Page 190 - The Miracle of Electricity in the Body

188 THE MIRACLE OF ELECTRICITY IN THE BODY

Stem cells
Ventricles
Olfactory bulb

Stem cell
Stem cells’
Newly formed
precursor cell migratory
path
Hippocampus

Half the cells
die.

Astrocyte Neurons

Sparse
dendrites

Glial cells

The brain must be able to function from the moment of birth if a person is to enjoy a
normal life. Therefore, the number of neurons in the brain of a newborn is the same
as that in an adult, even if the connections between them have not yet been com-
pleted. During the development of the fetus, the brain produces around 360 million
new cells a day.

up excess toxic chemicals. When the neurons themselves are actively
damaged, astrocytes work twice as hard, doubling in size and number
to maintain the high levels of substances needed to repair the damage.
Each one of these important tasks is carried out by cells invisible to the
naked eye.