How the Brain Works The Facts Visually Explained by DK (z-lib.org)

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THE PHYSICAL BRAIN

Brain Cells

Glia

The nervous system relies on a team of helper cells

called glia. Astrocytes control what chemicals enter

the brain from the blood. Oligodendrocytes produce

myelin for brain cells, forming the white matter.

Ependymal cells secrete the cerebrospinal fluid, while

microglia work as immune cells, clearing out waste

cells. Radial cells are the progenitors of neurons.

Helper cells

There are eight main

types of glia, but

only five are

common in the

brain. They protect

the overall health of

the nervous system.

Insulation

An axon may be covered in a

sheath of fat called myelin. This

works like insulation, preventing

electrical charges from leaking out

and thus speeding up the signal.

ASTROCYTES

DNA

OLIGODENDROCYTES

EPENDYMAL CELLS MICROGLIA RADIAL GLIA

CELL^ NU

CL

EU

S

N

ER

VE

CEL

L^ BODY

AXON

M

YE

LIN

Mitochondria

process glucose

Cell membrane

conveys nerve

impulses

Lysosomes destroy

waste chemicals

Golgi body

packages

chemicals

Chemicals crossing

from neighboring cell

create an electrical

pulse in dendrite

A single combined

electrical signal is sent

out to the next cell

Neurofibrils

AXON

MEMBRANE

M

YE

LIN

(^) SHE
ATH
Some neurons in
peripheral nervous
system have myelin-
producing Schwann cells
Myelin sheath is
coiled around axon
Blood vessel
supported Myelin sheath
produced here
Cilia help move
neurotransmitters
Damaged
neurons
detected here
Developing
neuron
Long,
straight cell
provides
support
Inside a neuron
A neuron contains broadly
the same set of organelles,
or internal structures, as any
other cell for releasing energy,
making proteins, and managing
genetic material.
US_020_021_Brain_Cells.indd 21 20/09/2019 12:31