Juvenile rheumatoid arthritis (JRA) primarily affects which type of tissue?

Juvenile rheumatoid arthritis (JRA) primarily affects connective tissue, particularly the joints and surrounding structures. Connective tissue is essential for providing support and structure to various parts of the body, which includes cartilage and ligaments found in joints. In JRA, the immune system incorrectly attacks the synovial lining of the joints, leading to inflammation and damage to the connective tissue structures within the joints. This inflammatory process can also affect other connective tissue throughout the body, resulting in symptoms such as pain, swelling, and reduced mobility in pediatric patients. Understanding the role of connective tissue in JRA is crucial for recognizing the impact of this condition on joint function and overall quality of life for affected individuals. The other types of tissue mentioned do not play a primary role in this condition, as nervous tissue is related to the nervous system, muscle tissue is involved in movement, and epithelial tissue covers body surfaces and lines cavities, none of which are the focus in the context of JRA.