A&P2 Quiz 3

How would an increase in [Na+] in extracellular fluid affect aldosterone secretion?

*very slight* decrease in aldosterone secretion.

Aldosterone-mediated increase in blood volume that lasts more than ______ days leads to a rise in _______ pressure, which causes pressure ______ and _____ by the kidneys.

1-2 days; arterial; natriuresis; diuresis.

What are the three ways aldosterone secretion is regulated?

1. [K+] in extracellular fluid 2. increased activity of renin-angiotensin system 3. [Na+] in extracellular fluid

What are the three treatments of Conn's syndrome? Hint: two treatments are pharmacologic.

1. surgical removal of the adrenal tumor 2. treatment with spironolactone (blocks the mineralocorticoid receptor to prevent aldosterone from binding). 3. treatment with amiloride (blocks ENaC to prevent Na+ reabsorption).

About _______ mg/day of cortisol is secreted by the adrenal cortex.

15-20

The human body has _______ adrenal glands that have _______ distinctive parts

2; 2

Approximately ______% of aldosterone is plasma protein bound.

60

What is the synthetic mineralocorticoid that is slightly more potent than aldosterone?

9-alpha-fluorocortisol

Approximately _______% of cortisol is plasma protein bound.

90-95%

When POMC is cleaved, _______ and _______ are produced.

ACTH and MSH.

What would be the clinical symptoms and outcome of a person whose body has lost all ability to either secrete or respond to aldosterone?

Absolutely no sodium reabsorption is possible and they'd present with severe dehydration and hypotension. This would lead to circulatory shock and death within about 3 days.

A person with low aldosterone, low cortisol, and elevated ACTH along with blotchy skin pigmentation is characteristic of ________.

Addison's disease.

______ disease is a type of hypoadrenalism.

Addison's.

What is secreted by the zona reticularis?

Adrenal androgens, such as DHEA and sex hormones.

How is blood pH affected by aldosterone secretion? Explain.

Aldosterone secretion will cause reabsorption of Na+ to the blood in exchange for potassium. Therefore [K+] in the blood will decrease *and sometimes* [H+] will also decrease. As a result, the blood will be mildly alkaline.

What is the *acute life-saving* portion of the adrenocortical hormones?

Aldosterone!

If cortisol causes fat catabolism, how does excessive cortisol release lead to obesity?

Although excessive cortisol causes mobilization/catabolism of fats, it also causes insulin secretion and resistance. Insulin is a fat sparer: it takes fatty acids and deposits them in tissues throughout the body.

Cortisol has anti-inflammatory effects. Explain why this happens.

Cortisol causes production of lipocortins, which an inhibitory protein of phospholipase. This prevents the release of arachidonic acid from membrane phospholipids and therefore inhibits synthesis of prostaglandins and leukotrienes.

How can excessive and prolonged cortisol release induce T2DM?

Cortisol increases gluconeogenesis, decreases glucose utilization by cells which leads to hyperglycemia. This stimulates insulin release, but cortisol has induced decreased sensitivity to insulin. Eventually, beta cells get exhausted, leading to a type 2 diabetes mellitus-like condition.

What is the primary function of cortisol?

Cortisol is needed to resist physical and mental stress.

_______ is very potent and accounts for 95% of total glucocorticoid activity.

Cortisol.

What synthetic glucocorticoid is *almost* as potent as cortisol?

Cortisone

"moon-face," "buffalo-hump," and truncal obesity are all characteristic of _______ disease.

Cushing's

In what metabolic disorder is there excessive cortisol secretion that causes fat deposition in the neck, head, and abdominal region?

Cushing's disease.

Purple striae are seen in what adrenal disease?

Cushing's syndrome.

_______ is a type of hyperadrenalism.

Cushing's syndrome.

Ketoconazole can be used to treat _______ (adrenal disease) by blocking ______.

Cushing's syndrome; steroidogenesis.

What synthetic glucocorticoid is *30 times as potent* as cortisol and exhibits *intense* glucocorticoid activity?

Dexamethasone.

How would elevated aldosterone affect stool formation?

Elevated aldosterone leads to constipation

Where is the renal tubule Na+/K+ ATPase found and what is its function?

Found on the renal interstitial fluid (blood side) face of the renal tubule epithelial cells. It takes sodium from the renal tubule cell and moves it into the blood in exchange for potassium. (so Na+ moves from cell to blood and K+ moves from blood to cell)

What disease is associated with thyroid-stimulating immunoglobulin?

Grave's disease.

A patient presents with somnolence, bradycardia, depression, and cold intolerance. He also has hyperlipidemia, high TSH, and presence of thyroid peroxidase antibody and thyroglobulin antibody. What is your diagnosis and how would you treat it?

Hashimoto's hypothyroidism. Treat with levothyroxine.

In what disease state are spironolactone and amiloride used? Explain.

Hypertension. Both drugs cause decreased reabsorption of Na+ from urine to the blood. This leads to decreased blood volume and a lower blood pressure.

Describe the hypothalamic-pituitary-adrenal axis that results in the release of cortisol.

Hypoglycemia stimulates corticotropin releasing hormone to be released by the hypothalamus and travels to the anterior pituitary where it stimulates the AP to release corticotropin. Corticotropin acts on the zona fasciculata of the adrenal cortex and this causes cortisol secretion.

What is the physiological role of glucocorticoids?

Increase blood glucose levels and affect protein and fat metabolism.

How is blood volume affected by aldosterone secretion? Explain.

Increased. This is because aldosterone causes Na+ reabsorption in the blood. Where Na+ goes, water follows. Therefore, blood volume will increase.

All people with high levels of aldosterone do not have Conn's syndrome. What else should we look at to determine if elevated aldosterone could be due to Conn's syndrome?

Levels of renin. Normally, high levels of renin would mean high levels of aldosterone. However, a person with Conn's syndrome has high levels of aldosterone and low levels of renin.

A big decrease in aldosterone secretion (abnormally low) would have what effects on the heart and why?

Low aldosterone causes increase in blood [K+] which leads to arrhythmia, afib, and tachyarrhythias.

How would increased release of adrenocorticotropic hormone (ACTH) affect aldosterone secretion?

NO EFFECT! Remember: aldosterone secretion is NOT regulated by ACTH.

What are the two proteins that are synthesized as a result of aldosterone secretion?

Na+/K+-ATPase pump and the epithelial sodium channel (ENaC).

What ion would one expect to find in abundance in the sweat of a person who just stepped outside on a very hot day? What ion would be most prevalent in the sweat of the same person that has been exposed to high temps for prolonged period? Answer choices: K+ and Na+

Na+; K+

What is Addison's disease?

Primary atrophy of the adrenal cortex due to an autoimmune response or cancer.

What is Conn's syndrome and what is its effect on plasma K+, Na+, H+, and blood pressure?

Small tumor of the zona glomerulosa cells which cause them to secrete large amounts of aldosterone. Causes: decreased plasma K+ increased plasma Na+ decreased H+ increased blood volume increased blood pressure

Someone with a deiodinase deficiency would be expected to have really low levels of ______ hormone.

T3.

What happens when Aldosterone binds to its receptor?

The aldosterone-receptor complex diffuses into the nucleus which leads to transcription and translation of genes related to Na+/K+ transport.

Describe the aldosterone escape.

The process by which kidneys respond to prolonged elevation of aldosterone. This happens when BP is approaching threshold. The kidneys must attempt to restore normal (or safe) BP though excretion of water and sodium even in the presence of aldosterone.

What would explain the muscle weakness and paralysis in a person who has a tumor in the zona glomerulus of their adrenal cortex?

This causes increased levels of aldosterone secretion, which causes hypokalemia. Hypokalemia leads to muscle weakness/paralysis.

What happens when aldosterone binds to receptors on sweat glands?

This causes reabsorption of sodium (and as a result, water) and replace it with potassium. This helps to conserve water and sodium in really hot climates.

What zone of the adrenal cortex secretes the glucocorticoids? Give the two primary glucocorticoids secreted by this zone.

Zona fasciculata. Secretes cortisol and corticosterone

The adrenal cortex is divided into three distinct zones. Give the name of each zone and identify the outermost and the innermost.

Zona reticularis (innermost nearest to adrenal medulla) Zona fasciculata Zona glomerulosa (outermost)

How would a tumor in the zona glomerulosa of the adrenal cortex affect the following: blood [Na+] blood volume blood pressure blood [K+] blood pH

[Na+] in the blood increases, which causes increase in blood volume and blood pressure. [K+] in the blood decreases blood pH would increase (becomes more alkaline).

Mineralocorticoids, such as ________, are secreted by the zona glomerulosa.

aldosterone

The mineralocorticoid _______ is very potent and accounts for 90% of all mineralocorticoid activity.

aldosterone

What adrenocortical hormone participates in the renin-angiotensin system?

aldosterone

Someone with Conn's syndrome would be expected to have mild metabolic _______ (acidosis/alkalosis).

alkalosis.

Acne and excessive growth of facial hair (hirsutism) is caused by elevated _______ seen in ________ (Addison's Disease/Cushing's Syndrome) due to tumor in the_____.

androgens; cushing's syndrome; anterior pituitary

Cushing's syndrome caused by a tumor in the _______ will also show elevated levels of androgens.

anterior pituitary.

If a person with Cushing's syndrome has blotchy skin pigmentation, they likely have a tumor of the ________.

anterior pituitary.

What is the MOA of amiloride?

blocks the ENaC protein on the epthelial cells of renal tubule.

What second messenger system is activated by corticotropin?

cAMP

Cortisol causes ______ of fats.

catabolism.

Cortisol causes protein _____.

catabolism.

What effect does cortisol have on blood glucose?

causes elevated blood glucose.

Adrenocortical hormones are derived from _______.

cholesterol

Aldosterone _______ sodium at the expense of _______, sometimes _______.

conserves; potassium; hydrogen.

What is the outer part of the adrenal gland called and what does it secrete?

cortex; corticosteroids (adrenocortical hormones)

What glucocorticoid accounts for about 4% of total glucocorticoid activity?

corticosterone

Stress excites the hypothalamus, which causes an increased secretion of _______ and this stimulates the anterior pituitary to increase secretion of ______.

corticotropic releasing hormone; adrenocorticotropic hormone.

The major endogenous glucocorticoid is _____.

cortisol.

Which adrenocortical hormone shows higher rate of protein binding: Aldosterone or cortisol?

cortisol.

The principal glucocorticoid is _______ and it is important in resisting ______.

cortisol; physical and neurogenic stress.

What will the body weight, BMR, and appetite be like in someone with hypothyroidism?

decreased BMR, increased body weight, and decreased appetite.

Aldosterone levels are ______ in Addison's disease.

decreased.

Someone with Addison's disease will have _____ renal Na+ reabsorption.

decreased.

Cortisol ________ (increases/decreases) glucose utilization by cells by _______ (increasing/decreasing) sensitivity to insulin.

decreases; decreasing.

Which glucocorticoid would be ideal for administration to hypertensive patients?

dexamethasone (because it has no mineralocorticoid effect).

What are the gastrointestinal effects of Addison's disease?

diarrhea

Thyroid hormones cause vaso______ (constriction/dilation).

dilation

What will the levels of cortisol and ACTH be like in someone with Cushing's syndrome due to a tumor of the adrenal cortex?

elevated cortisol; low levels of ACTH.

What is the most important regulator of aldosterone secretion?

extracellular [K+].

What is the secretion of mineralocorticoids from the zona glomerulosa controlled by?

extracellular fluid of potassium.

True or false: Similar to its endogenous counterpart, dexamethasone exhibits very slight mineralocorticoid activity in addition to its primary role as a glucocorticoid.

false!! Shows no mineralocorticoid activity.

The secretions of the zona ______ and zona ______ are regulated by adrenocorticotropic hormone (ACTH).

fasciculata; reticularis.

How would an increase in [K+] in the extracellular fluid affect aldosterone secretion?

greatly increases aldosterone secretion.

Low cortisol or high cortisol? Cushing's syndrome.

high

The triglycerides and cholesterol levels in someone with hypothyroidism will be _____.

high

What will the levels of cortisol and ACTH be like in someone with Cushing's syndrome due to a tumor of the anterior pituitary?

high cortisol; high ACTH.

High POMC means you'll have _______ ACTH and ________ MSH. This can be observed by the ________ of skin.

high; high; blotchy pigmentation

Someone with Conn's syndrome is expected to have _______ (low/high) concentration of plasma aldosterone and ________ (low/high) concentration of plasma renin.

high; low

In addition to stress response, cortisol also plays a role in preventing _______ during periods of _____.

hypoglycemia; fasting.

Someone with Addison's disease will have trouble with blood glucose regulation. What is the result of this?

hypoglycemia; they will have lack of energy and muscle weakness.

Thyroid hormones _______ active transport of ions through cell membranes.

increase (this is done through increasing the # of Na/K ATPase transporters in cells)

How would *decreased* [Na+] in extracellular fluid affect aldosterone secretion?

increase aldosterone secretion.

What effect do thyroid hormones have on mitochondria?

increase the number and activity of mitochondria in cells.

What will the body weight, BMR, and appetite be in someone with hyperthyroidism?

increased BMR, decreased body weight, increased appetite.

Cushing's syndrome is associated with excess secretion of cortisol. What are the slight mineralocorticoid effects of cortisol?

increased BP, hypokalemia, and milk alkalosis.

What would one expect to be the result of a tumor in the zona reticularis?

increased levels of androgens.

What will the pulmonary respirations be like in someone with hyperthyroidism?

increased rate and depth

Someone taking amiloride would be expected to have ________ (increased/decreased) [Na+] in urine as compared to a person not on amiloride.

increased.

Someone who is taking spironolactone would be expected to have _____ (increased/decreased) plasma [K+].

increased.

What is the result of thyroid hormones on BMR?

increases BMR of every cell in the body.

What effects do thyroid hormones have on appetite and body weight?

increases appetite and food intake and decreases body weight.

How would increased activity of the renin-angiotensin system affect aldosterone secretion?

increases levels of angiotensin-2 which increases aldosterone secretion

Adrenocortical hormones are metabolized in the ______ and excreted mainly by the ______.

liver; kidneys.

The half-life of cortisol is ______ than that of aldosterone.

longer.

Low cortisol or high cortisol? Addison's disease

low

The triglycerides and cholesterol levels in someone with hyperthyroidism are _______.

low

_______ levels of aldosterone lead to diarrhea.

low

What is the physiologic role of mineralocorticoids?

maintain electrolyte balance in the extracellular fluids of the body.

What is the inner part of the adrenal gland called and what is secreted by this part of the adrenal gland?

medulla; NE and epinephrine

What is MSH?

melanocyte stimulating hormone.

How does hypothyroidism affect *women*?

menorrhagia, polymenorrhea, amenorrhea, and greatly decreased libido

What can one use to treat Grave's disease?

methimazole or propylthiouracil.

What synthetic glucocorticoid is five times as potent as cortisol?

methylprednisone

What is Spironolactone and what is its MOA?

mineralocorticoid antagonist. Blocks the mineralcorticoid receptor so that aldosterone cannot bind.

Aldosterone binds to _______ receptors located in the ________.

mineralocorticoid; cytoplasm.

What are the three types of adrenocortical hormones secreted by the adrenal gland?

mineralocorticoids glucocorticoids androgenic hormones

Levels of cortisol are highest during ______ and decline during _____.

morning (upon rising and getting ready for the day); afternoon.

Thyroid hormones bind to receptors in the ______.

nucleus.

Hyperthyroid women may experience ________, and occasionally _______.

oligomenorrhea; amenorrhea.

Where is the ENaC protein located? What is the function of ENaC?

on the lumen side (urine side) of the renal tubule. ENaC sequesters Na+ from the urine and moves it back into the renal tubule epithelial cell.

What is POMC?

precursor to ACTH.

What synthetic glucocorticoid is four times as potent as cortisol?

prednisone.

________ hypothyroidism is due to faulty thyroid gland.

primary

Conn's syndrome is also known as ________.

primary aldosteronism.

A patient with heat intolerance, increased sweating, exophthalmos, tachycardia, and low TSH as well as presence of thyroid stimulating immunoglobulin likely has ________.

primary hyperthyroidism due to Grave's disease.

What are the two antithyroid substances from class?

propylthiouracil and methimazole.

Initially during a stress response, cortisol helps to mobilize _____ and ______ and elevates _____ for quick energy. What does cortisol due after the initial stressor has subsided and epinephrine release has also subsided?

proteins; fats; blood glucose; later on, cortisol acts to increase appetite.

Aldosterone acts on __________ cells to cause increased sodium _______.

renal tubular epithelial; reabsorption.

______ hypothyroidism is due to tumor in anterior pituitary.

secondary

Transport of _______ is the easiest way to generate any type of secretion for cells. Explain this.

transport of Na+ out of cell. This is because water follows sodium.

True or false: Corticosterone has slight mineralocorticoid activity.

true

True or false: No blotchy skin pigmentation is seen in Cushing's syndrome that is caused by tumor of the adrenal cortex.

true

True or false: Aldosterone acts to conserve sodium in the body by preventing loss from sweating, salivation, stools, and urine.

true!

True or false: Excessively high levels of aldosterone can lead to increased urination and Na+ excretion by the kidneys.

true! This happens when aldosterone is in such excess that one becomes hypertensive up to critical threshold. When this happens, the kidneys are forced to get rid of water (and sodium) even though aldosterone is still present. This is an attempt by the body to keep blood pressure below critical threshold.

True or false: ACTH has no role in the regulation or secretion of aldosterone.

true!!

True or false: Immunosuppression and osteoporosis may be seen in Cushing's syndrome.

true.

True or false: If the zona glomerulus of the adrenal cortex is not functioning or is absent, the patient will die.

true. This is the acute life-saving portion of the adrenal cortex. No glomerulus = death.

True or false: Cortisol has some mineralocorticoid activity in addition to glucocorticoid activity.

true; but its mineralocorticoid activity is very slight.

What is pressure natriuresis?

when rise in arterial pressure causes increased excretion of sodium.

Cortisol is secreted from the ______ of the adrenal cortex.

zona fasciculata

Aldosterone is secreted from the ______ of the adrenal cortex.

zona glomerulosa.

What zone of the adrenal cortex secretes androgens?

zona reticularis.