How does a nerve impulse begin?

Answer 1

In order a nerve impulse to be generated there needs to be a stimulus. A stimulus would be you burning your finger or bumping your arm. Once the nerve impulse has been generated it sends off to the neurons in your brain so that your brain can tell you to move your hand.

Answer 2

Nerve impulses are transmitted between neurons, into neurons, and along neurons. They are transmitted between neurons at a synapse, into neurons at a dendrite, and along neurons at the axon.

Transmission at the synapse is via neurotransmitters released from the end of one neuron into the synapse, where they diffuse quickly over to the next neuron, usually to a dendrite or dendritic spine.

Transmission into the next neuron is by the neurotransmitters causing pores to open in the next neuron which allow Sodium ions to enter, which begin to propagate a electrochemical impulse by electrotonic conduction along a dendrite and across the soma. Electrotonic conduction is a process in which ions "bump" one another, causing them to somewhat "pile up" eventually at the axon hillock at the beginning of the axon. It's a very fast process, but it looses strength along the way, so in order for the axon to fire, there needs to be either many dendrites contributing, or one or more dendrites being stimulated quickly and often, so as to allow a summation of the voltages resulting from the "pile up" of the ions at the axon hillock.

Transmission along the axon of the neuron is by the action potential, which involves a successive exchange of Sodium and Potassium ions, each exchange causing the next.

for more about the action potential, see:

How_does_a_nerve_impulse_get_transmitted_along_an_axon

original answer:

Nerve Impulses are transmitted electrochemically via an action potential.

Information (either a sensation such as being touched, or a desire for action such as moving your hand and picking up a pen) is passed from the nerves dendrites to its axon which stimulates the action potential.

The action potential is a whole subject in itself.

Answer 3

INITIATED either by a physical stimulation of a SENSORY NEURON, or simply by ANOTHER NEURON at a SYNAPSE (the space between neurons). TRANSMITTED across a synapse (via the release of NEUROTRANSMITTERS), and then along DENDRITES (the receiving parts of the neuron) and the SOMA (the body of the neuron), in a process called ELECTROTONIC CONDUCTION, and then along the AXON (the output part of the neuron) in a process referred to as the ACTION POTENTIAL.

Answer 4

When a neuron is stimulated by another neuron or by the environment

Answer 5

Nerve impulses are initiated and transmitted according to nerve reactions and messages that get passed along or transmitted along nerve synapses and zones.