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The suprarenal glands (adrenal glands) are paired endocrine organs lying on the superior poles of the kidneys.
They are retroperitoneal and surrounded by perinephric fat within the renal fascia, separated from the kidneys by a thin fibrous septum.
Each gland weighs about 4–5 g and is golden-yellow in color due to lipid content.
Shape: Triangular or pyramidal.
Position: Lies on the upper pole of right kidney, behind the inferior vena cava.
Relations:
Anterior: Right lobe of liver, inferior vena cava.
Posterior: Diaphragm.
Medial: Inferior vena cava.
Hilum: On anterior surface where veins emerge.
Shape: Crescentic or semilunar.
Position: Lies on the upper medial border of the left kidney.
Relations:
Anterior: Stomach (through omental bursa), pancreas, spleen.
Posterior: Diaphragm.
Medial: Aorta.
True capsule: Condensation of connective tissue of gland.
False capsule: Formed by renal fascia enclosing perinephric fat.
Each gland has two parts:
Cortex (outer yellow layer)
Derived from mesoderm.
Secretes steroid hormones.
Divided into three zones:
Zona glomerulosa: Mineralocorticoids (aldosterone).
Zona fasciculata: Glucocorticoids (cortisol).
Zona reticularis: Sex steroids (androgens).
Medulla (inner dark brown core)
Derived from neural crest cells.
Contains chromaffin cells (modified post-ganglionic sympathetic neurons).
Secretes catecholamines — adrenaline and noradrenaline.
Under sympathetic control, not pituitary.
| Part | Hormones | Main Function |
|---|---|---|
| Cortex | Aldosterone | Sodium and water retention, ↑ BP |
| Cortex | Cortisol | Glucose metabolism, stress response, anti-inflammatory |
| Cortex | Androgens | Secondary sexual characters |
| Medulla | Adrenaline/Noradrenaline | “Fight-or-flight” response — ↑ heart rate, BP, blood glucose |
Each gland receives three main arteries:
Superior suprarenal arteries → from inferior phrenic artery
Middle suprarenal artery → from abdominal aorta
Inferior suprarenal artery → from renal artery
These form a subcapsular arterial plexus, which supplies both cortex and medulla.
Single suprarenal vein from each gland:
Right suprarenal vein → directly into inferior vena cava
Left suprarenal vein → drains into left renal vein
Venous blood from cortex flows through medulla before exiting, bathing medullary cells with cortical hormones (important for adrenaline synthesis).
To lateral aortic (para-aortic) and renal lymph nodes.
Preganglionic sympathetic fibers (T10–L1) via splanchnic nerves.
The medullary chromaffin cells act as modified sympathetic ganglion cells.
Cortex has no direct nerve supply, controlled hormonally by pituitary ACTH.
Cortex: Mesodermal coelomic epithelium.
Medulla: Neural crest (ectodermal).
Thus, the gland is a composite organ of dual origin.
Includes suprarenal medulla, paraganglia, and sympathetic ganglia that contain chromaffin cells.
Chromaffin reaction: Cells stain brown with chromic salts (due to oxidation of catecholamines).
Extra-adrenal chromaffin bodies: Organ of Zuckerkandl (near aortic bifurcation), carotid body, sympathetic chain.
Addison’s disease: Hypofunction of cortex → low BP, pigmentation, weakness.
Cushing’s syndrome: Excess cortisol → moon face, obesity, hypertension.
Conn’s syndrome: Aldosterone excess → hypertension, hypokalemia.
Pheochromocytoma: Tumor of medulla → episodic hypertension, sweating, palpitations.
Adrenal hemorrhage (Waterhouse-Friderichsen): Seen in meningococcal septicemia → shock.
Congenital adrenal hyperplasia: Genetic enzyme defect → androgen excess, ambiguous genitalia.
Each gland has a single large central vein, which drains blood from both cortex and medulla.
Right suprarenal vein → short, opens directly into inferior vena cava.
Left suprarenal vein → long, joins left renal vein.
The medullary veins receive blood from the cortical sinusoids, so medullary cells are exposed to high steroid concentrations — aiding conversion of noradrenaline to adrenaline.
Lymphatics from both glands drain into lateral aortic (para-aortic) and renal lymph nodes.
No lymphatics from medulla directly reach cisterna chyli.
Supplied by preganglionic sympathetic fibers from T10–L1 spinal segments.
Cortex: Has no direct nerve supply; regulated hormonally by pituitary ACTH.
Medulla: Supplied by greater and lesser splanchnic nerves; chromaffin cells act as modified sympathetic neurons, secreting adrenaline and noradrenaline directly into blood.
Addison’s Disease:
Hypofunction of cortex → ↓cortisol & aldosterone.
Symptoms: Weakness, hypotension, pigmentation, salt loss.
Cushing’s Syndrome:
Hypersecretion of cortisol (often due to pituitary adenoma).
Features: Moon face, truncal obesity, hypertension, striae.
Conn’s Syndrome:
Hypersecretion of aldosterone.
Features: Hypertension, hypokalemia, muscle weakness.
Pheochromocytoma:
Tumor of medulla (chromaffin cells).
Causes episodic hypertension, palpitations, sweating, headache.
Waterhouse–Friderichsen Syndrome:
Bilateral adrenal hemorrhage in meningococcal septicemia.
Leads to acute adrenal insufficiency and shock.
Congenital Adrenal Hyperplasia:
Genetic enzyme deficiency (21-hydroxylase).
Excess androgens → ambiguous genitalia in females.
Adrenal Crisis:
Acute insufficiency due to sudden withdrawal of steroids or infection.
Cortex:
Zona glomerulosa: Arched clusters of small columnar cells secreting aldosterone.
Zona fasciculata: Long cords of lipid-laden cells (spongiocytes) secreting cortisol.
Zona reticularis: Network of darkly stained cells secreting sex steroids.
Medulla:
Chromaffin cells arranged in cords around veins.
Contain secretory granules rich in catecholamines.
Stain brown with chromic salts (chromaffin reaction).
Surrounded by sympathetic ganglion cells and venous sinusoids.
Cortex: From mesoderm of posterior abdominal wall.
Fetal cortex forms early, later replaced by definitive cortex.
Medulla: From neural crest cells, migrating inward to form chromaffin tissue.
By birth:
Gland relatively large due to prominent fetal cortex.
After birth, gland shrinks as fetal cortex regresses.
Steroidogenic Factor-1 (SF-1): Controls adrenal cortex development and steroidogenesis.
DAX-1 and WT-1 genes: Regulate cortical differentiation.
BMP and ACTH: Promote cortex proliferation.
Phox2B and Mash1: Control chromaffin cell differentiation in medulla.
The gland lies in perinephric fat at upper pole of kidney.
Carefully dissect the renal fascia to expose it.
Note that the right gland is smaller and pyramidal, left gland larger and semilunar.
Trace its veins to IVC (right) and left renal vein (left).
Identify three arteries entering at multiple points on the surface.
Comprises chromaffin cells found in adrenal medulla and in extra-adrenal sites (paraganglia).
These cells secrete catecholamines (adrenaline, noradrenaline) under sympathetic stimulation.
Chromaffin reaction: Cells stain brown due to oxidation of catecholamines with chromic salts.
Extra-adrenal chromaffin bodies include:
Organ of Zuckerkandl (near aortic bifurcation)
Carotid body
Aortic and sympathetic paraganglia
These structures help regulate vascular tone in fetal life and early infancy.
Each suprarenal gland is a retroperitoneal endocrine organ lying on the upper pole of the kidney.
Right gland → smaller, pyramidal; Left gland → larger, crescentic.
Both glands are enclosed within the renal fascia, separated from the kidney by a fibrous septum.
Cortex (mesodermal) and medulla (neural crest) have dual embryological origin.
The cortex secretes steroid hormones:
Zona glomerulosa → aldosterone
Zona fasciculata → cortisol
Zona reticularis → androgens
The medulla secretes catecholamines (adrenaline and noradrenaline).
The cortex is controlled by pituitary ACTH; the medulla by sympathetic preganglionic fibers.
Each gland receives three arteries — superior (from inferior phrenic), middle (from aorta), inferior (from renal artery).
Each gland has a single vein —
Right → inferior vena cava
Left → left renal vein
Venous blood from cortex flows through the medulla → provides steroids necessary for adrenaline synthesis.
Lymph drains to lateral aortic and renal lymph nodes.
Chromaffin cells are modified sympathetic neurons showing brown color with chromic salts.
Organ of Zuckerkandl (near aortic bifurcation) is the largest extra-adrenal chromaffin body.
The glands are essential for life — total removal leads to death unless hormone replacement is given.
Tumors of medulla → pheochromocytoma, producing paroxysmal hypertension.
Overactivity of cortex → Cushing’s or Conn’s syndrome; underactivity → Addison’s disease.
Addison’s Disease (Adrenal Insufficiency)
Destruction or atrophy of adrenal cortex.
Features: Hypotension, fatigue, skin pigmentation, salt loss, and weight loss.
Cushing’s Syndrome
Overproduction of cortisol due to adrenal or pituitary tumor.
Features: Moon face, truncal obesity, hypertension, osteoporosis, diabetes.
Conn’s Syndrome (Primary Hyperaldosteronism)
Excess aldosterone secretion.
Features: Hypertension, hypokalemia, muscle weakness, metabolic alkalosis.
Pheochromocytoma
Tumor of adrenal medulla.
Secretes excess catecholamines → paroxysmal hypertension, sweating, tachycardia, headache.
Waterhouse–Friderichsen Syndrome
Acute adrenal hemorrhage secondary to meningococcal septicemia.
Leads to circulatory collapse and death if untreated.
Congenital Adrenal Hyperplasia (CAH)
Enzyme deficiency (most commonly 21-hydroxylase).
Leads to androgen excess → virilization of females, salt loss.
Adrenal Crisis
Acute failure of adrenals due to stress, infection, or sudden steroid withdrawal.
Manifests as hypotension, hypoglycemia, and shock.
Adrenal Incidentaloma
Benign adrenal mass discovered incidentally on imaging; may secrete hormones.
Ectopic Adrenal Tissue
Small accessory adrenal rests found along the gonadal descent path.
Adrenal Cysts or Hemorrhage in Newborn
Due to birth trauma or hypoxia; may mimic abdominal tumor.
Adrenal Metastasis
Common secondary site for carcinoma (especially lung and breast).
Addisonian Crisis
Acute adrenal insufficiency precipitated by stress in a chronically deficient patient.
Chromaffinoma (Extra-Adrenal Pheochromocytoma)
Arises from paraganglia (e.g., organ of Zuckerkandl).
ACTH-Dependent Cushing’s Disease
Pituitary overproduction of ACTH causing bilateral cortical hyperplasia.
Adrenogenital Syndrome
Congenital enzyme defect → excessive androgen secretion → precocious puberty in boys, masculinization in girls.
Adrenal Calcification
Seen in tuberculosis and old hemorrhage.
Hyperpigmentation in Addison’s Disease
Due to increased ACTH stimulating melanocytes.
Adrenalectomy Considerations
Bilateral removal requires lifelong hormone replacement; right gland more difficult to remove due to short vein.
Functional Zuckerkandl Tumor
Extra-adrenal paraganglioma secreting catecholamines.
Steroid Therapy Suppression
Long-term exogenous steroids suppress ACTH and cause cortical atrophy → risk of adrenal crisis if suddenly stopped.
They lie on the upper poles of the kidneys, behind the peritoneum, enclosed within the renal fascia, one on each side of the vertebral column.
Right gland: Pyramidal or triangular.
Left gland: Crescentic or semilunar.
Anterior: Liver and inferior vena cava.
Posterior: Diaphragm.
Medial: Inferior vena cava.
Anterior: Stomach, pancreas, spleen (through omental bursa).
Posterior: Diaphragm.
Medial: Aorta.
True capsule: Condensed connective tissue.
False capsule: Formed by renal fascia and perinephric fat.
Cortex: From mesoderm (coelomic epithelium).
Medulla: From neural crest cells.
It is both an endocrine organ and a modified sympathetic ganglion.
Cortex → secretes steroid hormones.
Medulla → secretes catecholamines.
Zona glomerulosa – secretes aldosterone.
Zona fasciculata – secretes cortisol.
Zona reticularis – secretes androgens.
Secretes adrenaline and noradrenaline, which increase heart rate, BP, and blood glucose during stress (“fight or flight” response).
Modified postganglionic sympathetic neurons present in the medulla and paraganglia, which secrete catecholamines and stain brown with chromic salts.
Brown staining of chromaffin cells due to oxidation of catecholamines when treated with chromic salts.
Each gland receives three arteries:
Superior suprarenal – from inferior phrenic artery.
Middle suprarenal – from abdominal aorta.
Inferior suprarenal – from renal artery.
Right suprarenal vein → inferior vena cava.
Left suprarenal vein → left renal vein.
To lateral aortic (para-aortic) and renal lymph nodes.
Cortex: Controlled hormonally by ACTH.
Medulla: Supplied by preganglionic sympathetic fibers (T10–L1) through splanchnic nerves.
Aldosterone: Regulates sodium and water balance.
Cortisol: Increases blood glucose, reduces inflammation.
Androgens: Contribute to secondary sexual characters.
Adrenaline and noradrenaline, collectively called catecholamines.
Medulla secretes hormones directly into blood.
Sympathetic ganglia transmit impulses via axons.
Cushing’s syndrome – cortisol excess.
Conn’s syndrome – aldosterone excess.
Adrenogenital syndrome – androgen excess.
Addison’s disease – failure of cortex leading to pigmentation, hypotension, and salt loss.
Pheochromocytoma – excess catecholamine secretion → episodic hypertension, tachycardia, sweating, headache.
It is very short and opens directly into IVC → prone to tearing during surgery.
Because of its semilunar shape and broad contact with stomach and pancreas.
Bilateral removal causes death unless replaced by steroid therapy.
Cortisol from the cortex induces the enzyme phenylethanolamine-N-methyltransferase (PNMT) needed to convert noradrenaline to adrenaline.
Regulates sodium retention, potassium excretion, and helps maintain blood pressure.
Promotes gluconeogenesis, suppresses inflammation, maintains BP and stress response.
A large extra-adrenal chromaffin body near the aortic bifurcation; active in fetal life.
Genetic enzyme deficiency (commonly 21-hydroxylase) causing androgen excess and ambiguous genitalia in females.
Acute adrenal hemorrhage in meningococcal septicemia causing shock and adrenal failure.
Left suprarenal vein.
The cortex (especially zona fasciculata and zona reticularis).
Organ of Zuckerkandl near the aortic bifurcation.
Cortex: Rich in lipid (cholesterol, phospholipids).
Medulla: Rich in chromaffin granules containing catecholamines.
Arteries form a subcapsular plexus → capillaries for cortex and medulla → central vein.
Used to identify catecholamine-producing cells (diagnostic feature).
Failure of adrenal cortex development → adrenal insufficiency in infancy.
Stress stimulates ACTH → increased cortisol and catecholamine secretion (fight or flight).
Derived from sympathetic neural crest cells.
Because absence of adrenal cortical hormones leads to death within days due to electrolyte imbalance and circulatory collapse.
A. In front of kidneys
B. On the upper poles of kidneys ✅
C. Behind kidneys
D. Below kidneys
A. Crescentic
B. Oval
C. Pyramidal ✅
D. Triangular and elongated
A. Pyramidal
B. Conical
C. Crescentic ✅
D. Oval
A. Peritoneum
B. Renal fascia (Gerota’s fascia) ✅
C. Fascia transversalis
D. Parietal peritoneum
A. Endoderm
B. Ectoderm
C. Mesoderm ✅
D. Neural crest
A. Mesoderm
B. Endoderm
C. Neural crest (ectodermal) ✅
D. Mesonephric duct
A. Cortex ✅
B. Medulla
C. Capsule
D. Both cortex and medulla
A. Cortex
B. Medulla ✅
C. Capsule
D. Both
A. Zona fasciculata
B. Zona reticularis
C. Zona glomerulosa ✅
D. Medulla
A. Zona glomerulosa
B. Zona fasciculata ✅
C. Zona reticularis
D. Medulla
A. Hypothalamus directly
B. Pituitary ACTH ✅
C. Sympathetic nerves
D. Parasympathetic nerves
A. Preganglionic sympathetic fibers (T10–L1) ✅
B. ACTH
C. Parasympathetic fibers
D. Somatic nerves
A. Cortical cells
B. Medullary cells ✅
C. Zona fasciculata
D. Zona reticularis
A. Aldosterone
B. Cortisol
C. Adrenaline ✅
D. Insulin
A. Aldosterone
B. Cortisol
C. Adrenaline ✅
D. Androgen
A. ACTH
B. Cortisol (PNMT induction) ✅
C. Adrenalinase
D. Dopamine
A. Superior adrenal artery
B. Middle adrenal artery
C. Inferior adrenal artery
D. All of the above ✅
A. Renal vein
B. Inferior vena cava ✅
C. Hepatic vein
D. Azygos vein
A. Inferior vena cava
B. Left renal vein ✅
C. Left gonadal vein
D. Portal vein
A. Internal iliac nodes
B. Inguinal nodes
C. Lateral aortic (para-aortic) nodes ✅
D. Mesenteric nodes
A. Cortisol
B. Aldosterone ✅
C. Adrenaline
D. Noradrenaline
A. Aldosterone excess
B. Cortisol excess ✅
C. Catecholamine deficiency
D. Cortisol deficiency
A. Excess cortisol
B. Excess aldosterone
C. Deficiency of adrenal cortical hormones ✅
D. Pheochromocytoma
A. Cortisol excess
B. Androgen excess
C. Aldosterone excess ✅
D. Noradrenaline deficiency
A. Cortex
B. Capsule
C. Medulla ✅
D. Zona fasciculata
A. Medullary tumor
B. Adrenal hemorrhage in meningococcal infection ✅
C. Cortical tumor
D. Pituitary hyperplasia
A. Adrenaline
B. Cortisol and aldosterone ✅
C. Androgens
D. ACTH
A. Pancreatic structure
B. Extra-adrenal chromaffin body near aortic bifurcation ✅
C. Adrenal cortex
D. Paraganglion of vagus
A. Zona glomerulosa
B. Zona fasciculata ✅
C. Zona reticularis
D. Capsule
A. Adrenal cortex ✅
B. Medulla
C. Chromaffin tissue
D. Organ of Zuckerkandl
A. Inferior phrenic
B. Aorta
C. Renal
D. Gonadal ✅
A. It drains into hepatic vein
B. It drains directly into IVC ✅
C. It crosses the aorta
D. It drains into portal vein
A. Adrenal medulla
B. Sympathetic ganglion
C. Adrenal cortex ✅
D. Chromaffin cells
A. Parasympathetic ganglion
B. Sympathetic ganglion ✅
C. Somatic motor nucleus
D. None
A. Cortisol deficiency
B. Increased ACTH stimulating melanocytes ✅
C. High aldosterone
D. Catecholamine excess
A. 11-β-hydroxylase
B. 21-hydroxylase ✅
C. 17-hydroxylase
D. 3-β-dehydrogenase
A. Cortisol excess
B. Adrenal insufficiency in infancy ✅
C. Androgen excess
D. None
A. Neural crest
B. Endoderm
C. Mesodermal coelomic epithelium ✅
D. Mesonephric duct
A. Adrenal cortex
B. Adrenal medulla ✅
C. Zona fasciculata
D. Sympathetic ganglion
A. Aldosterone
B. Cortisol ✅
C. ADH
D. Insulin
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