Jonas comes into the local blood donation center. He says he is here to donate platelets only today. The nurse knows this process is called:

Correct Answer: C

Rationale: Apheresis is the process of selectively collecting specific blood components, such as platelets, while returning the remaining components to the donor. This method allows for the efficient collection of platelets without depleting the donor's red blood cells or plasma. Directed donation refers to donating blood for a specific recipient, autologous donation involves donating one's own blood for future use, and allogeneic donation is the standard donation for the general blood supply. Therefore, apheresis is the correct term for platelet-only donation.

Correct Answer: B

Rationale: Penicillins cross the blood-brain barrier mainly when meninges are inflamed (e.g., meningitis), a true statement due to increased permeability. They do require dose adjustment in renal failure, as they're renally excreted, making the lack of adjustment false and the exception. They inhibit bacterial cell wall synthesis by blocking peptidoglycan cross-linkage, a true mechanism. Piperacillin is effective against Pseudomonas, especially with tazobactam, which is true. Only 5-10% of those with prior penicillin allergy react again, also true. The renal adjustment need is critical, as accumulation risks toxicity like seizures, guiding safe prescribing in kidney dysfunction.

Correct Answer: C

Rationale: Androgens, primarily testosterone, are secreted by the testes' Leydig cells, stimulated by luteinizing hormone (LH) from the pituitary, making the testes the direct source. Follicle-stimulating hormone (FSH) from the pituitary regulates sperm production, not androgen secretion. Gonadotropin-releasing hormone (GnRH) from the hypothalamus triggers pituitary LH and FSH release, indirectly influencing androgen production, not secreting it. The pituitary releases LH and FSH, not androgens itself. The testes' role as the endocrine organ producing androgens is clear, driven by LH, and is fundamental to male reproductive and secondary sexual characteristics, setting it apart from regulatory hormones in the hypothalamic-pituitary-gonadal axis.

Correct Answer: C

Rationale: A P450 enzyme inducer (e.g., rifampin) speeds metabolism of itself and other drugs, reducing its own effect over time as levels drop faster, requiring dose adjustments. No effect on others is extreme-some drugs' metabolism increases, lowering their effect. Increased effects suggest inhibition, not induction. Self-induction lowers efficacy, a pharmacokinetic principle affecting long-term use.

Correct Answer: B

Rationale: Aging reduces liver/renal clearance, raising plasma levels (e.g., digoxin), heightening response and toxicity risk, per pharmacokinetics. Body water drops, concentrating drugs, not diluting. Doses decrease, not increase-metabolism slows. Absorption may slow, but pH rises, not falls. Plasma increase drives effects, key in elders.