In which of the following cases is dehydration more likely to occur?

Correct Answer: B

Rationale: Dehydration is more likely to occur in a 50-year-old man who is morbidly obese due to the increased risk of conditions like diabetes and heart disease that can lead to fluid imbalances. Being morbidly obese can also strain the body's systems, increasing the need for water. The other choices are less likely to experience dehydration as a primary concern. While being a bodybuilder may require strict hydration practices, dehydration is more prevalent in individuals with conditions like obesity.

Correct Answer: A

Rationale: The correct answer is Vitamin B12. Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of abnormally large and immature red blood cells. Lower extremity paresthesias, such as tingling or numbness, are common neurological symptoms associated with vitamin B12 deficiency. Folate deficiency can also cause megaloblastic anemia but is not typically linked to lower extremity paresthesias. Iron deficiency leads to microcytic anemia, not megaloblastic anemia. Vitamin K deficiency is associated with bleeding tendencies, not megaloblastic anemia or paresthesias.

Correct Answer: C

Rationale: The correct answer is C: Decline in kidney function. As people age, their kidneys may not work as effectively in conserving water and concentrating urine, leading to a higher risk of dehydration. Choice A is incorrect because more insensible losses do not directly relate to an increased risk of dehydration in the elderly. Choice B, an increase in muscle mass, is not a factor that leads to dehydration. Choice D, a decrease in fat, is also not a direct factor contributing to dehydration in the elderly.

Correct Answer: C

Rationale: Benign positional vertigo is typically triggered by changes in head position, such as bending forward or turning over in bed. This change in position leads to brief episodes of vertigo, often associated with nystagmus, which is rapid, involuntary eye movements. Pupillary changes and headaches are not typical features of benign positional vertigo, making choices B and A incorrect. Nystagmus in benign positional vertigo usually stops when the eyes fixate on an object, so choice D is also incorrect.

Correct Answer: A

Rationale: The correct answer is A. In active transport, energy is expended to move substances against their concentration gradient. Sodium moving out of cells and potassium moving into cells is an example of active transport because it requires energy to pump these ions across the cell membrane against their concentration gradients. Choices B, C, and D describe passive processes where substances move along their concentration gradients without the input of energy.

Correct Answer: A

Rationale: The correct answer is A. In the early stages of atheroma development, macrophages accumulate oxidized low-density lipoprotein (LDL) and transform into foam cells, leading to the formation of fatty streaks in the intima of blood vessels. This process is a hallmark of the initial stages of atherosclerosis. Choice B is incorrect as it describes the accumulation of lipids in the intima, which is a later event following foam cell formation. Choice C is also incorrect as it refers to the accumulation of proteins forming the fibrous cap, which occurs at a later stage to stabilize the atheroma. Choice D is incorrect as it describes the development of calcium and a necrotic lipid core, typically seen in advanced atherosclerosis rather than the early stages.

Correct Answer: D

Rationale: Anemia of chronic inflammation is typically characterized by normochromic (normal hemoglobin content) and normocytic (normal cell size) red blood cells. Choice A, hypochromic and microcytic, is incorrect because hypochromic refers to reduced hemoglobin content and microcytic refers to smaller than normal red blood cells, which are not typically seen in anemia of chronic inflammation. Choice B, hypochromic and macrocytic, is also incorrect as macrocytic refers to larger than normal red blood cells. Choice C, normochromic and microcytic, is incorrect because microcytic red blood cells are smaller than normal. Therefore, the correct classification for anemia of chronic inflammation is normochromic and normocytic.

Correct Answer: B

Rationale: The correct answer is B: Underexcretion of uric acid. In gouty arthritis, the crystallization within the synovial fluid of the affected joint is caused by the underexcretion of uric acid, leading to the accumulation and subsequent crystallization of urate crystals. Choice A, destruction of proteoglycans, is incorrect as it is not directly related to the crystallization process in gouty arthritis. Choice C, overexcretion of uric acid, is incorrect because gout is primarily associated with underexcretion or decreased excretion of uric acid rather than overexcretion. Choice D, increased absorption of uric acid, is also incorrect as the primary issue in gouty arthritis is the body's inability to properly eliminate uric acid.

Correct Answer: B

Rationale: The correct answer is a 45-year-old woman who is obese and has a menstrual pattern consisting of periods of amenorrhea and infrequent periods. Obesity and prolonged exposure to estrogen unopposed by progesterone due to infrequent ovulation are significant risk factors for endometrial cancer. Choices A, C, and D do not directly correlate with the increased risk of endometrial cancer. Postmenopausal status alone (Choice A), overweight with hypertension (Choice C), and smoking (Choice D) are not the primary risk factors for endometrial cancer.