What structure separates the thoracic cavity from the abdominal cavity?

Correct Answer: B

Rationale: The diaphragm, a muscular sheet, divides the thoracic cavity housing lungs from the abdominal cavity with digestive organs. Nurses assess its movement like in breathing issues ensuring this barrier maintains cavity integrity. Unlike mediastinal or peritoneal roles, it's the key separator, critical for respiratory and abdominal health.

Correct Answer: D

Rationale: Serous membranes (A, C, E) line body cavities and secrete fluid (e.g., parietal peritoneum, visceral pleura, pericardium). Mesentery is a peritoneal fold, still serous-related. The mouth's lining is mucous membrane, secreting mucus, not serous fluid. Anatomically, serous reduces friction in cavities; mucous protects openings, making D the outlier.

Correct Answer: B

Rationale: Retroperitoneal means behind the peritoneum; kidneys are here, unlike stomach, appendix, and liver (E, intraperitoneal), or heart (C, thoracic). Anatomically, kidneys' posterior placement aids filtration, secured against the back wall, making B correct.

Correct Answer: A

Rationale: The parietal peritoneum lines the abdominal wall, cut first in appendectomy, unlike dorsal mesentery (B, organ support), visceral pleura, or parietal pleura (D, thoracic). Anatomically, it's the outer layer accessed surgically, making A correct.

Correct Answer: C

Rationale: Negative feedback loops output back to adjust input (e.g., thermostat), stabilizing conditions, unlike constant input, useless input, or constant output. Anatomically, this regulates temperature sweat cools maintaining homeostasis, confirming C.