Most people realize that vital organs begin to lose function with aging. Aging changes have been seen in all of the body's cells, tissues, and organs. These changes affect the functioning of all body systems. Living tissue is made up of cells. There are many different types of cells, but all have the same basic structure.
Tissues are layers of similar cells that perform a specific function.
The various kinds of tissue group together to form organs. Connective tissue supports other tissues and binds them together. This includes bone, blood, and lymph tissues in addition to the tissues that give support and structure to the skin and internal organs. Epithelial tissue provides a covering. It includes the skin, and the linings of the various passages inside the body.