Adrenal gland and paraganglia

Topic Completed: 1 March 2013

Revised: 28 May 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Adrenal gland paraganglia anatomy

Severino Rey Nodar, M.D., Ph.D.
Page views in 2018: 850
Page views in 2019 to date: 683
Cite this page: Nodar SR. Anatomy. website. Accessed August 18th, 2019.
Definition / general
  • Also called suprarenal glands
  • Responsible for release of hormones that regulate metabolism, immune system function, salt-water balance in bloodstream; also aid in body's response to stress
  • A composite of two neuroendocrine organs, the adrenal cortex (mesodermal, produces steroid hormones aldosterone, cortisol and testosterone) and adrenal medulla (neuroectodermal, produces catecholamines)

Anatomic features
  • Left and right-sided glands; left gland is crescentic and right gland is pyramidal in adults; each is 5 x 3 x 1 cm
  • On superiomedial kidneys in retroperitoneum
  • Has two main parts: cortex and medulla
  • Normal weight is 4-6 grams each gland after dissection of fat; acute stress reduces lipid content and weight; prolonged stress induces hypertrophy and hyperplasia and increases weight
  • Has complete fibrous capsule, which may merge with capsule of kidney (either gland) and liver (right sided gland)
  • Neonatal gland is dark red-brown due to congestion with no visible medullary tissue
  • Adrenal glands are supplied by aorta, inferior phrenic arteries and renal arteries; are drained by shorter right adrenal vein and longer left adrenal vein
  • Lymphatics only in capsule, not elsewhere

Adrenal cortex
Adrenal medulla
  • Has ellipsoid shape, is gray-tan and < 10% of gland volume (1% in neonates)
  • Is more prominent with cortical atrophy
  • Most of medulla is within head of gland
  • Highly vascularized
  • Is core of the adrenal gland, and is surrounded by adrenal cortex
  • Secretes approximately 20% norepinephrine (noradrenaline) and 80% epinephrine (adrenaline)
  • Its chromaffin cells, named for their characteristic brown color, are body's main source of circulating catecholamines epinephrine and norepinephrine (Wikipedia)
  • Considered a specialized sympathetic ganglion due to innervation by preganglionic nerve fibers
Diagrams / tables

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View from front

View from behind

Microscopic (histologic) images

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Normal adrenal gland

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