Summary Adrenal physiology and common pathologies

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Adrenals

Adrenal glands are located above kidney

Supplied by suprarenal arteries

Left and right

inferior, superior and middle

Drained differently based on side:

left adrenal vein> renal vein > inferior vena
cava (organs on left have longer course as
they have to cross over to the vena cava
found on the right side of the body.)

right adrenal vein > inferior vena cava




Cortex and medulla:


Medulla:

secretes adrenaline and noradrenaline

sympathetic nervous system control -
sympathetic nervous system activation
releases ACh at synapse, which causes
adrenal medulla to release adrenaline and
noradrenaline

Cortex: produces three different hormones

Mineralocorticoids (aldosterone) —> Zona
glomerulosa G




Adrenals 1

, Made from cholesterol, ACTH activates
enzyme needed in first step

Glucocorticoids (cortisol) —> Zona
fasciculata F

Uses precursors from Zona glomerulosa to
make Glucocorticoids

Androgens (testosterone) —> Zona
reticularis R

Uses precursors from Zona fasciculata to
make androgens

Adrenal cortex

1. Mineralocorticoids (aldosterone)

Affects kidney function, and its release is controlled
by the Renin-angiotensin-aldosterone (RAA)

Increases Na/Water resorption

Promotes K/H excretion



2. Androgens (testosterone and DHEA)

Small contribution to androgen production in males
(due to testes)

produces ~50% of androgens for females

Relevant in congenital adrenal hyperplasia where there
is an over/underproduction —> abnormal sex
development



3. Glucocorticoids (cortisol)

Cortisol is a major glucocorticoid that binds to
intracellular receptors

Exerts affect by activating/supressing gene
transcription

Production is stimulated by ACTH




Adrenals 2