" (or hole with a bottom surface) is a RECEPTOR for the neurotransmitter chemical, in that the neurotransmitter FITS into that well like a key into a lock. And when a neurotransmitter diffuses to and enters that well, it affects the shape of the companion tunnel (ION PORE), such that the ion pore OPENS, thus allowing Sodium ions to enter the post-synaptic neuron (normally at a dendrite, the manifold tiny input structures for a neuron).

A previous answer slightly improved: Nerve impulse traveling

The impulse is like an electrical current which 'flows' along the nerves cells, their inputs ('branches' called dendrites), their outputs (axons), and the junctions between nerves; but it is not so simple as a regular electrical wire, because a complex biochemical process is also involved. This process is responsible for the initial creation of the electrical current, to its re-creation some additional times along its passing (- otherwise it would have died out because of the long lengths such an impulse travels), and to its re-creation in any 'new' nerve cell it reaches.

Answer 2

At the end of an axon of a neuron (the long part of the nerve going to a dendrite of another neuron), there is a small gap between the axon and the dendrite. This gap is called a synapse. If an impulse is going from axon --> dendrite, then this is what happens:

1. calcium ions are pumped into the end of the axon. This causes the vesicles in the end of the neuron to go towards the synapse.
2. Inside the vesicles are neurotransmitters, which will stimulate an impulse in the next neuron. When the vesicle reaches the edge of the axon, it releases the neurotransmitters into the synapse.
3. The neurotrasmitters diffuse across the synapse
4. receptors on the dendrite get the neurotransmitters, and in response start another impulse in the next neuron.

It's a bit confusing at first (maybe)! You can search on this on Google, and I'm sure some worksheet information page will come up or something, with pictures!

Answer 3

neural impulses move from DENDRITES, across the SOMA, and down the AXON to a SYNAPSE.

The neural impulses move by ELECTRO-CHEMICAL actions:
when an impulse arrives at a dendrite (by neurotransmitter CHEMICALS being released into a SYNAPSE at the dendrite), pores in the dendrite are caused to open, allowing sodium IONS (ions have an ELECTRIC charge) into the dendrite; these electrically charged molecules repel or push one another down the dendrite and across the soma (this process is called ELECTROTONIC CONDUCTION) until they accumulate at the beginning of the axon (the axon HILLOCK), where, if enough ions have accumulated to raise the voltage sufficiently, that voltage causes voltage-gated ion pores to open, which allows sodium ions to enter the axon, which causes adjacent pores on the axon to open, allowing more sodium ions to enter, opening more pores further along the axon to open, etc, until the impulse reaches the end of the axon (axon TERMINAL or BOUTON), where different pores are caused to open which allow CALCIUM ions in, which cause small bags (VESICLES) containing neurotransmitter chemicals to move to and merge with the cell membrane, releasing the neurotransmitter chemicals into the synapse.

The synapse is a small GAP between a pre-synaptic neuron and a post-synaptic neuron.
The two parts of the synapse, the axon terminal and the dendrite (or in some cases a protrusion from a dendrite called a dendritic SPINE), are held together in position by small molecules sticking out from each neuron, called SYNAPTIC ADHESION MOLECULES.

Answer 4

• Nerve impulses received at the neuronal dendrites and are carried along the axon to the terminal branches. At the end of the branches there is a synapse. Chemical or electrical impulses cross the gap and go to the dendrites of surrounding cells.

Answer 5

The impulses can only travel from the axon of one neuron to the dendrite of another neuron.