Neuron has three basic parts: the dendrites, the cell body, and the axons. some neurons have a fatty layer covering called around their axons. this layer isn’t continuous, and the gaps are called . the action potential jumps through these gaps to the transmission.

A neuron comprises three fundamental components, that is, the cell body, dendrites, and axons. Some of the neurons exhibit a fatty layer covering known as the Schwann cells enveloping their axons. This layer is not continuous, and the gaps are known as the nodes of Ranvier. The jumping of the action potential takes place via these gaps to elevate the speed of the transmission.  

The Schwann cells are the glial cells, which mainly offer myelin isolation from the axons of the vertebrate PNS. It prevails only at the PNS, while oligodendrocytes perform this function in the CNS, they form the myelin sheath surrounding a single axon.  

The gap between the two Schwann cells is known as the Ranvier's nodes. These nodes are the essential locations of ion exchange between the extracellular fluids and the axon. This alignment permits saltatory conduction of the high-speed action potential that provides speed at certain occasions of more than one hundred meters in a second, and at the same time saves energy as well.  

weathering is the answer.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."