Facts & figures: The central nervous system

Our central nervous system is a marvel of nature and an essential control system of our body. While many of its processes are still not decoded, scientists can reveal these impressive statistics:

0.0000001

Weight in grams of a large neuron (nerve cell)

0.00001

Diameter in meters of a neuron

35

Average weight in grams of the human spinal cord

45

Average length in centimetres of the human spinal cord

1,300

Average weight in grams of a human brain

1,000 to 10,000

The number of synapses for each neuron in the human brain

Synapses are the functional connecting structure between a nerve cell axon and target cells (e.g. other nerve cells, muscle cells or gland cells).

1,000,000,000

There are about one billion neurons in the spinal cord

100,000,000,000

There are about one hundred billion neurons in the human brain

1,000,000,000,000

There are about one trillion glial cells in the human brain

Glial cells are supporting cells of the central nervous system. The do not only provide physical support, but they also respond to injury, regulate the chemical composition surrounding cells, form the myelin insulation of nervous pathways, and help guide neuronal migration during development.

1,000,000,000,000,000

There are about one quadrillion synapses in the human brain