How does aging generally affect the kidney and/or bladder?

As individuals age, several physiological changes occur within the renal system, particularly affecting the bladder. One significant change is that the bladder's capacity to hold urine generally decreases. This reduced capacity can lead to more frequent urination and a sense of urgency, as the bladder does not store urine as effectively as it once did.

This is attributed to changes in the bladder wall's elasticity and the function of the muscles that control bladder function, both of which can be affected by the aging process. As a result, older adults may notice a necessity to urinate more often, especially at night, which can impact their overall quality of life.

In contrast, the kidneys do not typically become larger; instead, kidney size may decrease with age. Additionally, the kidneys also generally have a decreased ability to filter blood efficiently as part of the aging process. Therefore, the other options presented do not accurately capture the physiological changes that occur in the kidneys and bladder with aging.