The central nervous system,,,ext

Forebrain, Midbrain, Hindbrain and
Spinal Cord

Shaddae Palmer
Nastassaja Lewis

The Central Nervous System is essentially the
brain and the spinal cord. The CNS receives
sensory information from the nervous system
and controls the body’s responses.





The Brain
The Forebrain
The Midbrain
The Hindbrain

Spinal Cord

Major Division

Ventricle

Principal Structures

Forebrain

• Lateral

(Basal ganglia, limbic
system and cerebral
cortex
(Thalamus and
Hypothalamus)

• Third
Midbrain

Cerebral aqueduct

Tectum
Tegmentum

Hindbrain

• Fourth

• Cerebellum, Pons
and Medulla Oblangata

There are two major sub-divisions of the
forebrain,
 the diencephalon
 the telencephalon

The diencephalon contains the thalamus and
hypothalamus which is responsible for motor control,
relaying sensory information between brain regions
and controlling autonomic functions.
The telencephalon is also know as the cerebrum.
This is the largest part of the forebrain.

The cerebrum covered by a layer of tissue
(cerebral cortex) consists of the left and
right hemisphere. They are connected by a
bond of fibers known as the Corpus Callosum
(facilitates communication between the two
hemispheres).
Each hemisphere of the cerebrum is also
composed of four lobes (frontal, parietal,
occipital and temporal).

The frontal lobe- responsible for body
movement and executive functions.
 The Parietal lobe- specialized for touch and
perception also sensitive to pressure and
pain
 The temporal lobe- the prime site of hearing,
understanding language and storing
memories
 Occipital Lobe- Specialized for vision at the
back of the cerebral cortex


 Determining

personality and intelligence

Perceiving
 Thinking
 Producing and Understanding Language
 Interpretation of Sensory Impulses
 Motor Function
 Planning and Organization
 Touch and Senation


It is located between the forebrain and the
hindbrain and is responsible for regulating
sensory processes. It consists of the tectum
and tegmentum.
The tectum is the dorsal (roof) part of the
midbrain; includes the superior and inferior
colliculi.

 superior

colliculi (ka lik yew lee) Protrusions
on top of the midbrain; part of the visual
system
 inferior colliculi Protrusions on top of the
midbrain; part of the auditory system.
The midbrain is also involved in the control
of body movement. Dopamine producing
neurons can also be found in the midbrain.
Damage to this area can lead to Parkinson's
disease.

This surrounds the fourth ventricle and consists
of two major divisions; the metencephalon and
the myelencephalon.
The METENCEPHALON includes the pons and the
cerebellum.
 Cerebellum- also called the “little brain”, it has
two hemispheres covered by the cerebellar
cortex and has a set of deep cerebellar nuclei.
These nuclei receive projections from the
cerebellar cortex and then send projections out
of the cerebellum to other parts of the brain.

 Each

hemisphere of the cerebellum is
attached to the dorsal (back)structure of the
pons by bundles of axons which includes the
superior, middles and inferior (cerebellar
peduncles).
 Damage to the cerebellum impairs our
walking, standing and co-ordinated
movements. Examples include a musician
playing a guitar or a dancer doing balanced
movements.

 It

receives visual, auditory, vestibular
(control, balance) and somatosensory
information (conscious perception of things
that affect our body) . Also, information
about individual muscle movements being
directed towards the brain. It integrates all
this information and modifies the motor
outflow creating a co-ordinating and
smoothing effect on the movements.
 Damage to the cerebellum results in jerky,
poorly co-ordinated, exaggerated
movements. Extensive damage to cerebellar
makes it even impossible to stand.

> Pons(means bridge)- is a large bulge in the
brain stem and lies between the
mesencephalon and the medulla oblongata.
The pons contain in its core, a portion of the
reticular formation (region in the brain stem
that is involved in multiple tasks) which
includes nuclei that are important to sleep
and arousal. It also contains a large nucleus
that relays information from the cerebral
cortex to the cerebrum.

The MYLENCEPHALON only contains one major
structure which is the medulla
oblongata(oblong marrow). It is the most
caudal(near the tail) portion of the brain
stem and its lower border is the rostral end
(front end) of the spinal cord.
It contains part of the reticular formation that
control vital functions such as regulation of
the cardiovascualar system, respiration and
skeletal muscle tonus.

This is a long conical structure approximately as
thick as our little finger. It principal function is
to distribute motor fibers to the effective
organism of the body(glands and muscles and to
collect somatosensory information to be passed
on to the brain.
 The spinal cord also has a certain degree of
autonomy (independence) from the brain and is
protected by the vertebral column which is
composed of twenty four individual vertebrae of
the cervical(neck),thoracic(throat),lumber
regions(lower back) and the fused vertebrea that
make up the sacral and coccygeal portions of the
column(located in the pelvic area).


 The

spinal cord passes through a hole in each
of the vertebrea(spinal foramens). It is about
two-thirds long as the vertebral column and
the rest of the space is filled my a mass of
spinal roots composing the cauda equina
(horse’s tail).
 In early embryotic development the spinal
cord and the vertebral column are the same
length but as development begins the
vertebral column grows faster then the spinal
cord.

 The

brain consist of three major divisions the
midbrain he forebrain and the hind brain.
 Development begins from early in the
embryonic life

The central nervous system,,,ext

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