7/21 Quiz

What is the rate-limiting step in the synthesis of steroid hormones such as testosterone, cortisol, and aldosterone?

• Conversion of cholesterol to pregnenolone

• Conversion of progesterone to 17-hydroxyprogesterone

• Conversion of 17-hydroxyprogesterone to cortisol

• Conversion of androstenedione to testosterone

What primarily regulates the activity of P450 aldosterone synthase (CYP11B2) in the zona glomerulosa of the adrenal cortex?

• Adrenocorticotropic hormone (ACTH)

• Cortisol levels

• Angiotensin II

• Epinephrine

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Which molecule binds to the cells in zona glomerulosa (zone 1) of the adrenal cortex to stimulate the synthesis and release of aldosterone?

• Adrenocorticotropic hormone (ACTH)

• Angiotensin II

• Cortisol

• Vasopressin (ADH)

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How does hyperkalemia affect aldosterone secretion in zona glomerulosa cells of the adrenal cortex?

• It depolarizes the cell membrane, opening voltage-gated Ca²⁺ channels and stimulating aldosterone secretion

• It inhibits Ca²⁺ channels, decreasing aldosterone release

• It blocks angiotensin II receptors, reducing aldosterone production

• It hyperpolarizes the cell membrane, preventing Ca²⁺ influx and aldosterone release

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How does cortisol regulate the hypothalamus-pituitary-adrenal (HPA) axis through negative feedback?

• It stimulates CRH release from the hypothalamus

• It promotes the secretion of renin by the kidneys

• It increases aldosterone secretion from the adrenal cortex

• It inhibits ACTH release from the anterior pituitary and CRH release from the hypothalamus

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What is the connection between low-density lipoprotein (LDL) and zona fasciculata (zone 2) cells of the adrenal cortex?

• LDL delivers cholesterol to zona fasciculata cells aiding in cortisol synthesis

• LDL inhibits cortisol production by zona fasciculata cells

• LDL stimulates aldosterone secretion in zona glomerulosa cells (zone 1)

• LDL is converted into angiotensin II in zona fasciculata cells

What is the effect of cortisol on glycogen storage in the liver?

• It decreases glycogen synthesis, leading to glycogen depletion

• It has no effect on liver glycogen levels

• It promotes glycogen synthesis and storage in the liver

• It stimulates glycogen breakdown in muscle only

How does cortisol affect the migration of polymorphonuclear leukocytes (PMNs) and the overall immune response?

• It enhances PMN migration to inflamed tissues, boosting the immune response

• It has no effect on PMN migration but increases cytokine production

• It increases PMN production and activation, strengthening immunity

• It inhibits PMN migration into tissues, leading to suppressed

What happens to the sympathetic nervous system if cortisol levels are low, considering its effect on PNMT in the adrenal medulla?

• Sympathetic nervous system activity increases due to more epinephrine

• Sympathetic nervous system activity decreases due to less epinephrine

• No change in sympathetic nervous system activity

• Sympathetic nervous system activity increases due to more norepinephrine

What would happen to epinephrine production in the adrenal medulla if cortisol were not produced by the adrenal cortex?

• Epinephrine production would decrease due to reduced stimulation of PNMT

• Epinephrine production would increase due to lack of cortisol inhibition

• Epinephrine production would remain unchanged

• Norepinephrine would be converted to epinephrine at a higher rate

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