Pituitary, Pancreas & Adrenal Glands – Gross Anatomy, Histology, Embryology & Clinical Terms

Vocabulary flashcards covering essential anatomical, histological, embryological and clinical terms related to the pituitary, pancreas and adrenal glands discussed in the lecture.

Endocrine gland

A duct-less organ that releases hormones directly into the bloodstream to act on distant target tissues.

Pituitary gland (Hypophysis)

Small bean-shaped endocrine gland suspended from the hypothalamus by the infundibulum and housed in the sella turcica.

Infundibulum

The stalk that connects the pituitary gland to the hypothalamus.

Diaphragma sellae

A dural fold that roofs the pituitary fossa and has an aperture for the infundibulum.

Sella turcica

Depression in the sphenoid bone containing the hypophyseal fossa for the pituitary.

Adenohypophysis

Anterior lobe of the pituitary composed of glandular tissue; synthesises and secretes seven hormones.

Pars distalis

Largest subdivision of the adenohypophysis (≈75%); contains chromophils and chromophobes.

Pars intermedia

Thin basophilic zone between pars distalis and pars nervosa that contains Rathke’s cleft remnants and produces small amounts of MSH.

Pars tuberalis

Sleeve-like part of adenohypophysis that surrounds the infundibulum; highly vascular and rich in gonadotrophs.

Neurohypophysis

Posterior lobe of pituitary derived from neuroectoderm; stores and releases oxytocin & ADH made in the hypothalamus.

Pars nervosa

Main storage portion of the neurohypophysis containing unmyelinated axons, Herring bodies and pituicytes.

Pituicyte

Specialised glial cell in the neurohypophysis that supports neurosecretory axons.

Herring body

Dilated terminal of a neurosecretory axon in pars nervosa storing vesicles of oxytocin or ADH.

Chromophil

Hormone-secreting cell of pars distalis that stains intensely (acidophil or basophil) and contains cytoplasmic granules.

Chromophobe

Weakly staining cell in pars distalis; includes stem, progenitor and degranulated cells.

Acidophil

Pink-staining chromophil of pars distalis; includes somatotrophs and lactotrophs.

Basophil

Bluish-purple chromophil of pars distalis; includes corticotrophs, thyrotrophs and gonadotrophs.

Somatotroph

Acidophil that secretes growth hormone (GH).

Mammotroph (Lactotroph)

Acidophil that secretes prolactin.

Corticotroph

Basophil that secretes ACTH.

Thyrotroph

Basophil that secretes thyroid-stimulating hormone (TSH).

Gonadotroph

Basophil that secretes FSH and LH.

Hypothalamic-hypophyseal portal system

Vascular link carrying hypothalamic releasing/inhibiting hormones to the anterior pituitary (primary & secondary capillary plexuses).

Hypothalamic-hypophyseal tract

Bundle of axons from supraoptic and paraventricular nuclei transporting oxytocin & ADH to the posterior pituitary.

Superior hypophyseal artery

Branch of internal carotid that supplies the median eminence, stalk and anterior pituitary.

Inferior hypophyseal artery

Branch of internal carotid that supplies the posterior pituitary.

Pituitary adenoma

Benign tumour of pituitary cells; can compress the optic chiasm causing bitemporal hemianopia.

Gigantism

Excess GH secretion before epiphyseal closure in children, producing abnormal height.

Acromegaly

Excess GH secretion after epiphyseal closure in adults, causing bone thickening of face, hands and feet.

Rathke’s pouch

Ectodermal outpouching from the roof of the embryonic stomodeum that forms the adenohypophysis.

Islets of Langerhans

Endocrine cell clusters in the pancreas that secrete insulin, glucagon, somatostatin and pancreatic polypeptide.

Alpha (α) cell

Peripheral islet cell that secretes glucagon to raise blood glucose.

Beta (β) cell

Central islet cell that secretes insulin to lower blood glucose.

Delta (δ) cell

Islet cell that secretes somatostatin, inhibiting insulin and glucagon release.

PP cell

Rare islet cell secreting pancreatic polypeptide; abundant in pancreatic head.

Pancreatic acinus

Exocrine unit of pancreas made of serous acinar cells producing digestive enzymes.

Main pancreatic duct

Duct running from tail to head of pancreas; joins the bile duct to form the hepatopancreatic ampulla.

Accessory pancreatic duct

Secondary duct draining into the minor duodenal papilla; provides alternate pancreatic juice flow.

Hepatopancreatic ampulla (Ampulla of Vater)

Confluence of bile and main pancreatic ducts opening at the major duodenal papilla.

Hepatopancreatic sphincter (Sphincter of Oddi)

Smooth muscle ring around the ampulla preventing duodenal reflux.

Sphincter of pancreatic duct

Muscular ring controlling flow of pancreatic juice through the main duct.

Uncinate process

Hook-like projection of pancreatic head that extends posterior to the superior mesenteric vessels.

Splenic artery

Tortuous branch of celiac trunk that supplies pancreatic body and tail via numerous pancreatic branches.

Anterior superior pancreaticoduodenal artery

Branch of gastroduodenal artery supplying upper anterior head of pancreas.

Posterior superior pancreaticoduodenal artery

Branch of gastroduodenal artery supplying upper posterior head of pancreas.

Anterior inferior pancreaticoduodenal artery

Branch of SMA supplying lower anterior head of pancreas.

Posterior inferior pancreaticoduodenal artery

Branch of SMA supplying lower posterior head of pancreas.

Annular pancreas

Developmental anomaly where pancreatic tissue encircles the duodenum due to abnormal ventral bud migration.

Pancreatitis

Inflammation of pancreas often triggered by blockage of the hepatopancreatic ampulla by a gallstone.

Gerota’s fascia (Renal fascia)

Fibrous envelope surrounding kidneys and adrenal glands, containing perinephric fat.

Adrenal cortex

Outer portion of adrenal gland derived from mesoderm; secretes corticosteroids and androgens.

Adrenal medulla

Inner portion of adrenal gland derived from neural crest; secretes catecholamines.

Zona glomerulosa

Outer adrenal cortical zone secreting mineralocorticoids (e.g., aldosterone).

Zona fasciculata

Middle and largest cortical zone secreting glucocorticoids (e.g., cortisol).

Zona reticularis

Inner cortical zone secreting androgens (e.g., DHEA) and small amounts of cortisol.

Mineralocorticoid

Steroid hormone (mainly aldosterone) regulating sodium and water balance.

Glucocorticoid

Steroid hormone (mainly cortisol) affecting glucose metabolism and stress response.

Gonadocorticoid

Adrenal cortical androgen such as dehydroepiandrosterone (DHEA).

Chromaffin cell

Modified post-ganglionic sympathetic neuron in adrenal medulla that secretes epinephrine or norepinephrine.

Superior suprarenal artery

Branch of inferior phrenic artery supplying adrenal gland.

Middle suprarenal artery

Branch of abdominal aorta supplying adrenal gland.

Inferior suprarenal artery

Branch of renal artery supplying adrenal gland.

Right suprarenal vein

Short vein draining right adrenal gland directly into the inferior vena cava.

Left suprarenal vein

Vein draining left adrenal gland into left renal vein via the inferior phrenic vein.

Cisterna chyli

Dilated sac at origin of thoracic duct; receives lymph from lumbar and intestinal trunks including adrenal drainage.

Greater splanchnic nerve

Preganglionic sympathetic nerve (T5-T9) conveying fibres that ultimately innervate adrenal medulla.

Pheochromocytoma

Catecholamine-secreting tumour of adrenal medulla causing paroxysmal hypertension.

Cushing’s syndrome

Clinical state of excess cortisol, commonly from adrenal cortical hyperplasia or tumours.

Capsular artery

Small branch of suprarenal arteries supplying adrenal capsule and sending cortical arterioles inward.

Cortical arteriole

Vessel that forms fenestrated sinusoids through adrenal cortex before draining into medullary capillaries.

Medullary arteriole

Artery bypassing cortex to supply adrenal medulla directly with arterial blood.

Adrenomedullary vein

Large central vein draining blood from adrenal medulla.

Mesodermal adrenal primordium

Embryonic tissue forming the adrenal cortex from mesothelial cells adjacent to urogenital ridge.

Neural crest adrenal primordium

Embryonic cells invading adrenal primordium to form chromaffin cells of medulla.

Fetal adrenal cortex

Early large acidophilic cortical layer that secretes DHEA during gestation and regresses after birth.

DHEA (Dehydroepiandrosterone)

Adrenal androgen produced by fetal cortex; converted to placental estrogens.

Bitemporal hemianopia

Loss of peripheral vision in both eyes due to optic chiasm compression, often by pituitary tumour.

Hypophyseal fossa

Depression in sella turcica housing the pituitary gland.

Cavernous sinus

Paired venous plexus lateral to pituitary containing internal carotid artery and cranial nerves III, IV, V1, V2, VI.

Basilar artery

Midline artery posterior to pituitary formed by vertebral arteries; mentioned as posterior relation.

Supraoptic nucleus

Hypothalamic nucleus producing ADH delivered to posterior pituitary.

Paraventricular nucleus

Hypothalamic nucleus producing oxytocin delivered to posterior pituitary.

Oxytocin

Posterior pituitary hormone causing uterine contraction and milk ejection.

Antidiuretic hormone (ADH, Vasopressin)

Posterior pituitary hormone increasing renal water reabsorption.

Somatomedin (IGF-1)

Liver-derived mediator of GH promoting bone and tissue growth.

Supraopticohypophyseal tract

Alternate name for hypothalamic-hypophyseal tract conveying ADH- and oxytocin-laden axons.

Transpyloric plane

Horizontal plane at L1; level of pancreas, pylorus, hilum of kidneys, etc.

Superior mesenteric vein (SMV)

Vein running posterior to neck of pancreas; joins splenic vein to form hepatic portal vein.

Splenorenal ligament

Peritoneal fold containing splenic vessels and pancreatic tail.

Splanchnic mesoderm

Embryonic tissue giving rise to connective tissue capsule of pancreas and adrenal glands.

Dorsal pancreatic bud

Embryonic bud forming body, tail and superior head of pancreas.

Ventral pancreatic bud

Embryonic bud forming uncinate process and inferior head of pancreas.

Hepatic portal vein

Formed by union of splenic vein and SMV posterior to pancreatic neck; drains GI tract to liver.