Which of the following decreases with normal aging?

The reason the sympathetic nervous system's response to stress decreases with normal aging is tied to the physiological changes that occur in the body over time. As individuals age, there is often a decline in the overall responsiveness of the autonomic nervous system, which includes the sympathetic nervous system. This system is responsible for the "fight or flight" response, including increasing heart rate, blood pressure, and metabolic rate during stressful situations.

Older adults may experience a blunted response to stress due to factors such as decreased neuron density and reduced receptor sensitivity, which can impact how effectively the body responds to stressors. This diminished response is part of the broader changes in physical health and homeostasis that can accompany aging.

In contrast, the other choices reflect processes or aspects that generally do not decrease with aging. Brain and spinal cord atrophy typically increases with age, leading to potential cognitive decline and mobility issues. The latency period in impulse transmission is typically prolonged rather than decreased, as nerve conduction velocity often slows down with age due to changes in myelin and axonal integrity. Therefore, the assertion that the sympathetic nervous system’s response decreases aligns accurately with the patterns observed in geriatric physiology.