Organs may interact to form organ systems, such as the digestive system. General Characteristics Epithelial tissue is commonly called epithelium. In epithelial tissues, cells are linked tightly together, with little intervening material. Glandular Epithelium Glands are single cells or multicelled secretory structures. Endocrine glands secrete hormones directly into intercellular fluid for distribution by the blood.
Cartilage contains a dense array of fibers in a jellylike ground substance.
Locations include the ends of bones, parts of the nose, external ear, and disks between vertebrae. Bone stores mineral salts, produces blood cells, and provides spaces for its own living osteocytes. Bones work with muscles to perform movement. Adipose tissue cells are specialized for the storage of fat, which can be used as an energy reserve and as cushions to pad organs. Muscle Tissue Muscle tissue contracts in response to stimulation, then passively lengthens.