Which statement best describes emphysema?

Choice A reason: Abnormal tau proteins contribute to Alzheimer’s, forming neurofibrillary tangles, but damage is not limited to the frontal lobe. The hippocampus and other regions are primarily affected, leading to memory loss. This choice is too specific and incomplete, making it incorrect.

Choice B reason: Damaged blood vessels interrupting brain blood flow describe vascular dementia, not Alzheimer’s. Alzheimer’s involves neuronal degeneration from protein accumulation, not primarily vascular pathology, although vascular factors may contribute, making this choice incorrect for Alzheimer’s pathophysiology.

Choice C reason: Repeated traumatic brain injuries cause chronic traumatic encephalopathy, not Alzheimer’s. While trauma may increase Alzheimer’s risk, the primary pathology involves amyloid and tau proteins, not trauma-induced encephalopathy, making this choice incorrect for the disease’s core pathophysiology.

Choice D reason: Alzheimer’s disease is characterized by amyloid-beta plaques and tau protein tangles, which disrupt neuronal function, particularly in the hippocampus, leading to memory impairment. These protein aggregates cause synaptic loss and neurodegeneration, accurately describing the disease’s pathophysiology, making this the correct choice.

Choice A reason: Osteoporosis results from an imbalance where osteoclast-mediated bone resorption outpaces osteoblast-mediated bone formation, reducing bone density and strength. This leads to fragile, porous bones prone to fractures, especially in the elderly, due to hormonal changes or reduced calcium absorption, making this the correct description.

Choice B reason: An abnormal immune response causing synovitis and cartilage deterioration describes rheumatoid arthritis, not osteoporosis. Rheumatoid arthritis involves autoimmune inflammation of joints, not bone density loss. Osteoporosis primarily affects bone matrix, not cartilage or synovial tissues, making this choice incorrect.

Choice C reason: Cartilage erosion from mechanical stress describes osteoarthritis, a degenerative joint disease, not osteoporosis. Osteoporosis affects bone density, not articular cartilage. Mechanical stress may exacerbate joint issues but does not cause the systemic bone loss characteristic of osteoporosis, making this choice incorrect.

Choice D reason: A bacterial bone infection describes osteomyelitis, not osteoporosis. Osteomyelitis involves localized bone inflammation and destruction due to pathogens, not a systemic imbalance of bone remodeling. Osteoporosis is a metabolic condition, not an infectious one, making this choice incorrect for the described pathophysiology.