A neuron has three basic parts: the body or soma, the axon and the dendrites. The Cell body is the center for sending and receiving impulses. The axon is a tube like extension of a neuron. Axons extended can be up to 3 feet long (psychology textbook). Nerves are actually bundles of axons. Axon receives the impulse from the cell body and passes it on to the next neuron/muscle by neurotransmitters crossing the gap (synapse) between them. The myelin sheath is a fatty layer that surrounds the axon this helps speed up transmission of impulses. Movement is always in one direction - dendrite to cell body to axon. The Dendrites resemble limbs on a tree. They receive the impulses from the axon of neurons.
Neurotransmitters or the chemicals are released from a neuron. Neurotransmitters cross the synapse where they may connect to the neuron called a receptor that is activated. Neurotransmitters are either antagonist or agonist. Antagonist is a chemical that blocks a cells response to an action. While the agonist is a chemical that mimics (taken from the textbook) the effects of the original neurotransmitter.
All these actions take place between the brain and the nerves and happen faster than the speed of lightning. At the end of the action your arm will go up, your hand will open and you can now catch the ball. This is how I understood the