ADJUVANT
ADRENAL GLAND DISORDERS
and abdomen; in women, it occurs on
the breasts, hips, and thighs.
adjuvant
A substance that enhances
the action of another substance in the
body. The term is usually used to des-
cribe an ingredient added to a
vaccine
to increase the production of antibodies
by the immune system, thus enhancing
the vaccine's effect. Adjuvant chemother-
apy is the use of
anticancer drugs
in
addition to surgical removal of a tumour.
Adlerian theory
The psychoanalytical
ideas set forth by the Austrian psychia-
trist Alfred Adler. Also called individual
psychology, Adler's theories were based
on the idea that everyone is born with
feelings of inferiority. Life is seen as a
constant struggle to overcome these
feelings; failure to do so leads to neuro-
sis. (See also
psychoanalytic theory.)
adolescence
The period between child-
hood and adulthood, which broadly
corresponds to the teenage years. Ado-
lescence commences and overlaps with,
but is not the same as,
puberty
.
ADP
The abbreviation for adenosine di-
phosphate, the chemical that takes up
energy released during biochemical reac-
tions to form
ATP
(adenosine triphos-
phate), the body's main energy-carrying
chemical. When ATP releases its energy,
ADP is reformed. (See also
metabolism.)
adrenal failure
Insufficient production
of hormones by the adrenal cortex (the
outer part of the
adrenal glands
). It can
be acute or chronic. Adrenal failure may
be caused by a disorder of the adrenal
glands, in which case it is called
Addi-
son's disease,
or by reduced stimulation
of the adrenal cortex by
ACTH,
a hor-
mone produced by the
pituitary gland.
adrenal glands
A pair of small, trian-
gular
endocrine glands
located above
the kidneys. Each adrenal gland has
2 distinct parts: the outer cortex and the
smaller, inner medulla.
The cortex secretes
aldosterone
, which,
together with hydrocortisone and cor-
ticosterone
and
small
amounts
of
androgen horm ones
helps to maintain
blood pressure. Hydrocortisone controls
the body's use of fats, proteins, and car-
bohydrates and is also important in
helping the body to cope with stress.
Hydrocortisone and corticosterone also
suppress inflammatory reactions and
some activities of the
immune system.
Production
of adrenal
cortical
hor-
mones is controlled by
ACTH
, which is
produced in the pituitary gland.
The adrenal medulla is part of the
sympathetic
autonomic nervous system.
In response to stress, it secretes the
hormones
adrenaline
(epinephrine) and
noradrenaline
(norepinephrine), which
increase heart-rate and blood flow.
ADRENAL GLANDS
STRUCTURE OF ADRENAL GLAND
adrenal gland disorders
A range of
uncommon but sometimes serious dis-
orders due to deficient or excessive
production of hormones by one or both
of the
adrenal glands
.
A genetic defect causes congenital
adrenal hyperplasia
, in which the ad-
renal cortex is unable to make sufficient
hydrocortisone and
aldosterone,
and
androgens
are produced in excess. In
adrenal failure,
there is also deficient
production of hormones by the adrenal
cortex; if due to disease of the adrenal
glands, it is called
Addison's disease
.
Adrenal tumours
are rare and generally
lead to excess hormone production.
In many cases, disturbed activity of
the adrenal glands is caused, not by
disease of the glands themselves, but
by an increase or decrease in the blood
level of hormones that influence the
action of the adrenal glands. For exam-
ple, hydrocortisone production by the
adrenal cortex is controlled by
ACTH
,
which is secreted by the pituitary gland.
Pituitary disorders can disrupt produc-
tion of hydrocortisone.
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