The neuron is the basic building block of the nervous system, consisting of a cell body, dendrites, an axon, and terminal buttons. Neurons communicate via electrical and chemical signals. The brain develops rapidly after birth through processes like neuron and synapse growth and synaptic pruning, which refines connections. Early childhood is critical for brain development as experience shapes pruning and the formation of over 15,000 new connections per neuron. The brain remains plastic and can form new connections if damaged.

1. How Does the Brain Develop?

2. Everything we do, feel and say
from infancy to the end of life
reflect the functioning of our
brain
How is the brain organized?

3. The Neuron
The neuron is the basic building
block of the nervous system
‐ They are often grouped in bundles
called nerves.
There are billions and billions of
neurons throughout the body

6. 4 parts of the neuron
1. Dendrites are specialized to receive
signals from neighboring neurons and
carry them back to the cell body
Thin, bushy-like structures that receive
information from outside the neuron
Relays the information into the cell
body

7. The Neuron
2. The Cell body
contains the
cell nucleus
The cell body
relays the
information
down to the
axon

8. The structure of a neuron
3. Axon: A thin, long structure that
transmits signals from the cell body to
the terminal buttons.
‐ The axon is wrapped in myelin, a fatty
sheath that allows it to transmit information
more rapidly.

9. Once the information hits the
Terminal button, it is transmitted
outside the cell by
neurotransmitters, which reside
in the axon terminal.

11. The Neuron

12. Fun Facts
Average number of neurons in the human
brain
‐ 100 billion
Average number of neurons in an octopus
brain
‐ 300 million
Rate of neuron growth during
development of a fetus (while in the
womb)
‐ 250,000 neurons per minute

13. The information shoots from
one end of the neuron to the
other.
How do neurons
communicate?

14. Electrical Communication
Action potential is an electrical current
sent down the axon initiates the release
of neurotransmitter.
The activity within the neurons is
electrical. This current causes the neuron
to “fire”
When an action potential moves down the
axon, it causes the release of
neurotransmitters

15. Synaptic transmission
The neurons don’t actually touch each
other, there is a gap between one
neuron and the next called Synapses.
‐ The space between neurons
Information must be transmitted across
the synapse to other neurons via the
neurotransmitters.

16. Presynaptic Neuron
Postsynaptic Neuron

17. Neurotransmitters
Neurotransmitters are chemical
substances that reside in the axon
terminals
They communicate to other neurons by
binding to receptors on neighboring
neurons

18. What observations can you make
about the brain?

19. Brain
Development
The wrinkled outer
area of the brain is
called the Cerebral
Cortex-
The cortex
regulates many of
our functions that
we think of distinctly
human.
Your personality,
ability to carry out
plans, certain types
of thinking, memory,
sensory activity.

20. Looking at the Brain
The exterior covering (cortex) of the brain
is wrinkled which increases the surface
area of the brain
The brain is divided into 2 hemispheres
‐ Right and left hemispheres

21. The Corpus Callosum connects
these hemispheres and allows
communication from one side of
the brain to the other.

22. Corpus Callosum

23. The beginning of the brain can
be traced to the period of the
zygote
Approximately 3 weeks after conception a
groups of cells form a flat structure called
the neural plate

24. The neural plate folds to form a
tube that ultimately becomes the
brain and spinal cord
3 week old
zygote

25. Early Brain Development
In the months after birth the brain grows rapidly,
producing billions of neurons, dendrites and
axons, as well as synapses reaching its peak
around the infant’s first birthday.
-In the first 2 years the brain increases in size from 25%
to 75% of its adult weight
Soon after synapses soon to gradually disappear
a phenomenon known as synaptic pruning.
-This process is the brain’s way of “weeding out” the
unnecessary connections between neurons.

26. Brain growth and development
There is a fivefold increase in the number of
dendrites in cortex from birth to age 2 years,
as a result approximately 15,000 new
connections may be established per neuron.
‐ This is called “Transient exuberance”
These connections are necessary because
thinking and learning require many
connections between many parts of the brain
Experience is vital for brain formation

27. If cells are unused they atrophy
and are rededicated to other
senses. Underused neurons, like
synapses are inactivated by
pruning process

28. When children suffer brain damage,
cognitive processes are usually
impaired; these processes often
improve gradually showing the
brain’s plasticity
The brain’s organization is somewhat flexible
and if damaged the brain can make new
connections