Step 1 : Introduction to the question "5. In between neurones there is a small gap along which chemicals are sent from one neurone to the other. What is the name given to these chemical substances?"
...1. Nephrotransmitters 2. Cardiotransmitters 3. Hepatotransmitters 4. Neurotransmitters These neurotransmitters are essential if the impulse from one neurone is to be propagated along the axon of the next neurone. The neurotransmitters are secreted from the first neurone, stimulated to do so by the presence of calcium ions (Ca2+), and subsequently bind to protein receptors on the second neurone. This results in the diffusion of sodium ions (Na+) and potassium ions (K+) in and out of the second neurone, thus generating an impulse. Examples of neurotransmitters are noradrenalin and acetylcholine.