Scientific Knowledge Flashcards
7 cards from real Physician Assistant practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Scientific Knowledge flashcards as text
Which pharmacokinetic parameter describes the fraction of an administered drug that reaches systemic circulation unchanged?
Answer: Bioavailability (F)
Bioavailability (F) quantifies the proportion of an administered dose that reaches systemic circulation, accounting for first-pass metabolism and absorption.
The complement system's membrane attack complex (MAC) is formed by which terminal complement components?
Answer: C5b-9
The MAC is assembled from C5b through C9, forming a pore in the target cell membrane that causes osmotic lysis.
In a patient with metabolic alkalosis, which compensatory mechanism would you expect?
Answer: Hypoventilation to retain CO2
Metabolic alkalosis is compensated by hypoventilation, which retains CO2 and increases carbonic acid to buffer the elevated pH.
Which neurotransmitter is released at the neuromuscular junction to initiate skeletal muscle contraction?
Answer: Acetylcholine
Acetylcholine is released from motor neuron terminals and binds nicotinic receptors on the motor end plate, triggering muscle depolarization.
Which vitamin requires intrinsic factor for absorption and is deficient in pernicious anemia?
Answer: Vitamin B12 (cobalamin)
Vitamin B12 binds intrinsic factor produced by gastric parietal cells for absorption in the terminal ileum; autoimmune destruction of parietal cells causes pernicious anemia.
The zone of inhibition in a Kirby-Bauer disk diffusion test is used to determine which microbiological property?
Answer: Antibiotic susceptibility of a bacterial isolate
The Kirby-Bauer test measures zones of inhibited bacterial growth around antibiotic-impregnated disks to classify organisms as susceptible, intermediate, or resistant.
Preload in cardiac physiology refers to which hemodynamic parameter?
Answer: End-diastolic ventricular volume (or pressure)
Preload represents the degree of ventricular stretch before contraction, best approximated by end-diastolic volume, and follows the Frank-Starling mechanism.