LocationLocationLocationLocation A retroperitoneal gland, lies at the A retroperitoneal gland, lies at the

superior pole of the kidney, embedded superior pole of the kidney, embedded in adipose tissue.in adipose tissue.

The right gland is pyramidal in shape The right gland is pyramidal in shape while the left one is crescent-shaped.while the left one is crescent-shaped.

Its dimensions are 1x2x5 cm and its Its dimensions are 1x2x5 cm and its weight is 7-10 gm.weight is 7-10 gm.

Supplied by 3 arteries and drained by Supplied by 3 arteries and drained by one vein.one vein.

A retroperitoneal gland, lies at the A retroperitoneal gland, lies at the superior pole of the kidney, embedded superior pole of the kidney, embedded in adipose tissue.in adipose tissue.

The right gland is pyramidal in shape The right gland is pyramidal in shape while the left one is crescent-shaped.while the left one is crescent-shaped.

Its dimensions are 1x2x5 cm and its Its dimensions are 1x2x5 cm and its weight is 7-10 gm.weight is 7-10 gm.

Supplied by 3 arteries and drained by Supplied by 3 arteries and drained by one vein.one vein.

Connective Tissue Connective Tissue StromaStromaConnective Tissue Connective Tissue StromaStroma

Each gland is surrounded by thick Each gland is surrounded by thick connective tissue connective tissue capsulecapsule containing containing large amounts of adipose tissue.large amounts of adipose tissue.

The capsule sends The capsule sends septasepta between the between the parenchyma of the gland accompanied parenchyma of the gland accompanied by blood vessels and nerves.by blood vessels and nerves.

Parenchymal cells are supported by Parenchymal cells are supported by reticular fibers.reticular fibers.

Each gland is surrounded by thick Each gland is surrounded by thick connective tissue connective tissue capsulecapsule containing containing large amounts of adipose tissue.large amounts of adipose tissue.

The capsule sends The capsule sends septasepta between the between the parenchyma of the gland accompanied parenchyma of the gland accompanied by blood vessels and nerves.by blood vessels and nerves.

Parenchymal cells are supported by Parenchymal cells are supported by reticular fibers.reticular fibers.

Blood supply of the Blood supply of the glandglandBlood supply of the Blood supply of the glandgland

It has one of the richest blood supply of It has one of the richest blood supply of the body.the body.

Supplied by three arteries:Supplied by three arteries:– SuperiorSuperior suprarenal artery from inferior suprarenal artery from inferior

phrenic artery.phrenic artery.– MiddleMiddle suprarenal artery from aorta. suprarenal artery from aorta.– InferiorInferior suprarenal artery from renal artery. suprarenal artery from renal artery.

Drained by one vein:Drained by one vein:– Suprarenal vein Suprarenal vein Inferior venal cava (right Inferior venal cava (right

side) and left renal vein (left side).side) and left renal vein (left side).

It has one of the richest blood supply of It has one of the richest blood supply of the body.the body.

Supplied by three arteries:Supplied by three arteries:– SuperiorSuperior suprarenal artery from inferior suprarenal artery from inferior

phrenic artery.phrenic artery.– MiddleMiddle suprarenal artery from aorta. suprarenal artery from aorta.– InferiorInferior suprarenal artery from renal artery. suprarenal artery from renal artery.

Drained by one vein:Drained by one vein:– Suprarenal vein Suprarenal vein Inferior venal cava (right Inferior venal cava (right

side) and left renal vein (left side).side) and left renal vein (left side).

Parenchyma of the Parenchyma of the glandglandParenchyma of the Parenchyma of the glandgland Divides into two parts; Divides into two parts; cortexcortex (80 % of (80 % of

the gland and the gland and medullamedulla (20 %) which (20 %) which are completely different in are completely different in embryological, histological and embryological, histological and functional aspects.functional aspects.

Cortical cellsCortical cells develop from mesoderm develop from mesoderm and secrete corticosteroid hormones.and secrete corticosteroid hormones.

MedullaMedulla originates from the originates from the ectodermal neural crest cell and ectodermal neural crest cell and secretes catecholamines.secretes catecholamines.

Divides into two parts; Divides into two parts; cortexcortex (80 % of (80 % of the gland and the gland and medullamedulla (20 %) which (20 %) which are completely different in are completely different in embryological, histological and embryological, histological and functional aspects.functional aspects.

Cortical cellsCortical cells develop from mesoderm develop from mesoderm and secrete corticosteroid hormones.and secrete corticosteroid hormones.

MedullaMedulla originates from the originates from the ectodermal neural crest cell and ectodermal neural crest cell and secretes catecholamines.secretes catecholamines.

Blood circulationBlood circulationBlood circulationBlood circulation

Arteries give rise to subcapsular Arteries give rise to subcapsular plexus which gives:plexus which gives:– Short cortical arteriesShort cortical arteries network of network of

sinusoidal fenestrated capillaries sinusoidal fenestrated capillaries venous plexus venous plexus small venules small venules suprarenal medulla suprarenal medulla suprarenal suprarenal vein.vein.

– Long cortical arteriesLong cortical arteries medulla to medulla to form network of capillaries form network of capillaries renal renal vein.vein.

Arteries give rise to subcapsular Arteries give rise to subcapsular plexus which gives:plexus which gives:– Short cortical arteriesShort cortical arteries network of network of

sinusoidal fenestrated capillaries sinusoidal fenestrated capillaries venous plexus venous plexus small venules small venules suprarenal medulla suprarenal medulla suprarenal suprarenal vein.vein.

– Long cortical arteriesLong cortical arteries medulla to medulla to form network of capillaries form network of capillaries renal renal vein.vein.

Suprarenal cortexSuprarenal cortexSuprarenal cortexSuprarenal cortex

Synthesizes and secretes steroid Synthesizes and secretes steroid (corticosteroid) hormones which (corticosteroid) hormones which are derived from cholesterol.are derived from cholesterol.

Derived from mesoderm.Derived from mesoderm. Histologically, divided into three Histologically, divided into three

concentric zones: zona concentric zones: zona glomerulosa, zona fasciculata and glomerulosa, zona fasciculata and zona reticularis.zona reticularis.

Synthesizes and secretes steroid Synthesizes and secretes steroid (corticosteroid) hormones which (corticosteroid) hormones which are derived from cholesterol.are derived from cholesterol.

Derived from mesoderm.Derived from mesoderm. Histologically, divided into three Histologically, divided into three

concentric zones: zona concentric zones: zona glomerulosa, zona fasciculata and glomerulosa, zona fasciculata and zona reticularis.zona reticularis.

Zona glomerulosaZona glomerulosaZona glomerulosaZona glomerulosa

Forms the outer layer of the suprarenal Forms the outer layer of the suprarenal cortex and represent 13 % of the total cortex and represent 13 % of the total volume of the gland.volume of the gland.

Consists of cords and clusters of small Consists of cords and clusters of small columnar or pyramidal cells.columnar or pyramidal cells.

These cells have small dark nuclei, These cells have small dark nuclei, acidophilic cytoplasm containing: acidophilic cytoplasm containing: numerous SER, short mitochondria with numerous SER, short mitochondria with shelf-like cristae, well-developed Golgi shelf-like cristae, well-developed Golgi complex, abundant RER, free ribosomes complex, abundant RER, free ribosomes and lipid droplets and short microvilli.and lipid droplets and short microvilli.

Forms the outer layer of the suprarenal Forms the outer layer of the suprarenal cortex and represent 13 % of the total cortex and represent 13 % of the total volume of the gland.volume of the gland.

Consists of cords and clusters of small Consists of cords and clusters of small columnar or pyramidal cells.columnar or pyramidal cells.

These cells have small dark nuclei, These cells have small dark nuclei, acidophilic cytoplasm containing: acidophilic cytoplasm containing: numerous SER, short mitochondria with numerous SER, short mitochondria with shelf-like cristae, well-developed Golgi shelf-like cristae, well-developed Golgi complex, abundant RER, free ribosomes complex, abundant RER, free ribosomes and lipid droplets and short microvilli.and lipid droplets and short microvilli.

Function of zona Function of zona glomerulosaglomerulosaFunction of zona Function of zona glomerulosaglomerulosa

Secretes meniralocorticoids (e.g. Secretes meniralocorticoids (e.g. aldosterone and aldosterone and deoxycorticosterone).deoxycorticosterone).

This hormone This hormone plasma sodium plasma sodium concentration by concentration by its reabsorption its reabsorption in distal convoluted tubules in in distal convoluted tubules in kidneys and kidneys and its secretion in sweat its secretion in sweat and salivary glands.and salivary glands.

Its synthesis and secretion is under Its synthesis and secretion is under stimulation of angiotensin II.stimulation of angiotensin II.

Secretes meniralocorticoids (e.g. Secretes meniralocorticoids (e.g. aldosterone and aldosterone and deoxycorticosterone).deoxycorticosterone).

This hormone This hormone plasma sodium plasma sodium concentration by concentration by its reabsorption its reabsorption in distal convoluted tubules in in distal convoluted tubules in kidneys and kidneys and its secretion in sweat its secretion in sweat and salivary glands.and salivary glands.

Its synthesis and secretion is under Its synthesis and secretion is under stimulation of angiotensin II.stimulation of angiotensin II.

Zona fasciculataZona fasciculataZona fasciculataZona fasciculata

Forms the intermediate layer of the suprarenal Forms the intermediate layer of the suprarenal cortex and represent 80 % of the total volume of cortex and represent 80 % of the total volume of the gland.the gland.

Consists of columns of polyhedral cells arranged Consists of columns of polyhedral cells arranged longitudinally, with capillary sinusoids lying longitudinally, with capillary sinusoids lying between them.between them.

These cells are larger than the zona glomerulosa These cells are larger than the zona glomerulosa cells, with slight acidophilic cytoplasm which cells, with slight acidophilic cytoplasm which appears vacuolated because it has lipid droplets.appears vacuolated because it has lipid droplets.

The cells have spherical mitochondria, extensive The cells have spherical mitochondria, extensive SER, some RER, lysosomes and lipofuscin SER, some RER, lysosomes and lipofuscin pigmentspigments

Forms the intermediate layer of the suprarenal Forms the intermediate layer of the suprarenal cortex and represent 80 % of the total volume of cortex and represent 80 % of the total volume of the gland.the gland.

Consists of columns of polyhedral cells arranged Consists of columns of polyhedral cells arranged longitudinally, with capillary sinusoids lying longitudinally, with capillary sinusoids lying between them.between them.

These cells are larger than the zona glomerulosa These cells are larger than the zona glomerulosa cells, with slight acidophilic cytoplasm which cells, with slight acidophilic cytoplasm which appears vacuolated because it has lipid droplets.appears vacuolated because it has lipid droplets.

The cells have spherical mitochondria, extensive The cells have spherical mitochondria, extensive SER, some RER, lysosomes and lipofuscin SER, some RER, lysosomes and lipofuscin pigmentspigments

Function of zona Function of zona fasciculatafasciculataFunction of zona Function of zona fasciculatafasciculata Secretes glucocorticoids (e.g. cortisol, Secretes glucocorticoids (e.g. cortisol,

cortisone and corticosterone).cortisone and corticosterone). These hormones affect carbohydrate, These hormones affect carbohydrate,

fat and protein metabolism resulting fat and protein metabolism resulting in increase in glucose and amino acids in increase in glucose and amino acids levels and movement of fat.levels and movement of fat.

They also suppress inflammatory They also suppress inflammatory responses in allergic reactions.responses in allergic reactions.

Their synthesis and secretion is under Their synthesis and secretion is under stimulation of ACTH of pituitary gland.stimulation of ACTH of pituitary gland.

Secretes glucocorticoids (e.g. cortisol, Secretes glucocorticoids (e.g. cortisol, cortisone and corticosterone).cortisone and corticosterone).

These hormones affect carbohydrate, These hormones affect carbohydrate, fat and protein metabolism resulting fat and protein metabolism resulting in increase in glucose and amino acids in increase in glucose and amino acids levels and movement of fat.levels and movement of fat.

They also suppress inflammatory They also suppress inflammatory responses in allergic reactions.responses in allergic reactions.

Their synthesis and secretion is under Their synthesis and secretion is under stimulation of ACTH of pituitary gland.stimulation of ACTH of pituitary gland.

Zona reticularisZona reticularisZona reticularisZona reticularis Forms the inner layer of the Forms the inner layer of the

suprarenal cortex and represent 7 % suprarenal cortex and represent 7 % of the total volume of the gland.of the total volume of the gland.

Consists of anastomosing cords of Consists of anastomosing cords of small polyhedral cells.small polyhedral cells.

These cells resemble those of zona These cells resemble those of zona fasciculata but smaller in size, having fasciculata but smaller in size, having darkly stained acidophilic cytoplasm darkly stained acidophilic cytoplasm with fewer lipid droplets and large with fewer lipid droplets and large amounts of lipofuscin pigments.amounts of lipofuscin pigments.

Forms the inner layer of the Forms the inner layer of the suprarenal cortex and represent 7 % suprarenal cortex and represent 7 % of the total volume of the gland.of the total volume of the gland.

Consists of anastomosing cords of Consists of anastomosing cords of small polyhedral cells.small polyhedral cells.

These cells resemble those of zona These cells resemble those of zona fasciculata but smaller in size, having fasciculata but smaller in size, having darkly stained acidophilic cytoplasm darkly stained acidophilic cytoplasm with fewer lipid droplets and large with fewer lipid droplets and large amounts of lipofuscin pigments.amounts of lipofuscin pigments.

Function of zona Function of zona reticularisreticularisFunction of zona Function of zona reticularisreticularis Secretes androgens (e.g. dehydro-Secretes androgens (e.g. dehydro-

epiandrosterone).epiandrosterone). These hormones have weak These hormones have weak

masculinizing effect which is masculinizing effect which is negligible under normal condition.negligible under normal condition.

Their synthesis and secretion is Their synthesis and secretion is under stimulation of ACTH of under stimulation of ACTH of pituitary gland.pituitary gland.

Secretes androgens (e.g. dehydro-Secretes androgens (e.g. dehydro-epiandrosterone).epiandrosterone).

These hormones have weak These hormones have weak masculinizing effect which is masculinizing effect which is negligible under normal condition.negligible under normal condition.

Their synthesis and secretion is Their synthesis and secretion is under stimulation of ACTH of under stimulation of ACTH of pituitary gland.pituitary gland.

Suprarenal medullaSuprarenal medullaSuprarenal medullaSuprarenal medulla

Occupies the central portion of Occupies the central portion of the suprarenal glands and is the suprarenal glands and is totally covered by the cortical totally covered by the cortical part.part.

Develops from the ectodermal Develops from the ectodermal neural crest cells.neural crest cells.

Consists of two cell populations: Consists of two cell populations: chromaffin cells and sympathetic chromaffin cells and sympathetic ganglion cells.ganglion cells.

Occupies the central portion of Occupies the central portion of the suprarenal glands and is the suprarenal glands and is totally covered by the cortical totally covered by the cortical part.part.

Develops from the ectodermal Develops from the ectodermal neural crest cells.neural crest cells.

Consists of two cell populations: Consists of two cell populations: chromaffin cells and sympathetic chromaffin cells and sympathetic ganglion cells.ganglion cells.

Chromaffin cellsChromaffin cellsChromaffin cellsChromaffin cells

Large epithelioid cells, arranged in Large epithelioid cells, arranged in clusters or short cords.clusters or short cords.

Contain catecholamines in membrane-Contain catecholamines in membrane-bound vesicles which are released by bound vesicles which are released by exocytosis under sympathetic exocytosis under sympathetic stimulation.stimulation.

They are of two types: epinephrine and They are of two types: epinephrine and norepinephrine secreting cells.norepinephrine secreting cells.

The norepinephrine granules are more The norepinephrine granules are more dense than the epinephrine granules.dense than the epinephrine granules.

Large epithelioid cells, arranged in Large epithelioid cells, arranged in clusters or short cords.clusters or short cords.

Contain catecholamines in membrane-Contain catecholamines in membrane-bound vesicles which are released by bound vesicles which are released by exocytosis under sympathetic exocytosis under sympathetic stimulation.stimulation.

They are of two types: epinephrine and They are of two types: epinephrine and norepinephrine secreting cells.norepinephrine secreting cells.

The norepinephrine granules are more The norepinephrine granules are more dense than the epinephrine granules.dense than the epinephrine granules.

Function of Function of medullamedullaFunction of Function of medullamedulla Synthesis and release of adrenaline Synthesis and release of adrenaline

and noradrenaline.and noradrenaline. Respiratory rate with Respiratory rate with

bronchodilatation.bronchodilatation. Heart rate and cardiac output.Heart rate and cardiac output. Blood pressure.Blood pressure. lipolysis and glycogenolysis.lipolysis and glycogenolysis. Action of what is called Action of what is called ““fight and fight and

flightflight””

Synthesis and release of adrenaline Synthesis and release of adrenaline and noradrenaline.and noradrenaline.

Respiratory rate with Respiratory rate with bronchodilatation.bronchodilatation.

Heart rate and cardiac output.Heart rate and cardiac output. Blood pressure.Blood pressure. lipolysis and glycogenolysis.lipolysis and glycogenolysis. Action of what is called Action of what is called ““fight and fight and

flightflight””

Some Clinical Some Clinical CorrelationsCorrelationsSome Clinical Some Clinical CorrelationsCorrelations

AddisonAddison’’s diseases disease:: secretion of adrenocortical secretion of adrenocortical hormones because of hormones because of destruction of adrenal cortex.destruction of adrenal cortex.

–Caused by TB, autoimmune Caused by TB, autoimmune disease or any chronic disease or any chronic disease.disease.

–Fatal disease.Fatal disease.

AddisonAddison’’s diseases disease:: secretion of adrenocortical secretion of adrenocortical hormones because of hormones because of destruction of adrenal cortex.destruction of adrenal cortex.

–Caused by TB, autoimmune Caused by TB, autoimmune disease or any chronic disease or any chronic disease.disease.

–Fatal disease.Fatal disease.

CushingCushing’’s disease:s disease:– Due to small tumor in the Due to small tumor in the

anterior pituitary leading to anterior pituitary leading to secretion of ACTH, which causes secretion of ACTH, which causes enlargement and hypertrophy of enlargement and hypertrophy of suprarenal cortex which secretes suprarenal cortex which secretes more cortisol that causes obesity, more cortisol that causes obesity, impotance in males and impotance in males and amenorrhea in females.amenorrhea in females.

CushingCushing’’s disease:s disease:– Due to small tumor in the Due to small tumor in the

anterior pituitary leading to anterior pituitary leading to secretion of ACTH, which causes secretion of ACTH, which causes enlargement and hypertrophy of enlargement and hypertrophy of suprarenal cortex which secretes suprarenal cortex which secretes more cortisol that causes obesity, more cortisol that causes obesity, impotance in males and impotance in males and amenorrhea in females.amenorrhea in females.

Some Clinical Some Clinical CorrelationsCorrelationsSome Clinical Some Clinical CorrelationsCorrelations

LocationLocationLocationLocation A small conical-shaped A small conical-shaped

endocrine gland lying in the endocrine gland lying in the midline attached to the roof midline attached to the roof of the diencephalon of the of the diencephalon of the brain.brain.

Its dimensions are 7 x 4 mm Its dimensions are 7 x 4 mm and its weight is 120 mg.and its weight is 120 mg.

A small conical-shaped A small conical-shaped endocrine gland lying in the endocrine gland lying in the midline attached to the roof midline attached to the roof of the diencephalon of the of the diencephalon of the brain.brain.

Its dimensions are 7 x 4 mm Its dimensions are 7 x 4 mm and its weight is 120 mg.and its weight is 120 mg.

Connective Tissue Connective Tissue StromaStromaConnective Tissue Connective Tissue StromaStroma

The gland is covered by pia The gland is covered by pia mater which forms its capsule, mater which forms its capsule, that sends connective tissue that sends connective tissue septa dividing the gland into septa dividing the gland into complete lobules.complete lobules.

Blood vessels and sympathetic Blood vessels and sympathetic nerves enter the gland via the nerves enter the gland via the connective tissue septa.connective tissue septa.

The gland is covered by pia The gland is covered by pia mater which forms its capsule, mater which forms its capsule, that sends connective tissue that sends connective tissue septa dividing the gland into septa dividing the gland into complete lobules.complete lobules.

Blood vessels and sympathetic Blood vessels and sympathetic nerves enter the gland via the nerves enter the gland via the connective tissue septa.connective tissue septa.

Parenchymal cellsParenchymal cellsParenchymal cellsParenchymal cells

Two types of cells present in the pineal Two types of cells present in the pineal gland the first is gland the first is pinealocytespinealocytes::– They form the majority of cells.They form the majority of cells.

– Slightly basophilic cells, having spherical Slightly basophilic cells, having spherical lobulated nucleus with one nucleolus. The lobulated nucleus with one nucleolus. The cytoplasm has SER, RER, small Golgi apparatus, cytoplasm has SER, RER, small Golgi apparatus, numerous mitochondria, small secretory numerous mitochondria, small secretory vesicles containing electron-dense core.vesicles containing electron-dense core.

– They have one or two long processes with They have one or two long processes with terminal dilatation near other cells or terminal dilatation near other cells or capillaries.capillaries.

Two types of cells present in the pineal Two types of cells present in the pineal gland the first is gland the first is pinealocytespinealocytes::– They form the majority of cells.They form the majority of cells.

– Slightly basophilic cells, having spherical Slightly basophilic cells, having spherical lobulated nucleus with one nucleolus. The lobulated nucleus with one nucleolus. The cytoplasm has SER, RER, small Golgi apparatus, cytoplasm has SER, RER, small Golgi apparatus, numerous mitochondria, small secretory numerous mitochondria, small secretory vesicles containing electron-dense core.vesicles containing electron-dense core.

– They have one or two long processes with They have one or two long processes with terminal dilatation near other cells or terminal dilatation near other cells or capillaries.capillaries.

Glial (interstitial) cells:Glial (interstitial) cells:– They form a network around They form a network around

the pinealocytes, and the pinealocytes, and considered as astrocytes.considered as astrocytes.

– They have small dark nuclei, They have small dark nuclei, well-developed RER, glycogen well-developed RER, glycogen droplets and long cellular droplets and long cellular processes.processes.

Glial (interstitial) cells:Glial (interstitial) cells:– They form a network around They form a network around

the pinealocytes, and the pinealocytes, and considered as astrocytes.considered as astrocytes.

– They have small dark nuclei, They have small dark nuclei, well-developed RER, glycogen well-developed RER, glycogen droplets and long cellular droplets and long cellular processes.processes.

Parenchymal cellsParenchymal cellsParenchymal cellsParenchymal cells

Brain SandsBrain SandsBrain SandsBrain Sands

The pineal gland contains The pineal gland contains concentrations of calcium phosphate concentrations of calcium phosphate and carbonate deposited in and carbonate deposited in concentric rings around an organic concentric rings around an organic matrix.matrix.

They appears in childhood and They appears in childhood and increase with age.increase with age.

Their function is unknown but they Their function is unknown but they are used as a radiological diagnostic are used as a radiological diagnostic tool.tool.

The pineal gland contains The pineal gland contains concentrations of calcium phosphate concentrations of calcium phosphate and carbonate deposited in and carbonate deposited in concentric rings around an organic concentric rings around an organic matrix.matrix.

They appears in childhood and They appears in childhood and increase with age.increase with age.

Their function is unknown but they Their function is unknown but they are used as a radiological diagnostic are used as a radiological diagnostic tool.tool.

Function of pineal Function of pineal glandglandFunction of pineal Function of pineal glandgland Secretion of melatonin, serotonin Secretion of melatonin, serotonin

and indalomine.and indalomine. It has circadian rhythm (melatonin It has circadian rhythm (melatonin

in darkness and in darkness and during day light). during day light). Retina Retina sympathetic innervation of sympathetic innervation of

the gland the gland stimulate secretion. stimulate secretion. Melatonin influence secretion of Melatonin influence secretion of

other endocrine glands through other endocrine glands through hypothalamus.hypothalamus.

Secretion of melatonin, serotonin Secretion of melatonin, serotonin and indalomine.and indalomine.

It has circadian rhythm (melatonin It has circadian rhythm (melatonin in darkness and in darkness and during day light). during day light).

Retina Retina sympathetic innervation of sympathetic innervation of the gland the gland stimulate secretion. stimulate secretion.

Melatonin influence secretion of Melatonin influence secretion of other endocrine glands through other endocrine glands through hypothalamus.hypothalamus.

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