01 Adrenal Glands.mp4

• The adrenal glands, which are located above the kidneys, consist of an outer cortex and an inner medulla. The adrenal cortex and medulla develop and function independently from each other. The adrenal cortex originates from the mesoderm, while the adrenal medulla originates from the neural crest.
• The fully developed adrenal cortex is made up of three distinct zones: the outer zona Glomerulosa, the middle zona Fasciculata, and the inner zona Reticularis (remember it as GFR). The zona glomerulosa synthesizes mineralocorticoids, the zona fasciculata mainly produces cortisol, and the zona reticularis primarily produces androgens.
• GFR corresponds with Salt (Na), Sugar (glucocorticoids), and Sex (androgens). The deeper you go, the sweeter it gets. (:

• ACTH from the anterior pituitary boosts the secretion of cortisol and adrenal androgens from the zona fasciculata and the zona reticularis respectively, but it doesn't have a significant effect on aldosterone secretion.
• The secretion of aldosterone from the zona glomerulosa is regulated by the renin-angiotensin system.

• Pro-opiomelanocortin:

  • Anterior pituitary corticotrophes synthesize pro-opiomelanocortin, which is cleaved to give rise to multiple peptide hormones:
    1. ACTH: Stimulates the secretion of cortisol and adrenal androgens from the adrenal cortex. Cortisol suppresses the release of ACTH by acting on the hypothalamus and anterior pituitary.
    2. B-Lipotropin: Its role is not well understood. It's a precursor to B-MSH and endorphins. Endorphins may modulate the perception of pain.
  • Excessive secretion of ACTH (Addisons disease) causes skin darkening. This is due to the melanocyte-stimulating hormone (a-MSH) sequence within the ACTH molecule and the B-MSH activity of B-lipotropin.

• Adrenal gland drainage:

  • Left adrenal drains into the left adrenal vein, which then drains into the left renal vein and finally into the IVC.
  • Right adrenal drains into the right adrenal vein and then into the IVC.