Endocrine - Adrenal Flashcards
What is the parenchyma of the adrenal gland divided into?
Cortex - outer - yellowish
Medulla - inner - reddish-brown
Where do cortical cells of the adrenal gland originate from? Medullary cells?
Mesenchyme - cortical cells (mesodermal)
Neural crest cells - Medullary cells (ectodermal)
How is the adrenal gland organized?
Endocrine gland - cords of secretory cells arranged along fenestrated capillaries
What is the capsule of the adrenal medulla formed by? What does it send into the parenchyma of the gland?
Dense CT
Sends trabeculae into the gland
What percent of the adrenal gland does the cortex form?
90%
As the steroid producing part of the gland, what three things does the cortex produce?
Mineralcorticoids
Glucocorticoids
Androgens
What organelle is abundant in the cells of the cortex?
SER
Are steroids stored int he cytoplasm of cortical cells or released immediately?
Released immediately
What are the three zones of the adrenal cortex? Percent of the cortex?
Zona glomerulosa - 15%
Zona fasciculata - 65%
Zona reticularis - 7%
What type of cells are in the zona glomeruloas? How are they arranged?
Cuboidal/pyramidal cells
Arch cords or curved columns
What do cells of the zona glomerulosa secrete? What does this ultimately do?
Mineralocorticoids - regulate Na and K homeostasis and H2O balance
What is the principal mineralocorticoid secreted by the zona glomerulosa?
Aldosterone
What 4 tissues does aldosterone act on to cause reabsorption of Na?
Kidney tubules
Gastric mucosa
Salivary glands
Sweat glands
What system provides feedback to the zona glomerulosa? What specifically?
Renin-angiotensin-aldosterone system
Angiotensin II stimualtes zona glomerulosa to produce aldosterone
What cells are found in the zona fasiculata? How are they typically arranged?
SPongiocytes
One or two cell thick straight cords
What do spongiocytes mainly secrete?
Glucocorticoids (such as cortisol)
What are two important role of glucocorticoids?
Increasing metabolism of glucose and FA
Depressing immune and inflammatory responses - decreasing IL-1 and IL-1 from lymphocytes and macrophages and decreasing lymphblast mitosis within lymph nodes
What controls glucocorticoid production?
ACTH produced by corticotropes of anterior pituitary
Besides signaling glucocorticoid production, what else is ACTH also necessary for in the adrenal gland?
Increase growth and blood flow through gland
What is the inner most layer of the adrenal cortex? What do these small cells contain? How do they stain?
Zona reticularis
Lipofuscin granules
Eosin (intense, due to fewer lipid droplets)
What two things do cells in the zona reticularis secrete?
Androgens and glucocorticoids
What are the two types of cells found in the adrenal medulla?
Chromaddin cells
Ganglion Cells
What are chromaffin cells derived from? Theya re modifed what?
Neural crest cells
Modified postsynaptic neurons
What suppresses axonal growth of chromaffin cells?
Glucocorticoids
What do cromaffin cells store and secrete?
NE and Epi
How do chromaffin cells secreting NE differ from those secreting Epi?
NE - larger secretory granules - 20%
Epi - smaller secretory granules - 80%
What innervates chromaffin cells?
Sympathetic nerve fibers
What is released fom the synaptic terminals of sympathetic nerve fibers to cause degranulation of chromaffin cells?
Acetylcholine
What do ganglion cells of the adrenal medulla do?
Modulate activity of chromaffin cells
What supplies the adrenal gland with blood?
Suprarenal arteries
How is the blood supply organized in the adrenal medulla?
Capsular arteries - irrigate capsule
Cortical arteries - form fenetrated cortical sinusoidal cap
Medulalry arteries - pass through cortex and supply medulla
What are the two blood supplies of the adrenal medulla? What do each contain?
Medullary arteries - oxygenated blood
Cortical capillaries - glucocorticoid rich blood
What structures collect the blood from within the medulla? What do these then drain into?
Adrenomedullary collecting veins
Large central adrenomedullary vein
to IVC on rights and left renal on left
