The adrenal glands (also known as suprarenal
glands) are endocrine glands that sit atop the
kidneys; in humans, the right suprarenal gland is
triangular shaped, while the left suprarenal gland is
It is pyramidal in structure and weights about four
These hormones control many important functions in the
body, such as:
1. Maintaining metabolic processes, such as managing
blood sugar levels and regulating inflammation
2. Regulating the balance of salt and water
3. Controlling the "fight or flight" response to stress
4. Maintaining pregnancy
5. Initiating and controlling sexual maturation during
childhood and puberty
Each adrenal gland has two distinct structures, the
adrenal cortex and the medulla, both of which
The cortex mainly produces cortisol, aldosterone and
androgens, while the medulla chiefly produces
epinephrine and norepinephrine.
Parts Of Adrenal Gland
The adrenal cortex is devoted to the synthesis of
Specific cortical cells produce particular hormones
including cortisol, corticosterone, androgens such as
testosterone, and aldosterone.
The cortex is regulated by neuroendocrine hormones
secreted by the pituitary gland and hypothalamus, as well
as by the renin-angiotensin system.
It is divided into 3 zones in the adult gland:
1. Zona Glomerulosa,
2. Zona Fasciculata,
3. Zona Rericularis.
Is divided onto 4 zones in the fetal gland.
The three zones of the permanent cortex constitutes
only 20% of the fetal gland’s size. The remaining
zone (fetal cortex) comprises up to 80% of gland’s
size during fetal life.
The outermost layer, the zona glomerulosa is the
main site for production of mineralocorticoids,
Aldosterone is largely responsible for the long-
term regulation of blood pressure.
Complete failure to secrete aldosterone leads to death
(dehydration, low blood volume).
Hyperalsdosterone states: Contribute to
hypertension associated with increased blood
Situated between the glomerulosa and reticularis,
the zona fasciculata is responsible for producing
glucocorticoids, chiefly cortisol in humans.
The zona fasciculata secretes a basal level of
cortisol but can also produce bursts of the
hormone in response to adrenocorticotropic
hormone (ACTH) from the anterior pituitary.
The inner most cortical layer, the
zona reticularis produces androgens, mainly
dehydroepiandrosterone (DHEA) and
DHEA sulfate (DHEA-S) in humans.
Use as immunosuppressant
Hyperimmune reactions (bee stings)
Serious side effects
Hypercortisolism (Cushing's syndrome)
Tumors (pituitary or adrenal)
Iatrogenic (physician caused)
Hypocortisolism (Addison's disease)
The adrenal medulla is the core of the adrenal
gland, and is surrounded by the adrenal cortex.
The chromaffin cells of the medulla, named for
their characteristic brown staining with
chromic acid salts, are the body's main source
of the circulating catecholamines adrenaline
(epinephrine) and noradrenaline
Derived from the amino acid tyrosine, these
water-soluble hormones are major hormones
underlying the fight-or-flight response.
adrenal medulla receives input from the
sympathetic nervous system through
preganglionic fibers originating in the
thoracic spinal cord
the adrenal medulla lacks distinct synapses and
releases its secretions directly into the blood.
Cortisol also promotes epinephrine synthesis in
the medulla. Produced in the cortex, cortisol
reaches the adrenal medulla and at high levels,
the hormone can promote the upregulation of
(PNMT), thereby increasing epinephrine
synthesis and secretion.
Although variations of the blood supply to the
adrenal glands (and indeed the kidneys
themselves) are common, there are usually
three arteries that supply each adrenal gland:
1. The superior suprarenal artery is provided by
the inferior phrenic artery
2. The middle suprarenal artery is provided by the
3. The inferior suprarenal artery is provided by
the renal artery
Venous drainage of the adrenal glands is
achieved via the suprarenal veins:
1. The right suprarenal vein drains into the
inferior vena cava
2. The left suprarenal vein drains into the left
renal vein or the left inferior phrenic vein.
Adrenal Gland Disorders
Adrenal gland disorders occur when the adrenal
glands don’t work properly.
Sometimes, the cause is a problem in another
gland that helps to regulate the adrenal gland.
In other cases, the adrenal gland itself may
have the problem.
The treatment for Cushing’s syndrome depends
on the cause. If the excess cortisol is caused by
medication, your health care provider can
change dosages or try a different medication to
correct the problem.
If the Cushing’s syndrome is caused by the
body making too much cortisol, treatments
may include oral medication, surgery,
radiation, or a combination of these
Congenital adrenal hyperplasia
Congenital adrenal hyperplasia can’t be cured,
but it can be treated and controlled. People
with congenital adrenal hyperplasia can take
medication to help replace the hormones their
bodies are not making.
Some people with congenital adrenal
hyperplasia only need these medications when
they are sick, but others may need to take them
Doctors can successfully treat most pituitary
tumors with microsurgery, radiation therapy,
surgery, drugs, or a combination of these
Surgery is currently the treatment of choice for
tumors that grow rapidly, especially if they
threaten or affect vision.The treatment plan for
other pituitary tumors differs according to the
type and size of the tumor.