Tissues are groups of similar cells that do the same thing in the body. There are four main types of tissue: epithelial, muscle, connective and nerve. Epithelial tissue is what covers the body surfaces and lines its cavities and tubes. Some epithelial tissue is specialized to form glands like oil and sweat glands in the skin. Muscles tissue helps in body movement because it can contract and relax. There are three different types of muscle tissue: smooth, cardiac, and skeletal. Smooth muscle tissue is what lines the insides of the internal organs and blood vessels. Cardiac muscle tissue is found in the walls of the heart. Skeletal muscle tissue forms the muscles which are attached to the bones, these muscles are voluntary, which means they can be controlled with conscious thought, and they help us to walk, run, or move our body in some other way. The smooth and cardiac muscle tissue are involuntary, which means they are not controlled by conscious thought, they work automatically. Connective tissue provides support throughout the body. The main purpose of connective tissue is to join together the other tissues of the body. It connects the bone to the muscle with tendons, and the bones to other bones with ligaments. It also can keep two bones from rubbing together, like the cartilage between the vertebrae in the spinal column and the joints. Nerve tissue gives your body control. It sends out signals for information and processes data coming into the brain from different areas of the body. Some scientists also consider the blood and lymph fluid to be tissue, it is responsible for carrying nutrients all through the body, carrying waste products, and special cells that help the body fight infection and disease.
