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
Location of parathyroid glands:
2 on right , 2 on left, all posterior to thyroid
2 cell types of parathyroid glands:
Chief (principal) cells: secrete parathyroid hormone which increases blood calcium
stimulates osteoclasts to release calcium
increases gastrointestinal calcium absorption by activating vitamin D, promotes calcium uptake by kidneys
Note: Does complete opposite of calcitonin.
Oxyphil cells: we don’t know what they do
Pineal (pine-cone like)
Formed of what and what is it surrounded by?
Formed of pinealocytes and interstitial cells
Surrounded by pia mater
Pinealocytes
contain secretory vesicles, many mitochondria
synthesize and release melatonin
Brain sand
corpora arenacea
concretions of calcium phosphates and carbonates
in pineal.
Superior cervical ganglion:
Pineal is innervated by post-ganglionic sympathetic fibers from this.
It is a big sympathetic ganglion at base of your skull
