A 74-year-old woman is admitted to the hospital in an obtunded condition. Her temperature is 37°C, pulse is 95/min, respirations are 22/min, and blood pressure is 90/60 mm Hg. She appears dehydrated and has poor skin turgor. Her serum glucose level is 872 mg/dL. Urinalysis shows 4+ glucosuria, but no ketones, protein, or blood. Which of the following factors is most important in the pathogenesis of this patient's condition?

Correct Answer: D

Rationale: A complication of type 2 diabetes mellitus is hyperosmolar, nonketotic coma. In type 2 diabetes mellitus, the fundamental defect is insulin resistance, leading to an eventual decrease in plasma insulin or a relative lack of insulin, but there is still enough insulin to prevent ketosis. The resulting hyperglycemia tends to produce polyuria, leading to dehydration, which increases the serum glucose level further.

Correct Answer: C

Rationale: AP triggers vesicle fusion, releasing ACh into cleft; then Na+ channels open, AChE acts later.

Correct Answer: D

Rationale: All occur: S1 marks AV closure, pressure rise, isovolumetric phase, QRS.

Correct Answer: D

Rationale: Capillaries reabsorb fluid via oncotic pressure at venous end.

Correct Answer: A

Rationale: IgA in breast milk provides passive mucosal immunity to newborns.