The size of the motor unit. Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility diminishes quality of life and can lead to fall-related injuries which require costly hospitalization and extended rehabilitation. Associate Degree Nursing Physiology Review Physiology Exercise Physiology Body Systems Muscle tissues are soft tissues that make up the different types of muscles in most animals and give the ability of muscles to contractIt is also referred to as myopropulsive tissue. . As organs that contain cells that can contract muscles can generate force and movement. They are created during embryonic development in a process known as myogenesis. This review focuses on the aging-related structural changes and mechanisms at ce. These basic helix-loop-helix bHLH transcription factors regulate myogenesis. A myofibril also known as a muscle fibril or sarcostyle is a basic rod-like organelle of a m...