MUSCULAR TISSUE

Adipose Connective Tissue Adipose tissue is “fatty tissue.” The adipose cell at first appears star-shaped. When the cell begins to store fat in its cytoplasm, it enlarges, losing its star shape as the nucleus is pushed to one side (fig. 1-7). When this process occurs to many cells, the other cell types are crowded out and adipose tissue is formed. Adipose tissue is found beneath skin, between muscles, and around joints and various organs of the body. Adipose tissue acts as a reservoir for energy-producing foods; helps to reduce body heat loss (because of its poor heat conductivity); and serves as support for various organs and fragile structures, such as the kidneys, blood vessels, and nerves. Osseous Connective Tissue This type of tissue, known as “bone tissue,” is a dense fibrous connective tissue that forms tendons, ligaments, cartilage, and bones (fig. 1-8). These tissues form the supporting framework of the body. MUSCULAR TISSUE Muscular tissue provides for all body movement. Contracting muscles cause body parts to move. The three types of muscle tissue are skeletal, smooth, and cardiac. Skeletal Muscle Tissue Skeletal (voluntary) muscle fiber is striated, or striped, and is under the control of the individual's will (fig. 1-9). For this reason, it is often called “voluntary” muscle tissue. Skeletal muscle tissues are usually attached to bones. When muscle fibers are stimulated by an action of a nerve fiber, the fibers contract and relax. This interaction between muscle and nervous fibers produces movement. Smooth Muscle Tissue These muscle fibers are smooth, or nonstriated, and are not under the control of the individual's will (fig. 1-10). For this reason, this type of muscle tissue is called “involuntary.” Smooth muscle tissue is found in the walls of hollow organs, such as the stomach, intestines, blood vessels, and urinary bladder. Smooth muscle tissues are responsible for the movement of food through the digestive system, constricting blood vessels, and emptying the bladder. 1-5 CELL MEMBRANE FAT DROPLET NUCLEUS HM3F0107 Figure 1-7.—Adipose connective tissue. HM3F0108 Figure 1-8.—Osseous (bone) connective tissue. HM3F0109 Figure 1-9.—Skeletal muscle tissue. HM3F0110 Figure 1-10.—Smooth muscle tissue.