obstruction to blood circulation, and
leads to a
(damage to part of the
brain due to interrupted blood supply).
Blockage may be due to
(clot formation) or to
fragment, or an air bubble carried in
the circulation). Rupture of vessels may
result in different patterns of bleeding:
the brain) or
(bleeding around the brain).
Any disease affecting an artery supply-
ing blood to areas inside the brain.
(narrowing of the arteries) and defects
in arterial walls that cause
balloon-like swelling in an artery).
The disease may eventually cause a
narrowing of blood vessels throughout
the brain can be a cause of
The largest and most developed part of
and the site of most con-
scious and intelligent activities.
The main components of the cerebrum
are two large hemispheres that grow
out from the upper part of the
(an extension of the spinal cord).
The surface of the cerebrum is made up
of a series of folds called gyri, w hich
are separated by fissures called sulci,
w ith a deep longitudinal fissure sepa-
rating the two hemispheres.
The four main surface regions of
each hemisphere - the frontal, pari-
etal, temporal, and occipital lobes - are
named after the bones that are over-
lying them. Each hemisphere has a
central cavity, called a
filled w ith
ty is surrounded by an inner layer,
consisting of clusters of nerve cells
There is a m id-
mainly of nerve fibres, w hich carry
information between particular areas
and between the cortex,
central brain, and
surface layer of each hemisphere is the
cerebral cortex, w hich is also known as
where much of the sen-
sory information from organs such as
the eyes and the ears is processed. A
thick band of fibres called the corpus
callosum carries nerve signals between
the two cerebral hemispheres.
Specific sensory processing takes place
in separate regions. For example, visual
perception is located in a part of the
occipital lobe called the visual cortex.
The cortex also contains “motor’’
areas concerned w ith initiating signals
for movements of the skeletal muscles.
Linked to the sensory and motor areas
from various senses and also perform
functions such as comprehension and
recognition, memory storage and re-
call, thought, and decision-making.
Some cortical functions are localized
to one “ dominant’’ hemisphere
many left-handed people). Two clearly
defined areas in the dominant hem i-
sphere are Wernicke’s area, w hich is
responsible for the comprehension of
Broca’s area, w hich is concerned with
Damage to particular areas of the cere-
brum may cause specific syndromes.
damage to the frontal
lobe may cause mental apathy, whereas
a parietal lobe injury may result in geo-
graphical disorientation. Disease of the
(memory loss), and visual defects may
result from occipital lobe damage.
Quite often, however, cerebral dis-
ease causes nonspecific symptoms such
as convulsions and headaches.
An outdated term for procedures to
commit a person to be compulsorily
detained for mental health treatment.
The medical term for
A brand-named preparation used for
the removal of