Atrophy refers to the gradual decline or wasting away of a body part, often due to lack of use, injury, or disease. This process can affect muscles, organs, or tissues, leading to reduced function and strength. For example, when a person is immobilized for a long time, such as after a surgery, the muscles may weaken and shrink. Atrophy can also occur in the brain, where it may be associated with conditions like Alzheimer's disease or Parkinson's disease. In these cases, the loss of neurons can impact cognitive abilities and overall brain function. Early intervention and rehabilitation can help mitigate some effects of atrophy.