Tissue changes refer to alterations in the structure or composition of biological tissues, which can occur due to various factors such as injury, disease, or aging. These changes can affect the function of the tissue, leading to symptoms or health issues. For example, inflammation can cause swelling and pain, while fibrosis may lead to stiffening of tissues. Common types of tissue changes include atrophy, where tissues shrink or weaken, and hypertrophy, where tissues enlarge due to increased workload. Additionally, metaplasia involves the transformation of one type of tissue into another, often as a response to chronic irritation or injury.