Regarding Pneumothorax, one of the following isn't true?

Correct Answer: D

Rationale: Pneumothorax introduces air into the pleural space, negating intrapleural pressure (~-4 mmHg), collapsing the lung via elastic recoil and expanding the chest wall outward via its recoil increasing thoracic diameter, true. Venous return drops as positive pleural pressure (e.g., tension pneumothorax) compresses vena cava, reducing preload true. Vital capacity (VC) falls as collapsed lung limits exhalable volume (e.g., from 4-5 L) true. Lung compliance (C = ΔV / ΔP) doesn't increase collapsed lung tissue isn't more stretchable; compliance is a lung property unaffected by deflation, effectively zero in collapse, not raised. The false notion of increased compliance misrepresents pneumothorax, where pressure loss, not elasticity, drives effects, making it the untrue statement amid accurate mechanical outcomes.

Correct Answer: B

Rationale: The Coriolis effect is an apparent deflection of moving objects (e.g., air, water) due to Earth's rotation, not a true force but an inertial effect in a rotating frame. In the Northern Hemisphere, it deflects right; Southern, left proportional to velocity and latitude (2ωv sinφ). Gravity drives weight, not deflection false. Pressure gradients from solar heating drive winds, not Coriolis false. Friction (e.g., surface drag) opposes motion, not deflects false. Coriolis shapes weather patterns (e.g., cyclones), per geophysical fluid dynamics (e.g., Holton), making it the best description, distinct from physical forces or heating effects.

Correct Answer: C

Rationale: Thyroidectomy risks nerve injury near thyroid arteries. The internal laryngeal nerve (A, B) pierces the thyrohyoid membrane, unrelated to vocal cords (sensory above). The recurrent laryngeal nerve (D) innervates all intrinsic laryngeal muscles except cricothyroid, looping near the inferior thyroid artery, but C the external laryngeal nerve (branch of superior laryngeal) with the superior thyroid artery is key. It supplies the cricothyroid, which tenses vocal cords. Ligation here slackens the cord (weak voice), unlike D's paralysis (hoarseness, midline cord). C fits the symptoms.

Correct Answer: C

Rationale: A needle at the 9th intercostal space, midaxillary, below the lung's lower border (C), affects pleura (D), diaphragm (A), or spleen (B), but not the lung. C is correct.

Correct Answer: C

Rationale: Gastrulation, in the 3rd week (A), transforms the bilaminar embryo into trilaminar via epiblast migration (B), forming ectoderm, mesoderm (D, between ectoderm and endoderm), and endoderm. The primitive streak, however, appears in the epiblast (not hypoblast, C), initiating cell ingression. The hypoblast is displaced by endoderm and doesn't form the streak. C is false its misstatement of primitive streak location in the hypoblast, rather than epiblast, makes it the exception among accurate gastrulation facts.