How do nerve impulses cross the gap between nerve cells?

Answer 1

When an electrical signal, or impulse, reaches the end of an axon it triggers chemicals called transmitters. The electrical signals then become chemical ones as the transmitters cross the synapse, the gap between an axon and a dendrite. When they reach the dendrite of another neuron they spark a new electrical signal that then travels the length of that nerve cell. And it does this over and over until it reaches its destination.

Answer 2

There are two ways in which an electrical impulse may be carried from one neuron to another. These junctions are called synapses.


In a chemical synapse, the electrical impulse arrives at the presynaptic membrane and this triggers the release of neurotransmitter molecules from vesicles out into the synaptic cleft (the space between the two neurons). An example of a very common neurotransmitter in the brain is glutamate. The neurotransmitter molecules bind to receptors on the postsynaptic membrane and can either directly open ion channels, or cause a chain of biochemical events that result in the opening of ion channels. In turn, the opening of ion channels in the postsynaptic membrane causes the voltage across the membrane to change and thus the electrical impulse proceeds down the postsynaptic neuron. Depending on the neurotransmitter and ion channels in the postsynaptic membrane, the first impulse could also inhibit the second neuron from propagating electrical impulses.


The chemical synapse is much more common than the electrical synapse, described below.


In an electrical synapse, the membranes of the two neurons are very close together and specific proteins form channels between them. This allows ions to move between the cells and the electrical impulse can thus move from one neuron to the next.

Answer 3

Electoral impulse