What Is the Function of the Musculatory System in a Cat?

Of the many organ systems in a cat, the musculatory system probably has the largest mass and uses the largest amount of energy. This reflects the importance of the musculatory system for the cat's survival. The functions of the musculatory system in a cat are much the same as in other higher-order organisms.

  1. Movement

    • The most obvious function of a cat's musculatory system is to allow for movement. As with other mammals, cats' muscles contract and relax through ATP-dependent excitation-contraction coupling. After receiving signals via nerve impulses originating from the brain and spinal cord, the muscle cell membranes depolarize. The calcium concentration within the muscle cells increases, and the myosin and actin filaments within the cell change structure to affect the shape of the muscle. Coordinated changes in muscular shape lead to movement. The ability to precisely move as a situation dictates can affect whether the cat is able to catch and eat its prey or run from a predatory.

    Structural Support

    • Tonically contracted and relaxed muscles allow for normal posture and body positioning. It is the static tone in the muscles that makes a cat not collapse or limp to the ground at any given moment, even when not in motion. In addition, muscles assist ligaments in providing support to joints. For example, the cat's deltoid muscles help to stabilize the front legs and prevent the bone from coming out of the socket when the cat must make a quick movement.

    Heat Production

    • Muscle contractions produce heat, a side effect of how ATP is used under excitation-contraction coupling. Although their fur is their most important protection against cold, cats sometimes shiver when exposed to cold temperatures. As in humans, the rhythmic contractions of muscle during shivering helps the body stay warm. The heat released during the contractions transfers into the blood, which then circulates to the rest of the body and provides protection against excessive cooling.

    Storage

    • As in humans, the musculatory system in a cat can function as a storage site for extra energy. Fat is normally the primary site for energy storage, but in conditions of starvation or food shortage, a cat's body can break down muscle proteins into amino acids for energy metabolism and gluconeogenesis. Even in normal conditions, the musculatory system produces and stores glycogen, an important fuel for the muscles during physical activity.