Which hormone is responsible for regulating calcium levels in the blood?

Correct Answer: D

Rationale: Parathyroid hormone (PTH) adjusts blood calcium, mobilizing it from bones when low. Unlike metabolic or sex hormones, it's a calcium gatekeeper. Nurses monitor it in bone health like osteoporosis ensuring skeletal and systemic balance.

Correct Answer: B

Rationale: The mitochondrion, a cell's energy producer, is an organelle, not an organ (A, tissue group), cell (C, whole unit), or tissue (D, cell group). Organelles are anatomy's intracellular specialists, and mitochondria's role in ATP synthesis exemplifies their functional importance, making B correct.

Correct Answer: B

Rationale: The calf is distal (farther from attachment) to the knee, which is proximal (closer to thigh attachment). It's not deep (A, depth-related), proximal, or both. Distal aligns with anatomy's limb terminology, marking the calf below the knee.

Correct Answer: D

Rationale: Muscles are deep (beneath) the skin, which is superficial (surface). They're not lateral (A, side), superficial, or superior (C, above). Depth terms in anatomy clarify layering, like muscles under skin, essential for understanding body structure.

Correct Answer: C

Rationale: Axillary refers to the armpit, not acromial (A, shoulder), brachial (B, arm), or sternal (D, chest). Anatomical terms like axillary pinpoint regions, vital for procedures like lymph node checks, confirming C.