Question

which chemical is present in nerves cell?
why we call like the message in our body is travelled like electrical impulses is that in the form of electricity

Answer 1

• Neurons communicate with one another at junctions called synapses. At a synapse, one neuron sends a message to a target neuron—another cell.
• Most synapses are chemical; these synapses communicate using chemical messengers. Other synapses are electrical; in these synapses, ions flow directly between cells.
• At a chemical synapse, an action potential triggers the presynaptic neuron to release neurotransmitters. These molecules bind to receptors on the postsynaptic cell and make it more or less likely to fire an action potential.

Electrical synapses
At electrical synapses, unlike chemical synapses, there is a direct physical connection between the presynaptic neuron and the postsynaptic neuron. This connection takes the form of a channel called a gap junction, which allows current—ions—to flow directly from one cell into another.

Electrical synapse showing presynaptic cell, gap junction, post-synaptic cell, and movement of positive ions from pre-synaptic cell to post-synaptic cell.
Image credit: based on similar image in Pereda^22start superscript, 2, end superscript, Figure 1
Electrical synapses transmit signals more rapidly than chemical synapses do. Some synapses are both electrical and chemical. At these synapses, the electrical response occurs earlier than the chemical response.
What are the benefits of electrical synapses? For one thing, they're fast—which could be important, say, in a circuit that helps an organism escape from a predator. Also, electrical synapses allow for the synchronized activity of groups of cells. In many cases, they can carry current in both directions so that depolarization of a postsynaptic neuron will lead to depolarization of a presynaptic neuron. This kind of bends the definitions of presynaptic and postsynaptic!
What are the downsides of electrical synapses? Unlike chemical synapses, electrical synapses cannot turn an excitatory signal in one neuron into an inhibitory signal in another. More broadly, they lack the versatility, flexibility, and capacity for signal modulation that we see in chemical synapses.