Anatomical sacs are fluid-filled or air-filled cavities found in the body. CYSTS are sacs filled with fluid and can be found in various organs, such as the kidneys and ovaries. Ceca are blind-ended sacs located in the large intestine and are responsible for the absorption of water and electrolytes. BURSAE are small sacs filled with synovial fluid and are located between bones and tendons to reduce friction during movement.