Adrenal Gland Flashcards
(30 cards)
Which is the steroid secreting portion of the Adrenal gland?
the cortex
Which is the catecholamine secreting portion of the adrenal gland?
the medulla
Where do the cells of the cortex originate from embryologically?
mesodermal mesenchyme
Where do the cells of the medulla originate from embryologically?
neural crest
What is the function of the parenchymal cells of the adrenal cortex?
regulate metabolism, maintaining normal electrolyte balance
Where do the corticol and medullary sinusoids drain into?
adrenomedullary collecting veins—> central adrenomedullary veins –> left renal or IVC (right side)
What is unique about the central adrenomedullary vein?
It has a tunica media with longitudinal smooth muscle bundles
Chromaffin cells are considered postsynaptic neurons but why do they lack axonal processes?
axonal growth is inhibited by glucocorticoids, a hormone secreted by the adrenal cortex
Mineralocorticoids are produced where? what is its functino?
Parenchymal cells of the zona glomerulosa in the adrenal cortex – control electrolyte homeostasis (@ distal tubule of kidney to increase sodium reabsorptionand decrease potassium reabsorption) maintain osmotic balance in urine and prevent serum acidosis (EX. ALDOSTERONE)
Glucocorticoids are produced where? what is its function?
parenchymal cells of zona fasciculata in adrenal cortex– promote normal metabolism (increase rate of aa transport, promote removal of protein from skeletal muscles and its transport to liver, supress inflammatory response and some allergic reactions
Gonadocorticoids are produced where? what is its function?
parenchymal cells of the zona reticularis in the adrenal cortex– induce weak masculinizing effect
norepinephrine and epinephrine is produced where? what are their functions?
chromaffin cells of the andrenal medulla– similar to sympathetic effects
What are the two different chromaffin cell populations? what do they secrete?
- dense core vesicle: norepinephrine
2. contains vesicles (smaller): epinephrine
What are chromogranins?
They are soluble proteins that help bind catecholamines and are exocytosed with the hormones
What is the effect of the drug, reserpine?
causes depletion of catecholamines form vesicles by inhibiting its magnesium activated ATPase transport mechanisms
What hormone induces methylation of norepinephrine to epinephrine?
glucocorticoids
What are the three zones of the adrenal cortex?
zona glomerulosa (outermost), zona fasciculata, zona reticularis (innermost)
What are pheochromocytomas?
Tumors derived from chromaffin cells –> cause excessive catecholamine secretion.
What are effects of alpha-adrenergic receptor stimulation?
elevated blood pressure, increased cardiac contractility, glycogenesis, gluconeogensis, and intestinal relaxation
Stimulation of beta- adrenergic receptors results in what?
increase in heart rate and contractility
What is the function of aldosterone?
blood pressure, sodium levels and blood volume increase
What is the system that provides feedback control of the zona glomerulosa?
renin-angiotensin-aldosterone system
Describe the conversion of angiotension –> angiotensin II
Renin: Angiotensin –> angiotensin I
ACE: angiotensin I –> Angiotensin II
(angiotensin II stimulates aldosterone)
Describe the function of glucocorticoids in:
liver, adipose tissue, other tissue, cells
liver: stimulate conversion of amino acids to glucose, polymerization of glucose to glycogen, promote uptake of AA and fatty acids
adipose tissue: breakdown of lipids to glycerol, and free fatty acids
other tissue: reduce rate of glucose use and promote oxidation of fatty acids
cells: inhibit protein synthesis to provide amino acids for conversion to glucose in liver
