Androgen is secreted by

Correct Answer: C

Rationale: Androgens, mainly testosterone, are secreted by the testes' Leydig cells, activated by pituitary LH, making the testes the source. FSH regulates sperm, not androgens. GnRH from the hypothalamus triggers LH/FSH release, indirectly affecting androgens. The pituitary releases LH/FSH, not androgens. The testes' direct secretion role is fundamental, driven by LH, distinguishing it from regulatory hormones.

Correct Answer: A

Rationale: Warfarin, an anticoagulant, inhibits vitamin K-dependent clotting factors. Spinach is high in vitamin K, which can counteract warfarin's effect, reducing its efficacy and increasing clot risk if consumed in large amounts. The nurse must instruct avoidance to maintain therapeutic INR levels. Potatoes and bananas have minimal vitamin K and don't significantly affect warfarin. Chicken is protein-rich, not vitamin K-rich, posing no issue. Consistent vitamin K intake is key, but large amounts of spinach could destabilize anticoagulation, risking thrombus progression. This aligns with warfarin's pharmacodynamics, where dietary education prevents therapeutic failure. Potatoes, bananas, and chicken lack this interaction, making spinach the priority to limit. Thus, A is the correct choice, ensuring the client understands how to support treatment efficacy and safety through diet management.

Correct Answer: A

Rationale: The reticular activating system (RAS) in the brainstem regulates sleep-wake cycles, promoting alertness or rest, per neurophysiology. The cortex processes thought, not cycles. The limbic system drives emotion, not sleep directly. The cerebellum coordinates movement. RAS's role is central, controlling consciousness states.

Correct Answer: B

Rationale: EMLA (Eutectic Mixture of Local Anesthetics) is a commonly used topical local anesthetic cream. It contains a combination of lidocaine and prilocaine. This combination of local anesthetics work together to provide effective pain relief when applied to the skin before certain medical procedures like needle insertion, laser treatment, or minor skin surgeries. Lidocaine and prilocaine work by blocking nerve signals in the skin, reducing sensations of pain and discomfort in the area where the cream is applied.

Correct Answer: A

Rationale: Antiseptics and disinfectants exert their bactericidal/bacteriostatic effects through various mechanisms, including: