Question

Anatomy Tutorial: The Adrenal Glands

Answer 1

\({\bf{Overview:}}\)



> at the superior poles of kidneys, attached by fibrous capsule
> project into the peritoneal cavity, covered by peritoneum
> vascular; supplied by renal artery, phrenic artery, aorta, drained by adrenal veins
> adrenal cortex: secretes steroids
> adrenal medulla: secretes catecholamines

\({\bf{Adrenal~Cortex:}}\)
> makes corticosteroids
> smooth ER for synthesis of lipid-based steroids

three layers, going from outer to inner:
> zona glomerulosa: produces mineralocorticoids
> zona fasciculata: produces glucocorticoids
> zona reticularis: secretes androgens

Answer 2

\({\bf{Zona~Glomerulosa:}}\)
> densely packed endocrine cells
> 15% of the entire adrenal cortex
> produce mineralocoticoids: steroids that change elecrolyte composition
- aldosterone: retains sodium ions and eliminate potassium ions
- spurred by decreasing sodium levels in blood, increasing potassium levels, and angiotensin II

\({\bf{Zona~Fasciculata:}}\)
> 80% of the cortex
> larger cells, more lipid-based
> sinusoids w/ fenestrations
> spurred by ACTH production from pituitary gland
> produces glucocorticoids: steroids that change glucose metabolism
- cortisol
- corticosterone
which increase glucose + glycogen production

\({\bf{Zona~Reticularis:}}\)
> 5% of the cortex
> folded network supplied by capillaries
> makes androgens, steroids that increase muscle mass, blood cell production, and pubic hair esp. in women (since men already have androgens supplied by testes)

Answer 3

\({\bf{Adrenal~Medulla:}}\)
> innervated by SNS
> cells are called chromaffin cells
> vascular
> secretes catecholamines
- epinephrine (adrenaline): higher amounts than norepinephrine; increase cellular metabolism, muscle strength, endurance
- norepinephrine: similar effect to andrenaline
> longer lasting than other effects by the SNS

Answer 4

Adapted from Human Anatomy, Martini, et. al. 9th edition