49 Questions
What happens to the free cortisol level when CBG levels rise?
It drops initially
What is the role of bound steroids in the body?
They are inactive and act as a hormone reservoir
Where is cortisol primarily metabolized in the body?
Liver
What makes cortisone an active glucocorticoid?
Its conversion to cortisol before exerting effects
What is the primary function of the aldosterone-secreting mechanism?
Defense of intravascular volume
What effect does standing and constriction of the thoracic inferior vena cava have on intrarenal arterial pressure?
Decreases intrarenal arterial pressure
What is one of the major factors affecting Na+ excretion, apart from variations in aldosterone secretion?
ANP (Atrial Natriuretic Peptide)
What is the effect of glucocorticoids on ACTH secretion?
Inhibit ACTH secretion
What occurs when one rises from the supine to the standing position in terms of aldosterone secretion?
Increases aldosterone secretion
Which organ shows a decrease in the number of eosinophils due to the effects of glucocorticoids?
Spleen
What can happen if patients with adrenal insufficiency receive a glucose infusion without glucocorticoids?
High fever ('glucose fever') followed by collapse and death
What changes in the nervous system are reversed only by glucocorticoids in adrenal insufficiency?
Slower than normal β rhythm in electroencephalographic waves
What happens to most of the cortisone formed in the liver?
It is promptly reduced and conjugated to form tetrahydrocortisone glucuronides.
What is the major adrenal androgen mentioned in the text?
Dehydroepiandrosterone
What is the effect of androgens according to the text?
They promote protein anabolism and growth.
How does aldosterone's half-life compare to cortisol?
Aldosterone has a much shorter half-life than cortisol.
How do norepinephrine and epinephrine affect the secretion of insulin and glucagon?
Increase insulin secretion via α-adrenergic mechanisms and inhibit glucagon secretion via β-adrenergic mechanisms
Which adrenergic receptors mediate the vasoconstriction produced by norepinephrine?
α1-receptors
What is the physiologic function of dopamine in the circulation?
Causes renal vasodilation
How does dopamine exert its positive inotropic effect on the heart?
By acting on β1-adrenergic receptors
What is the enzyme responsible for converting cholesterol to pregnenolone in the mitochondria?
Pregnenolone dehydrogenase
Which protein binds cortisol in the circulation?
Transcortin
What is the primary mineralocorticoid secreted in roughly equal amounts to deoxycorticosterone according to the text?
Aldosterone
Which hormone activates adenylyl cyclase via Gs in adrenocortical cells?
ACTH
How do mineralocorticoids like aldosterone affect Na+ reabsorption?
Cause Na+ retention in extracellular fluid
What is the mechanism of action of aldosterone in promoting sodium reabsorption?
Indirectly increases the synthesis of epithelial sodium channels (ENaCs)
What effect does a drop in resting corticoid levels have on ACTH secretion?
Stimulates ACTH secretion
Where does aldosterone bind to initiate its cellular action?
Cytoplasmic receptor
What is the primary regulatory factor involved in increasing aldosterone secretion from the adrenal gland?
Renin from the kidney via angiotensin II
Which condition selectively affects the output of aldosterone without affecting glucocorticoid secretion?
High potassium intake
What effect does a direct rise in plasma K+ concentration have on the adrenal cortex?
Stimulatory effect
Which factor stimulates the output of aldosterone, glucocorticoids, and sex hormones when first administered?
ACTH
What is the primary effect of aldosterone on Na+ reabsorption?
Increase in reabsorption from urine
How does aldosterone affect the exchange of Na+ for K+ in the renal tubules?
Promotes exchange of Na+ for K+
What is the mechanism by which aldosterone stimulates ENaC activity?
Stimulates ENaC insertion
How does a drop in resting corticoid levels affect ACTH secretion?
Increases ACTH secretion
What happens to urine acidity under the influence of aldosterone?
Increases
How do mineralocorticoids like aldosterone affect ECF volume?
Increase it
Glucocorticoids inhibit ACTH secretion.
True
Adrenal insufficiency is characterized by an inability to excrete a water load.
True
In adrenal insufficiency, glucose infusion without glucocorticoids can lead to high fever and collapse.
True
Glucocorticoids decrease the number of circulating eosinophils.
True
Glucocorticoids increase the number of basophils in circulation.
False
Adrenal insufficiency results in the possibility of water intoxication.
True
The appearance of slower electroencephalographic waves in adrenal insufficiency is reversed only by mineralocorticoids.
False
Neutrophils' numbers decrease due to the effects of glucocorticoids.
False
Personality changes in adrenal insufficiency include irritability and inability to concentrate.
True
Glucocorticoids increase ketone body formation in diabetics.
True
Test your knowledge on the effects of adrenal gland hormones on plasma glucose, lipid levels, ketone body formation, ACTH secretion, and the nervous system. Explore negative feedback responses and physiological changes related to adrenal insufficiency.
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