03 Adrenal Gland

Adrenal gland blood supply

Structures

Outer capsule, cortex, and medulla..

  • Cortex: makes the corticoids
  • Medulla is like a massive nerve. Also secretes dopamine

Germ Cell Layers:..

Chromaffin Cells

Neuroendocrine cells found mostly in the medulla of the adrenal glands that secretes E and NE.

Neural crest derived..

Zones:..

  • mnemonic: GFR

Adrenal Gland Hormones

Zona Glomerulosa

Makes mineralcorticoids.

Desmolase

Stimulated by ACTH to make cortisol.

Aldosterone Synthase

Stimulated by Ang II to make aldosterone.

Zona Fasciculata

Makes glucocorticoids.

Zona Reticularis

Makes androgens.

17, 30 lyase double bonds at 17 position:

Mineralcorticoids

Mineral: minerals like Na/K. Corticoids: Made in the cortex

  • Increase Na channels and Na/K pumps: increase Na reabsorption, K secretion on principal cell
  • Increase H pump: increase H secretion on intercalated cell.

Glucocorticoids aka Cortisol

CBG

Circadian Rhythm

Circadian rhythm: Hormone is highest at morning to prepare for stress of the day.

Cortisol Effects

  • Cortisol goes up in time of stress. Increases BP and necessary nutrients, and shuts down everything else..

BP Effects

Immune Effects

  • Suppress because don't need immune system in stress..

  • Glucocorticoids inhibit the production of IL-2, which is important for T-cell proliferation. Thus, pharmacologic doses of glucocorticoids prevent the rejection of transplanted organs.
  • The induction of synthesis of lipocortin, a phospholipase A2 inhibitor, leads to the inhibition of leukotriene and prostaglandin production.

They exert these effects through several mechanisms:..

Glucose Effects

  • Hyperglycemia for energy needs
  • Glucocorticoids: makes glucose

Also enhances glucagon that offsets glycogen synthase effects.

  • glucagon and epinephrine good for short term stress

Fat Effects

  • Activates lipolysis for energy but stimulates fat deposition chronically.

Effects on muscles, skin, bones

  • Negative effects because don't need any of these in stress..

Striae

Purple stretch marks in dermis that can be seen due to thinning of skin. Cortisol decreases fibroblast activity.

Corticosteroid Drugs

  • oral prednisone often used for asthma, lupus, etc.
  • methylprednisolone is IV form of prednisone..

Androgens

More important in females