Adrenal Glands- Driscoll Flashcards
What contribute to maintaining homeostasis through salt/ water/ potassium balance, stress responses, and control of BP?
Adrenal Gland
What are the 2 families of hormones that adrenal gland produces and which family is the chief secretory product?
steroid hormones (Chief product) catecholamines
What are secreted by the adrenal gland and correspond to the steroid hormone category?
glucocorticoids, mineralcorticoids, and androgens
What are secreted by the adrenal gland and correspond to the catecholamine category?
norepinephrine and epinephrine
Where are the majority of hormones produced in the adrenal glands?
the cortex (90%)
What are the four functional zones of the adrenal gland?
the Zona glomerulus
The zona fasciculata
The zona reticularis
Medulaa
Do we really need our adrenal glands?
yes, if you dont have one you will die within 2 weeks and go into hypovolemic shock (i.e you dot have any blood volume) or hypoglycemic coma (cuz cortisol can help you out to increase glucose)
What does the zona glomerulosa produce and what effects the rate of secretion?
Aldosterone (mineralcorticoids)
ECF volume and the kidneys (via Renin angiotensin system)
What does the zona fasciculata produce and what effects the rate of secretion?
Coritsol (glucocorticoids)
cortisol is a glucocorticoid because it affects the rate of glucose secretion*
ACTH effects the release of cortisol
What is a mineralcorticoid?
Affects the electrolytes (minerals) of the body
What is a glucorticoid?
affects the level of glucose in the body ( and protein and fat metabolism)
What are androgens?
sex hormones
What does the zona reticularis secrete and what controls this rate of secretion?
androgens and DHEA
ACTH
What does the medulla secrete and what controls this rate of secretion?
catecholamines (norepi and epi (majority))
Sympathetic nervous system
What is DHEA?
a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids
Cortisol is special because it has a dual property, i.e it is a glucocorticoid as well as a (blank)
mineralcorticoid
What is the most potent mineralocorticoid?
Glucocorticoid?
aldosterone
cortisol
What are these? Deoxycorticosterone corticosterone flurocortisol**** cortisol cortisome
Mineralcorticoids
flurocortisol is more potent than aldosterone*
What are these and put them in order of potency?
glucocorticoids
dexamethasone>methylprednisone>prednisone>cortisol>cortisone>corticosterone
How are adrenocortical hormones transported throuh the blood?
free and bound to albumin or CBG
Is most cortisol bound or free?
Aldosterone?
95% is bound
60% is bound
If a hormone is bound to a protein does it have a longer or shorter half life? Considering that more cortisol is bound then aldosterone what can you expect the half life of cortisol to be, longer or shorter than aldosterone?
longer half life
longer than aldosterone
Which is found in larger concentrations in the blood, aldosterone or cortisol?
cortisol (and it is secreted in much higher quantities than aldosterone)
Where are plasma binding proteins for adrencorticol hormones produced?
in the liver
Where does inactivation of hormones occur?
liver
Where are conjugates excreted?
in the urine
What does aldosterone do?
increases Na absorption and K excretion (i.e. increaeses EFV)
What does aldosterone target in the kidney?
principle cells of distal tubule and intercalated cells of collecting duct
What does other places does aldosterone target other than the kidney?
sweat glands
salivary glands
intestinal epithelial cells
(all about conservation of salt)
Are steroid hormones lipid soluble, what does this mean for them?
yes, than can diffuse through cell membrane
Explain the cellular mechanism of aldosterone action
Aldosterone is a steroid so it diffuses into the cell and meets up with a cytoplasmic mineralcorticoid receptor, the complex then enters the nucleus and promotes gene transcription of proteins that aid in Na transport
What does aldosterone promote the gene transcription of?
Enzymes (Na/K atpase)
membrane transport proteins (Na Channels)
(blank) cause a change in gene transcription so these effects take a while to see (about an hour)
mineralcorticoids
Aldosterone has two major effects what are they?
Regulates blood pressure through:
genomic effects-> create proteins to aid in Na transport
Non-genomic effects-> second messanger cascade with H,HCO3 transport
Which effect of aldosterone is faster, the non genomic or genomic effects?
non genomic are faster
Explain how aldosterone works as a nongenomic effector?
aldosterone binds to receptor which causes increase in PK which phosphorylates things and activates target proteins to allow for H secretion and HCO3 absorption
What happens if you dont have aldosterone?
you get hyponatremic
What has the opposite effect of aldosterone?
ANP released from cardiac cells
When you have a lot of aldosterone does your sodium plasma CONCENTRATION increase a lot?
no it doesnt because as more salt is absorbed, more water is so there is still the same ratio of salt to water
Aldosterone secretion leads to increased sodium and fluid retention which leads to increased blood volume which leads to increased (blank) which leads to elevation of blood pressure
cardiac output
If you have increased levels of aldosterone you will eventually have increased levels of ECF which, if lasting more than 2 days can result in what?
increased arterial pressur
When you have increased arterial pressure, how does your body lower this pressure?
Distal tubule in kidney starts excreting sodium and water
this is called aldosterone escape
If you have too much aldosterone you can get hypokalemia, where did all your potassium go?
What can this cause?
moved into urine and into cells
muscle cramping and weakness
If you have too little aldosterone you can get hyperkalemic which can cause what?
severe cardiac toxicity (arrhythmias and weak heart contractions)
Aldosterone causes potassium to be secreted into the tubules in exchange for sodium reabsorption in the (blank)
principle cells
Aldosterone causes secretion of hydrogen ions for sodium in the (blank)
intercalated cells
Since cortisol is not very potent as a mineralcorticoid how come it still has a pretty good effect on the body?
because it is in such high concentration in the body and has really high affinity for mineralcorticoid receptors
Renal epithelial cells can converts cortisol to cortisone via what enzyme?
Why would you want cortisone?
11B hydoxysteroid dehydrogenase type 2
cuz cortisone wont bind to mineralcorticoid receptors so you wont have mineralcorticoid effects
What does IIb-HSD1 do?
converts cortisone to cortisol to be used as a mineralcorticoid
What is psuedohyperaldosteronism (apparent mineralocorticoid excess syndrome (AME)?
it is when you are exhibiting symptoms of having too much aldosterone but really you just have too much cortisol (acting like a mineralcorticoid) due to a defect in cortisol converting to cortisone via 11BHD2 (can occur via a mutation or eating too much licorice)
Why would licorice lead to AME (pseudohyperaldosteronism)?
How can you tell you have pseduo and not real?
it makes glycyrrhetinic acid which blocks 11BHD2
in pseudo you will have low aldosterone levels
What is aldosterone secretion regulated by?
potassium and angiotensin levels in the ECF, YES it is totally surprising that Na Levels have almost no effect on aldosterone. ACTH levels just tell the adrenal glands that they can secrete aldosterone but they dont really regulate aldosterone levels.