Endocrine Histology II - Wright Flashcards
Blood supply to and from suprarenal glands
From Renal Artery
Directly from aorta
From inferior phrenic artery
Venous drainage via one suprarenal vein
3 Zones of cortex for suprarenal glands
Capsule
Cortex:
From outer to inner:
Zona Glomerulosa
Zona Fasciculata
Zona Reticularis
Medulla
Cortical cells secrete 3 classes of hormones, all derived from ____:
cholesterol:
Mineralocorticoids - aldosterone (sodium in blood) Salt
Glucocorticoids - cortisol (influence glucose metabolism) Sugar
Androgens - dehydroepiandrosterone (DHEA) Sex
(helps regulate male characteristics)
Zona Glomerulosa: Secrete ______ in response to increased ____
Secrete mineralocorticoids (aldosterone) as part of renin-angiotensin system, in response to increased K+ levels or decreased blood flow to kidneys.
Cells ovoid in shape / clusters or arches
Aldosterone regulates body’s concentration of electrolytes, primarily ___ and ___, by acting on the _________ and _______ of kidney nephrons to: a. b. c.
sodium / potassium
acting on distal convoluted tubule and collecting ducts
a. increase sodium reabsorption
b. increase potassium excretion
c. increase water reabsorption through osmosis
Zona Fasciculata chiefly produces:
Glucocorticoids (mainly cortisol) - regulates metabolism of glucose, especially in times of stress
Small amounts of weak androgens (dehydroepiandrosterone)
Cells organized in bundles (fascicles)
Zona reticularis
cells produce 3 important sex hormones
Cells arranged in cords (net-like appearance, look like reticulum)
Cells in reticularis produce precursor sex hormones including dehydroepiandrosterone (DHEA), DHEA sulfate and androstenedione from cholesterol. Just memorize that they produce ANDROGENS
Adrenal medulla: mainly composed of _____
Conversion of which AAs to which catecholamines?
What happens during stress/imminent danger/exercise?
Mainly composed of hormone-producing Chromaffin cells
Conversion of Tyrosine into catecholamines: Epinephrine, norepinephrine, and dopamine
Response to stress: Medullary cells release catecholamines into blood in 17:3 ratio of epinephrine to norepinephrine.
Extra: Only place in body where cells are innervated by preganglion and not postganglion.
Thyroid gland location
formed of two lobes connected by a ___
Located in anterior neck just inferior to the larynx
Isthmus
Some people have this in their thyroid gland, which is a remnant of what?
Pyramidal lobe, which is a remnant of thyroglossal duct
What divides the lobules in the thyroid gland?
Septa from the capsule divide the gland into lobules. These provide a conduit for blood vessels, lymphatics, and nerves
Function of the colloid:
Storage site for T4, T3 bound to thyroglobulin (TG).
Role of follicular cells:
Synthesis of Thyroglobulin and thyroid hormones.
Extra: these are also called principAL cells
What causes a goiter?
Not enough iodine. No iodine = no formation of T3, T4, thus TSH accumulates.
Role of C cells (parafollicular cells)
Role of C cells: release calcitonin which decrease serum calcium levels in 3 ways:
Inhibits osteoclast activity in bones
Inhibit Ca2+ absorption by intestines
Inhibit Ca2+ and phosphate reabsorption by kidney tubules
