Which of the following intravenous solutions is hypotonic?

Correct Answer: C

Rationale: The correct answer is C: 0.45% saline. This solution is hypotonic because it has a lower osmolarity compared to the intracellular fluid. It contains fewer solutes than the cells, causing water to move into the cells by osmosis, potentially causing them to swell. Normal saline (A) and Ringer's lactate (B) are isotonic solutions, meaning they have a similar osmolarity to the intracellular fluid and do not cause significant water shifts. 5% dextrose in normal saline (D) is a hypertonic solution, containing more solutes than the cells, leading to water movement out of the cells.

Correct Answer: C

Rationale: The correct answer is C: Laryngeal cancer. Persistent hoarseness is a common symptom of laryngeal cancer due to vocal cord involvement. Laryngeal cancer causes changes in voice quality over time. Bacterial infection (A) usually presents with acute symptoms and resolves with treatment. Aphonia (B) is the complete loss of voice, not persistent hoarseness. Peritonsillar abscess (D) causes sore throat and difficulty swallowing, but not persistent hoarseness.

Correct Answer: D

Rationale: The correct answer is D because pleural effusion is the accumulation of fluid in the pleural space. When auscultating the lungs of a client with pleural effusion, the examiner would note decreased or absent breath sounds over the area where the fluid has accumulated. This is due to the fluid blocking the transmission of sound through the lungs. Pronounced breath sounds (choice A) would not be present due to the fluid obstructing the normal sound transmission. Expiratory wheezes (choice B) are associated with airway obstruction, not fluid accumulation. Friction rub (choice C) is a dry, grating sound heard with inflammation of the pleura, not specifically related to pleural effusion.

Correct Answer: C

Rationale: The correct answer is C: Helper T cells. Helper T cells play a crucial role in activating B cells by releasing cytokines that stimulate B cell proliferation and differentiation. They also help in the production of antibodies. Cytotoxic T cells (A) are involved in cell-mediated immunity, not humoral immunity. Suppressor T cells (B) regulate the immune response and do not directly assist in B cell activation. Neutrophils (D) are phagocytic cells involved in innate immunity, not in activating B cells in humoral immunity.

Correct Answer: C

Rationale: Step-by-step rationale for choice C: Angioedema differs from urticaria as it involves deeper swelling in the dermis and subcutaneous tissue, leading to a more profound and firm texture. This contrasts with urticaria, which presents as superficial, raised wheals on the skin. Therefore, option C is correct. Summary of other choices: A: Angioedema is not typically associated with intense itching, so it is not more pruritic than urticaria. B: Angioedema does not have small, fluid-filled vesicles like in allergic contact dermatitis. D: Angioedema tends to last longer than urticaria, making this statement incorrect.