I
separating them into groups; it also
holds in place soft organs such as the
kidneys. Thick fascia in the palm of
the hand and sole of the foot have a
cushioning, protective function.
fasciculation
Spontaneous,
irregular,
and
usually
continual contractions of a muscle that
is apparently at rest. Unlike the con-
tractions of
fibrillation
,
fasciculation is
visible through the skin.
M inor
fasciculation,
such
as
that
occurring in the eyelids, is common
and is no cause for concern. However,
persistent fasciculation w ith weakness
in the affected muscle indicates dam-
age to the nerve cells in the spine that
control the muscle, or to the nerve
fibres that connect the spinal nerves to
the muscle;
motor neuron disease
is one
such disorder.
fasciitis
Inflammation
of
a
layer
of
fascia
(fibrous
connective
tissue),
causing
pain and tenderness. Fasciitis is usually
the result of straining or injuring the
fascia surrounding a muscle; it most
commonly affects the sole of the foot.
The condition may occur in people
who suffer from
ankylosing spondylitis
(a rheumatic
disorder
affecting
the
spine) or those with
Reiter’s syndrome
(inflammation of the urethra, conjunc-
tivitis, and arthritis).
Treatment of fasciitis involves resting
the affected area and protecting it from
pressure. A local injection of a
cortico-
steroid drug
may be given. If fasciitis is
part of a widespread disorder of the
joints, treatment of this condition w ill
generally improve symptoms. (See also
necrotizing fasciitis
. )
fascioliasis
A disease affecting the liver and bile
ducts that is caused by infestation with
the
liver fluke
species F
a s c i o i a
h e p a t i c a .
Fascioliasis is acquired through eating
plant food (such as watercress) conta-
minated w ith the larvae of the fluke.
Treatment is w ith
anthelmintic drugs
.
fasciotomy
An operation to relieve pressure on
muscles by making an incision in the
fascia
(fibrous connective tissue) that
surrounds them.
Fasciotomy is usually performed to
treat
compartment syndrome
,
a painful
condition in w hich constriction of a
group of muscles causes obstruction of
blood flow; it gives the muscles space
in w hich to expand. The procedure is
also sometimes performed as a surgical
emergency after an injury has resulted
in muscle swelling or bleeding w ithin
a muscle compartment.
fasting
Abstaining from all food and drinking
only water. In temperate conditions
and
at moderate
levels
of physical
activity, a person can survive on water
alone for more than two months; how -
ever, without consuming either food
or drink, death usually occurs w ithin
about ten days.
EFFECTS ON THE BODY
In the absence of food, the energy that
is needed in order to maintain essential
body processes is
supplied by
sub-
stances stored in the body tissues. About
six hours after the last meal, the body
starts to use
glycogen
(a carbohydrate
stored in the liver and muscles). This
process continues for about 24 hours,
after w hich time the body obtains en-
ergy from stored fat and by breaking
down protein in the muscles. If fasting
continues, the body’s
metabolism
slows
down in an attempt to conserve energy,
and the fat and protein stores are con-
sumed more slowly.
In the initial stages of fasting, weight
loss is rapid. It then slows down, not
only
due
to
the
slowing
of
the
metabolism, but also because the body
begins
to
conserve
its
salt
supply,
resulting in the retention of water in
the
tissues.
This
accumulated
fluid
causes
oedema
(swelling), w hich p rin-
cipally affects the legs and abdomen.
In prolonged fasting, the ability to
digest food may be impaired because
the stomach stops secreting digestive
juices. Prolonged fasting also halts the
production of sex hormones, causing
amenorrhoea
(the absence of menstru-
ation) in women.
fat
A substance that is composed of one or
more
fattyacids
. Fat is the main form in
w hich energy is stored by the body. A
layer of fat, known as
adipose tissue
,
lies directly beneath the skin and sur-
rounds various internal organs. Excess
amounts of fat are deposited under the
skin in
obesity
.
(See also
fats and oils
. )
fatal
Causing, or ending in,
death
.
FATS AND OILS
fat atrophy
Localized loss of fatty tissue beneath
the skin. Fat atrophy can occur at injec-
tion
sites
in
people
w ith
type
1
(insulin-dependent)
diabetes mellitus.
A
particular pattern of fat atrophy also
develops in some people being treated
w ith
antiretroviral drugs
for
HIV
infection
or
AIDS
(see
lipodystrophy
) .
fatigue
See
tiredness
.
fat pad
F
A localized collection of fatty tissue. Fat
pads are norm ally found in parts of the
body that need cushioning and protec-
tion,
such
as
behind
the
eyeballs,
around the kidneys, behind the knees,
under the heel bone, and in the cheeks
(especially in infants). Abnormal fat
pads may be noncancerous tumours
(see
lipoma
) or may develop in certain
disorders, such as
lipodystrophy
.
fats and oils
Nutrients that provide the body with
its most concentrated form of
energy
.
Fats are the largest group of
lipids
,
and
are compounds containing chains of
carbon and hydrogen atoms with very
little oxygen. Chemically, they consist
mostly of
fatty acids
combined with
glycerol.
Fats are usually solid at room
temperature, w hile oils are liquid.
TYPES
Fats and oils are divided into two main
groups - saturated and unsaturated -
depending
on
the
proportion
of
hydrogen atoms they contain. If the
fatty acids contain the maximum possi-
ble quantity of hydrogen, the fats are
saturated. If some sites on the carbon
chain are
unoccupied by hydrogen,
they are unsaturated. Monounsaturated
fats are unsaturated fats w ith only one
site that could take an extra hydrogen
atom; if many sites are vacant, the fats
are polyunsaturated. Animal fats, such
as those in meat and dairy products,
are largely saturated; vegetable fats tend
to be unsaturated.
FAT AND HEALTH
The amount and types of fat in the diet
have important implications for health.
A diet containing a large amount of fat,
particularly saturated fat, is linked to
obesity and an increased risk of
athero-
sclerosis
(deposition of fat on the walls
of arteries) and of subsequent
coronary
artery disease
and
stroke
.
Other serious
disorders related to the consumption
299
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