We can observe a phenotype whether or not we understand the genetics behind it. In real life, there is a gene called HERC2 that works like I described, and most people with blue eyes have the broken allele of this gene.
Nerves, Neuroglia, and Ganglia. A nerve is a bundle of fibres (axons and/or dendrites) outside the CNS. Neuroglia are cells of the nervous system that help protect and support it. Ganglia are groups of nerve cell bodies lying outside the CNS.
There are two sets of nerves: the central nervous system and the peripheral (outside) nervous system. The central nervous system is made up of the brain and spinal cord. The peripheral (outside) nervous system is all the other nerves in the body. The nerves are very close together.Special chemicals called neurotransmitters carry messages from one nerve to the next nerve.Drugs affect the body by changing the neurotransmitters in the nerves.he peripheral (outside) nervous system is all the other nerves in the body. The nerves are very close together. Special chemicals called neurotransmitters carry messages from one nerve to the next nerve. Drugs affect the body by changing the neurotransmitters in the nerves.