All vital organs begin to lose some function as you age. Aging changes have been found in all of the body's cells, tissues, and organs, and 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 different kinds of tissues group together to form organs.
There are four basic types of tissue:
•Connective tissue supports other tissues and binds them together. This includes bone, blood, and lymph tissues, as well as the tissues that give support and structure to the skin and internal organs.
•Epithelial tissue provides a covering for deeper body layers. The skin and the linings of the passages inside the body, such as the gastrointestinal system, are made of epithelial tissue.
•Muscle tissue includes three types of tissue:◦Striated muscles, such as those that that move the skeleton (also called voluntary muscle)
◦Smooth muscles (also called involuntary muscle), such as the muscles contained in the stomach and other internal organs
◦Cardiac muscle, which makes up most of the heart wall (also an involuntary muscle)
•Nerve tissue is made up of nerve cells (neurons) and is used to carry messages to and from various parts of the body. The brain, spinal cord, and peripheral nerves are made of nerve tissue.