Basic structure of the Nervous System 2 part two

First part is here https://steemit.com/body/@skytoin/basic-structure-of-the-nervous-system
All the Nervous system is the densely packed with cells and only 20% of it is consist of extracellular space. These cells include neurons or nerve cells. Neurons respond to stimuli and transfer signals. Neurons are surrounded, protected by glial cells (gaggles of neuroglia) . There are many types of glial cells and they have many different functions. Fifty percent of the Brain mass is glial cells. Star shaped astrocytes are the most abundant glial cells in the central nervous system. Star shaped glial cells connect Neurons to the blood supply and control the exchange of the materials between neurons. There are microglial cells in the Central Nervous system, their role is to protect nervous system from invading microorganisms. Oligodendrocytes wrap neurons making the insulating barrier (the myelin sheath). The Peripheral nervous system has two kinds of glial cells. Satellite cells surround neuron cell bodies. Schwann glial cells wrap neurons making the insulating barrier (the myelin sheath).
Neurons are one of the longest cells in a body, neurons are one of the longest-lived cells in the body, they might live as long as you do. Also Neurons are the most energy consuming cells. They have big appetite for calories. They need constant big supply of glucose and oxygen plus the 25% of all calories you eat. The structure of neurons includes cell body (soma). Soma has nucleus, DNA, mitochondria, ribosomes and cytoplasm. The branchy things that grow out of Soma are Dendrites. They deliver signals from other Neurons to Soma (cell body). The big tail out of Soma is the Axon. It sends out signals to other Neurons.