NU 641 Quiz 1 Questions With Complete
Solutions
Course
NU641
1. What is the primary mechanism of action of beta-blockers?
Answer: Beta-blockers block beta-adrenergic receptors, reducing heart rate and
contractility.
Explanation: By inhibiting the effects of epinephrine and norepinephrine, beta-blockers
lower blood pressure and decrease myocardial oxygen demand, making them useful in
hypertension and heart failure.
2. Which enzyme is responsible for breaking down acetylcholine in the synaptic cleft?
Answer: Acetylcholinesterase.
Explanation: Acetylcholinesterase degrades acetylcholine into choline and acetate,
terminating neurotransmission at cholinergic synapses.
3. What is the primary site of action of loop diuretics?
Answer: The thick ascending limb of the loop of Henle.
Explanation: Loop diuretics (e.g., furosemide) inhibit the Na⁺/K⁺/2Cl⁻ cotransporter,
leading to increased sodium and water excretion, making them effective for treating
edema and hypertension.
4. Which neurotransmitter is most commonly associated with mood regulation and
depression?
Answer: Serotonin (5-HT).
Explanation: Low serotonin levels are linked to depression, and selective serotonin
reuptake inhibitors (SSRIs) increase serotonin availability in synapses to improve mood.
5. What is the primary physiological effect of aldosterone?
, Answer: Aldosterone increases sodium and water retention while promoting potassium
excretion.
Explanation: It acts on the distal tubules and collecting ducts of the kidney, regulating
blood pressure and electrolyte balance.
6. What is the mechanism of action of proton pump inhibitors (PPIs)?
Answer: PPIs irreversibly inhibit the H⁺/K⁺ ATPase enzyme in gastric parietal cells,
reducing stomach acid production.
Explanation: PPIs (e.g., omeprazole) are used to treat GERD, peptic ulcers, and Zollinger-
Ellison syndrome.
7. What is the primary role of insulin in glucose metabolism?
Answer: Insulin facilitates glucose uptake into cells by increasing GLUT4 transporter
activity.
Explanation: Insulin lowers blood glucose levels and promotes glycogen storage in liver
and muscle tissues.
8. What type of drug is most commonly used for acute asthma exacerbations?
Answer: Short-acting beta-agonists (SABAs), such as albuterol.
Explanation: SABAs relax bronchial smooth muscle by stimulating beta-2 adrenergic
receptors, providing rapid relief of bronchoconstriction.
9. Which organ is the primary site of drug metabolism?
Answer: The liver.
Explanation: The liver metabolizes drugs via Phase I (cytochrome P450 enzymes) and
Phase II (conjugation reactions) pathways, making drugs more water-soluble for
excretion.
10. What is the primary effect of angiotensin II on blood pressure?
, Answer: Angiotensin II causes vasoconstriction and stimulates aldosterone release,
increasing blood pressure.
Explanation: It plays a key role in the renin-angiotensin-aldosterone system (RAAS) and
is targeted by ACE inhibitors and ARBs to lower blood pressure.
11. What is the mechanism of action of ACE inhibitors?
Answer: ACE inhibitors block the conversion of angiotensin I to angiotensin II.
Explanation: By reducing angiotensin II levels, these drugs lower blood pressure by
preventing vasoconstriction and decreasing aldosterone secretion.
12. Which electrolyte imbalance is most commonly associated with loop diuretics?
Answer: Hypokalemia.
Explanation: Loop diuretics promote potassium excretion, which can lead to muscle
weakness and cardiac arrhythmias.
13. What is the main function of glucagon?
Answer: Glucagon raises blood glucose by stimulating glycogen breakdown in the liver.
Explanation: It is released by pancreatic alpha cells in response to low blood sugar.
14. How do statins lower cholesterol levels?
Answer: Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol
synthesis.
Explanation: This leads to increased LDL receptor expression in the liver, enhancing LDL
clearance from the blood.
15. What is the most common adverse effect of opioids?
Answer: Respiratory depression.
Solutions
Course
NU641
1. What is the primary mechanism of action of beta-blockers?
Answer: Beta-blockers block beta-adrenergic receptors, reducing heart rate and
contractility.
Explanation: By inhibiting the effects of epinephrine and norepinephrine, beta-blockers
lower blood pressure and decrease myocardial oxygen demand, making them useful in
hypertension and heart failure.
2. Which enzyme is responsible for breaking down acetylcholine in the synaptic cleft?
Answer: Acetylcholinesterase.
Explanation: Acetylcholinesterase degrades acetylcholine into choline and acetate,
terminating neurotransmission at cholinergic synapses.
3. What is the primary site of action of loop diuretics?
Answer: The thick ascending limb of the loop of Henle.
Explanation: Loop diuretics (e.g., furosemide) inhibit the Na⁺/K⁺/2Cl⁻ cotransporter,
leading to increased sodium and water excretion, making them effective for treating
edema and hypertension.
4. Which neurotransmitter is most commonly associated with mood regulation and
depression?
Answer: Serotonin (5-HT).
Explanation: Low serotonin levels are linked to depression, and selective serotonin
reuptake inhibitors (SSRIs) increase serotonin availability in synapses to improve mood.
5. What is the primary physiological effect of aldosterone?
, Answer: Aldosterone increases sodium and water retention while promoting potassium
excretion.
Explanation: It acts on the distal tubules and collecting ducts of the kidney, regulating
blood pressure and electrolyte balance.
6. What is the mechanism of action of proton pump inhibitors (PPIs)?
Answer: PPIs irreversibly inhibit the H⁺/K⁺ ATPase enzyme in gastric parietal cells,
reducing stomach acid production.
Explanation: PPIs (e.g., omeprazole) are used to treat GERD, peptic ulcers, and Zollinger-
Ellison syndrome.
7. What is the primary role of insulin in glucose metabolism?
Answer: Insulin facilitates glucose uptake into cells by increasing GLUT4 transporter
activity.
Explanation: Insulin lowers blood glucose levels and promotes glycogen storage in liver
and muscle tissues.
8. What type of drug is most commonly used for acute asthma exacerbations?
Answer: Short-acting beta-agonists (SABAs), such as albuterol.
Explanation: SABAs relax bronchial smooth muscle by stimulating beta-2 adrenergic
receptors, providing rapid relief of bronchoconstriction.
9. Which organ is the primary site of drug metabolism?
Answer: The liver.
Explanation: The liver metabolizes drugs via Phase I (cytochrome P450 enzymes) and
Phase II (conjugation reactions) pathways, making drugs more water-soluble for
excretion.
10. What is the primary effect of angiotensin II on blood pressure?
, Answer: Angiotensin II causes vasoconstriction and stimulates aldosterone release,
increasing blood pressure.
Explanation: It plays a key role in the renin-angiotensin-aldosterone system (RAAS) and
is targeted by ACE inhibitors and ARBs to lower blood pressure.
11. What is the mechanism of action of ACE inhibitors?
Answer: ACE inhibitors block the conversion of angiotensin I to angiotensin II.
Explanation: By reducing angiotensin II levels, these drugs lower blood pressure by
preventing vasoconstriction and decreasing aldosterone secretion.
12. Which electrolyte imbalance is most commonly associated with loop diuretics?
Answer: Hypokalemia.
Explanation: Loop diuretics promote potassium excretion, which can lead to muscle
weakness and cardiac arrhythmias.
13. What is the main function of glucagon?
Answer: Glucagon raises blood glucose by stimulating glycogen breakdown in the liver.
Explanation: It is released by pancreatic alpha cells in response to low blood sugar.
14. How do statins lower cholesterol levels?
Answer: Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol
synthesis.
Explanation: This leads to increased LDL receptor expression in the liver, enhancing LDL
clearance from the blood.
15. What is the most common adverse effect of opioids?
Answer: Respiratory depression.
