SEBORRHOEA
SELF-IMAGE
S
into hair follicles or discharge directly
on to the skin surface. They are most
numerous on the scalp, face, and anus
and are absent from the palms and soles
of the feet. Sebum production is partly
controlled by
androgen hormones.
Dis-
orders of the sebaceous glands may
lead to
seborrhoea
or
acne
vulgaris.
seborrhoea
Excessive
secretion
of
sebum,
causing oiliness of the face and
a greasy scalp. The cause is unclear, but
androgen hormones
play a part. Sebor-
rhoea is most common in adolescent
boys; those affected are more likely to
develop seborrhoeic
dermatitis
and
acne
vulgaris. The condition usually improves
in adulthood without treatment.
seborrhoeic dermatitis See
dermatitis.
sebum The oily secretion produced by
the
sebaceous glands
of the
skin.
Sebum
lubricates the skin, keeps it supple, and
protects it from becoming waterlogged
or dried out and cracked. It also protects
the skin from invasion by bacteria and
fungi. Oversecretion of sebum (see
seb-
orrhoea)
causes greasy skin and may
lead to seborrhoeic
dermatitis
or
acne.
secondary A term applied to a disease
or disorder that results from or follows
another disease (the
primary
disease).
It also refers to a malignant tumour that
has spread from a primary cancer else-
where in the body (see
metastasis
).
secretin A hormone produced by the
duodenum
when acidic food enters it
from the stomach. Secretin stimulates
the release of pancreatic juice, which
contains bicarbonate to neutralize the
acid, and bile from the liver.
secretion The manufacture and release
by a cell, gland, or organ of substances,
(such as
enzymes
) needed for metabolic
processes elsewhere in the body.
secretory otitis media An alternative
name for
glue ear
.
sectioning A commonly used term to
describe the implementation of a sec-
tion of the
Mental Health Act
.
security object A significant item, such
as a favourite soft toy, that provides
comfort and reassurance to a young
child. Attachment to such an item is nor-
mal and usually diminishes by age 7 or
8
.
sedation The use of a drug to calm a
person. Sedation is used to reduce
excessive
anxiety
and to control danger-
ously aggressive behaviour. It may also
be used as part of
premedication.
sedative drugs A group of drugs used
to produce
sedation.
Sedative drugs in-
clude
sleeping drugs, antianxiety drugs,
antipsychotic drugs,
and some
antide-
pressant drugs.
A sedative drug is often
included in a
premedication
.
seizure A sudden episode of abnormal
electrical activity in the
brain.
Recurrent
seizures occur in
epilepsy.
Seizures may be partial or generalized.
In a partial seizure, the abnormal activity
is confined to one area of the brain.
Symptoms include tingling or twitching
of a small area of the body,
hallucinations
,
fear, or
déjà vu.
In a generalized seizure,
the abnormal activity spreads through
the brain, causing loss of consciousness.
Causes of seizures include
head injury,
stroke
,
brain tumour
, infection, metab-
olic disturbances, withdrawal in
alcohol
dependence
, or hereditary alcohol intol-
erance. In children, high fever may cause
seizures.
Anticonvulsant drugs
can con-
trol seizures or reduce their frequency,
selective serotonin reuptake inhib-
itors (SSRIs) A relatively new class of
drugs that are used to treat
depression.
They work by blocking the reabsorption
of the neurotransmitter serotonin follow-
ing its release in the brain. The increased
serotonin levels that result are associa-
ted with improved mood. Common drugs
in this group include fluoxetine and
ser-
traline.
SSRIs are usually taken orally
once a day; it may take 1-3 weeks for any
noticeable improvement in symptoms.
SSRIs usually produce fewer side effects
than other types of antidepressant drug.
However, they may cause diarrhoea,
nausea, restlessness, and anxiety.
selenium A
trace element
that may help
to preserve the elasticity of body tis-
sues. The richest sources are meat, fish,
whole grains, and dairy products.
self-help organizations Organizations,
usually set up by patients or their rel-
atives, that provide people affected by
particular conditions with information,
support, and, sometimes, financial aid.
self-image A person's view of his or her
own personality and abilities. Some neu-
rotic disorders stem from an incongruity
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