In another, speedier set of conditions, try imagining how an insect would fly if it could not see where it was going, or could not determine orientation with respect to its horizon. Within a flying insect, again, try imagining losing control of the small, direct flight muscles that control pronation of wings, or loss of coordination of the major flight muscles. It would be difficult to regard any area of insect biology that does not depend importantly upon nervous systems. Understanding insect nervous systems also has a certain practical significance because most insecticides work by poisoning one or another area of nerve function. The nervous system is made of neurons.
Every tissue is composed of cells.
Fat bodies are mostly made of trophocyctes. Muscles are composed of muscle cells. Similarly, nervous systems are composed of nerve cells, which are also called neurons. The first figure shows the general structures of nerve cells. Most major organelles, including cell nuclei, endoplasmic reticula, Golgi bodies, mitochondria and so forth are found in perikarya.