Effects of Aging on brain

Effects of Aging 
After age 60, the brain begins to lose thousands of neurons I a day. When these cells die, they are not replaced. By age 80, the brain weighs about 10% less than when the person was a young adult. The cerebral cortex shrinks more than other areas of the brain, losing as much as 45% of its cells. Therefore, such mental activities as learning, memory, and reasoning decline.
Neurotransmitter production also decreases, resldlting in slower synaptic transmission. As a person ages, thought processing and translating a thought into action take longer. This explains why younger athletes tend to out­shine older athletes in sports.
Alzheimer disease is usually associated with age. The progres­sive loss of memory and other intellectual functions in Alzheimer patients is accompanied by abnormalities in neuron structure. The neurons develop neurofibrillary tangles and amyloid plaques, perhaps as a result of a genetic defect.