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

14

THE PHYSICAL BRAIN

Human and Animal Brains 1515

All mammal brains contain the same

components, but they grow in different

proportions. A third of the volume of a rat’s

central nervous system (CNS) is made up of

the spinal cord, indicating its reliance on

reflex movements. By contrast, the spinal

cord is a tenth of a human CNS. Instead,

three-quarters is taken up by the cerebrum,

which is used for perception and cognition.

VARYING PROPORTIONS

RAT BRAIN HUMAN BRAIN

EU

RO

PE

AN

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A
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DO
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Dolphin
The hearing and vision centers of a dolphin’s
brain are larger and closer together than in a
human brain. It is thought that this helps the
dolphin create a mental image using its sonar.
Shark
The brain of a shark is Y-shaped due to the
large olfactory bulbs that extend out on
either side. The sense of smell is the shark’s
primary means of tracking prey.
Cerebrum
Cerebrum
Olfactory bulbs
sit behind
nares, which
are nostril-like
openings that
smell water
DO ALL ANIMALS
HAVE A BRAIN?
Sponges have no nerve
cells at all, while jellyfish
and corals have a netlike
nervous system but no
central control point.
0 0.03 oz (0.9g) 1 g 0 1.05 oz (30g) 50 g 0 47.6 oz (1,350g)

0 2 0 0.9% 2 0 2% 2

1,400 g

0.9%

Cerebral cortex

is more folded

than that of

humans

0.04 oz 1.76 oz 49.4 oz

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