Basic Functions of the Adrenal Glands Flashcards
Name the zones of the cortex from superficial to deep and their functions
Zona glomerulosa = mineralcorticoids eg. aldosterone
Zona fasiculata = glucocorticoids eg. cortisol
Zona reticularis = androgens eg. DHEA
What does the adrenal medulla do
Catecholamine synthesis
What are corticosteroids
Cholesterol derivatives
3, 6 rings + 1, 5 rings
Lipid soluble
Bind to intracellular receptors
What is hyperplasia and hypoplasia of cortex
Hyperplasia = ACTH excess Hypoplasia = ACTH deficiency
How does corticosteroids travel in serum
Bind to Corticosteroid Binding Globulin
Only free ones are bioavailable
CBG decreases with inflammation
What is sepsis
Vascular endothelium degrades
CBG found outside intravascular space
CBG cleaved so cannot bind to Cortisol
What is the primary, secondary and tertiary glands of the HPA axis
Primary = Adrenal Secondary = pituitary Tertiary = Hypothalamus
What is released by hypothalamus to stimulate ACTH production
CRH
What is stress
Sum of bodies responses to adverse stimuli
Eg. Infection, trauma, exhaustion
Loss of diurnal rhythm
Where do mineralcorticoids act
Distal convoluted tubule
What does aldosterone do
Plasma: Sodium low, potassium high
Urine: Sodium high, potassium low
What is released by the kidney when renal BP decreases
Renin
What acts on adrenals to stimulate aldosterone production
Angiotensin II
What do ACE inhibitors do
Decrease BP
Mineralcorticoid receptors can accommodate both aldosterone and cortisol. There is more cortisol in the body, why arent MR swamped with cortisol
In presence of 11 beta HSD2 active cortisol is transformed into inactive cortisone leaving MR empty
Without 11 beta HSD2 too much cortisol = Cushings
