[Answer] 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?

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.

[Answer] 4. A is for what part of the neurone that carries impulses away from the cell body?

Step 1 : Introduction to the question "4. A is for what part of the neurone that carries impulses away from the cell body?"

...1. Axon 2. Aneurysm 3. Aqueduct 4. Arachnoid Axons are usually coated in a white fatty substance called the myelin sheath which helps to speed the passage of impulses. They are sometimes called axones. An aqueduct is a canal or passage. There are two in the brain: the Sylvian aqueduct and the Cerebral aqueduct. The arachnoid is the delicate middle layer of the meninges. Its fine web-like appearance gives rise to its name. An aneurysm is a sac formed by a dilation in a vessel wall, usually an artery.

[Answer] 7. Which D is for the threadlike extensions of neurone cytoplasm?

Step 1 : Introduction to the question "7. Which D is for the threadlike extensions of neurone cytoplasm?"

...1. Dendrites 2. Dendraxon 3. Diencephalon 4. Dura mater The dendrites form most of the receptive surface of the neurone. They carry information and impulses to the cell body. The diencephalon is the posterior part of the forebrain and consists of the hypothalamus, thalamus and epithalamus. A dendraxon is a neurone whose axon splits into terminal filaments immediately after leaving the cell. The dura mater is the toughest, outermost layer of the meninges.