The Suprarenal (Adrenal) Glands

Key points

• • The two suprarenal (adrenal) glands sit like caps on the upper poles of the kidneys, wrapped in the same fascia but separated from the kidney by fat.
• • Each gland has two parts of different origin: an outer cortex from mesoderm and an inner medulla from neural crest, packaged together.
• • They have an unusually rich blood supply from three sources: the superior, middle and inferior suprarenal arteries.
• • Despite the many arteries, each gland is usually drained by a single vein: on the right a short vein into the inferior vena cava, and on the left a longer vein into the left renal vein.
• • The cortex makes steroid hormones - aldosterone (salt), cortisol (sugar) and adrenal androgens (sex steroids) - while the medulla makes adrenaline and noradrenaline.
• • The medulla is really a modified sympathetic ganglion, which is why it pours out adrenaline as part of the fight-or-flight response.