Component |
Function(s) |
Structure |
Cerebellum |
Maintenance of muscle
tone, balance, and the synchronization
of activity in groups of muscles under
voluntary control, converting muscular
contractions into smooth coordinated
movement.
However, it does not initiate movement
and plays no part in the perception
of conscious sensations or in intelligence. |
The cerebellum is the largest
part of the hindbrain.
It bulges back behind the pons varolii and
the medulla oblongata, and is overhung by
the occipital lobes of the cerebrum. Like
the cerebrum, it has an outer grey cortex
and a core of white matter.
The cerebellum has three broad bands of
nerve fibres – the inferior, middle,
and superior cerebellar peduncles –
which connect it to the medulla, the pons
varolii, and the midbrain respectively. |
Cerebrospinal Fluid (CSF) |
Bathes the brain and spinal cord Allows nutrients and waste products to diffuse between the blood and the brain / spinal cord Protects the nerves against mechanical damage
Cerebrospinal fluid
is also the subject of
cranio-sacral therapy, which is a
huge subject in it's own right. |
A clear watery fluid whose normal contents
include glucose, salts, enzymes, and some
white blood cells (but no red blood cells).
This fluid moves within its cavity, typically
beating at 6-12 beats per minute, though
this can rise to 12-50 beats per minute
(such as in the case of a person who has
a "pulsating" headache). |
Cerebrum |
The Cerebrum is also known
as the Cortex
(Cortex = Cerebrum), and is the largest
and most highly developed part of the brain.
This is the ‘learning’ part
of the brain, and the seat of all intelligent
behaviour. It is responsible for the initiation and
coordination of all voluntary activity in
the body and for governing the functioning
of lower parts of the nervous system. |
The cerebrum is composed
of two hemispheres separated from
each other by the longitudinal fissure
in the midline.
Each hemisphere has an outer layer of grey matter, the cerebral cortex, below which lies white matter containing the basal ganglia. Nerves of the cortex are arranged on the outside surfaces as grey matter.
The corpus collosum is a massive bundle of nerve fibers that connect the two hemispheres - at the bottom of the longitudinal fissure.
|
|
| Hypothalamus |
The hypothalamus is
the "Receptor Centre", and
"Control Centre" of the
body.
It contains several
important centers controlling body
temperature and eating, and water
balance. Examples include osmo-receptors
that balance water/salt levels and
control the water content of the blood.
(See diagram opposite.)
It is also the Saiety
Center (that is concerned with 'satisfaction'),
for things like hunger, thirst, sex.
It is also closely
connected with emotional activity
and sleep, and it functions as a center
for the integration of hormonal and
autonomic nervous activity through
its control of the pituitary secretions.
The posterior lobe
of the pituitary secrets two hormones:
A.D.H. (Anti-diuretic hormone, as known as vasopressin – in U.S.)
This works on the kidney tubules. Secretion of ADH tells the kidneys to re-absorb more water, resulting in more concentrated urine. Non-secretion of ADH results in more peeing, and weaker urine. -
Oxytocin
|
The region of the forebrain in
the floor of the third ventricle,
linked with the thalamus above and
the pituitary gland below.
|
|
Medulla Oblongata |
The functions of the
medulla oblongata concern the body's
involuntary processes, such as:
Breathing Heart-rate Swallowing Salivation Vomiting Blinking
The cranial nerves VI – XII leave the brain in
this region. |
The medulla oblongata is the extension within the skull of the upper end of the spinal cord, forming the lowest part of the brainstem. |
|
The Meninges |
Mechanical protection of the brain and spinal column. |
The meninges consist of three parts, the dura mater, the arachnoid mater, and the pia mater.
The structures of these are mentioned below. |
Meninges -
Dura Mater |
|
The outer-most layer of the meninges
is inelastic, tough, and thicker than the
other two layers. |
Meninges -
Arachnoid Mater |
|
The inner two membranes are
together called the leptomeninges; between
them circulates the cerebrospinal fluid. |
Meninges -
Pia Mater |
|
Pons Varolii |
The pons varolii is the part of the brainstem that links the medulla oblongata with the thalamus. |
Contains numerous nerve tracts between the cerebral cortex and the spinal cord, and several nuclei of grey matter.
(The trigeminal nerves emerge from the front surface of the pons varolii.) |
