Anatomy of the Abdomen and Pelvis

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Adrenal (Suprarenal) Glands

Summary

The adrenal (suprarenal) glands are paired, triangular endocrine organs found on the top of the kidneys. They consist of an outer cortex and an inner medulla, and their function is the production and secretion of various vital hormones.

The kidneys, adrenal glands, and the surrounding fascia

Functions

The suprarenal glands produce two distinct groups of vital hormones:

  • Cortical hormones
    • Released from 3 layers the cortex of the adrenal gland
    • Mineralocorticoids (aldosterone)
      • Control electrolyte balance
    • Glucocorticoids (cortisol)
      • Control glucose metabolism
    • Androgens (DHE)
      • Sex hormones
  • Catecholamines
    • Released from the medulla of the adrenal gland
    • Include epinephrine (mostly) and norepinephrine
      • Released during a fight or flight response
A cross-section of the adrenal gland, with a diagram explaining the tissue areas and the hormones released (Credit: OpenStax, CC BY-SA 4.0)

Location

The suprarenal glands are associated with the superior pole of each kidney, separated from them by a thin septum, embedded within the perirenal fat, which is covered by the renal fascia.

  • Holotopy —¬†Right and left hypochondriac regions
  • Skeletopy¬†— At the level of T11-12 thoracic vertebrae
  • Syntopy:
    • The right gland is located between the right lobe of the liver and the inferior vena cava
    • The left gland is located posterior to parts of the stomach, pancreas, and in some cases the spleen

Parts and surfaces

  • The glands consist of an outer cortex and an inner medulla
  • The right gland has a pyramid shape, while the left gland is crescent-shaped and is the bigger of the two

Neurovasculature

Blood supply Venous drainage Innervation Lymphatic drainage
  • Superior adrenal (suprarenal) arteries from the inferior phrenic arteries (branches of the abdominal aorta)
  • Middle adrenal arteries from the abdominal aorta
  • Inferior adrenal arteries from the renal arteries
  • Right adrenal vein drains to the inferior vena cava
  • Left adrenal vein drains to the left renal vein (and then to the IVC)
Direct sympathetic innervation (presynaptic fibers that synapse within the adrenal glands) from T8-L1 Aortic (left) and caval (right) lymph nodes
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