about how many nerve cells are in the brain?
The autonomic nerve cell bodies lie along a chain that runs parallel with the spinal cord and inside the vertebrae, while their axons exit in the spinal nerve sheaths. The brain, spinal cord and nerves consist of more than 100 billion nerve cells, called neurons. The Spinal Cord and Neurons. The spinal cord extends through hollow openings in each vertebra in your back. It contains various nerve cell bodies (gray matter) and nerve processes or axons (white matter) that run to and from the brain and outward to the body. The peripheral nerves enter and exit through openings in each vertebra. The number of neurons in the brain varies dramatically from species to species. One estimate (published in 1988) puts the human brain at about 100 billion (10 11) neurons and 100 trillion (10 14) synapses. The right side of your brain controls movements on the left side of your body whether you're right or left handed. The left side of your brain controls movements on the right side. That's why damage on one side of your brain affects the other side of your body. So if you have a stroke in the left part of your brain, your right arm or leg could be paralyzed. The average human brain has about 100 billion neurons (or nerve cells) and many more neuroglia (or glial cells) which serve to support and protect the neurons (although see the end of this page for more information on glial cells). A typical neuron consists of a cell body (soma), dendrites, and an axon. The term neurite is used to describe either a dendrite or an axon, particularly in its undifferentiated stage. These signals between neurons occur via synapses, specialized connections with other cells. Neurons can connect to each other to form neural networks. Neurons are the core components of the brain and spinal cord of the central nervous system (CNS), and of the ganglia of the peripheral nervous system (PNS). 1 Myelin is made of fat, and it helps to speed transmission of a nerve impulse down a long axon. 2  Myelinated neurons are typically found in the peripheral nerves (sensory and motor neurons), while nonmyelinated neurons are found within the brain and spinal cord. At the majority of synapses, signals are sent from the axon of one neuron to a dendrite of another. There are, however, many exceptions to these rules: neurons that lack dendrites, neurons that have no axon, synapses that connect an axon to another axon or a dendrite to another dendrite, etc. Neurons & Synapses. NEURONS & SYNAPSES The core component of the nervous system in general, and the brain in particular, is the neuron or nerve cell, the brain cells of popular language. A neuron is an electrically excitable cell that processes and transmits information by electro-chemical signalling.
100 billion