ATI RN
ATI Pharmacology Study Guide Questions
Question 1 of 5
Which substance has the lowest rate of crossing renal tubular membranes and would therefore be excreted in the urine?
Correct Answer: C
Rationale: Ionized drugs cross renal tubular membranes poorly, staying in urine for excretion, unlike non-ionized or lipid-soluble drugs reabsorbed easily. Volatile drugs (e.g., anesthetics) excrete via lungs, not kidneys. Ionization traps drugs, a pharmacokinetic excretion key.
Question 2 of 5
An important function of calcium is to
Correct Answer: D
Rationale: Calcium regulates nerve transmission-e.g., neurotransmitter release, per physiology-not acid-base (HCO3-), glucose (insulin), or energy (ATP). Nerve function is key, per role.
Question 3 of 5
A 6-year-old boy cuts his hand on the training wheel of his bicycle. The wound is 1.5 cm in size and the bleeding stops with direct pressure. One of the steps of blood clotting involved platelet aggregation through activation of collagen. Platelet release of granules is mediated by the release of mediators. Which of the following mediators, if activated, will likely cause bleeding to continue?
Correct Answer: C
Rationale: Platelet aggregation stops bleeding, but serotonin is correct-if defective, bleeding persists. ADP , Thrombin , and Thromboxane A2 (E) promote clotting. Dopamine is unrelated. Serotonin's vasoconstrictive role, if impaired, could prolong bleeding, though less critical than others here.
Question 4 of 5
A 28-year-old female presents with a 4 × 5 cm purulent ulcer on her abdomen following a spider bite. A wound culture grows MRSA, so intravenous vancomycin is started. While receiving her first dose of vancomycin, her face, neck, and chest flushed red. This reaction can best be described as
Correct Answer: A
Rationale: Vancomycin's red man syndrome-flushing during infusion-is non-hypersensitivity mast cell degranulation . Rapid infusion triggers histamine release, not IgE-mediated allergy . Type II , III , and IV (E) involve immune mechanisms unrelated to this acute, rate-dependent reaction. Slowing infusion prevents it, distinguishing it from true hypersensitivity, aligning with vancomycin's pharmacology in MRSA treatment.
Question 5 of 5
Midazolam is an effective anesthetic because it acts by
Correct Answer: D
Rationale: Midazolam is a short-acting benzodiazepine widely used as an anesthetic due to its rapid onset and potent sedative effects. Its mechanism involves enhancing the activity of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain, at GABA_A receptors—not GABA_B receptors, which are linked to different effects like muscle relaxation. By binding to a specific site on the GABA_A receptor, midazolam increases the frequency of chloride channel opening, leading to greater chloride ion conductance into neurons. This hyperpolarizes the neuron, making it less excitable and producing sedation, anxiolysis, and anesthesia. Dopamine enhancement is unrelated to its action, as is NMDA receptor blockade, which is a feature of drugs like ketamine. Partial agonism at serotonin (5HT) receptors also does not apply here. The facilitation of GABA-mediated chloride conductance is the precise mechanism that underpins midazolam's clinical utility as an anesthetic agent.