202 Anatomy & Physiology Essentials Copyright Goodheart-Willcox Co., Inc. Medical Terminology: The Muscular System By understanding the word parts that make up medical words, you can extend your medical vocabulary. This chapter includes many of the word parts listed below. Review these word parts to be sure you understand their meanings. -al pertaining to -bradia slowness -clonus twitching dorsi- back dys- bad, difficult, abnormal flex/o bend or flex -genesis birth, formation of -ion process leio- smooth muscul/o muscle my/o muscle myom/o muscle tumor mysi/o muscle fiber neur/o nerve peri- surrounding -trophy condition of Now use these word parts to form valid medical words that fit the following definitions. Some of the words are included in this chapter. Others are not. When you finish, use a medical dictionary to check your work. 1. surrounding a muscle (fiber) 2. process of bending backward 3. condition of abnormal muscles 4. pertaining to both a muscle and a nerve 5. formation of a muscle 6. pertaining to both the muscles and the skeleton 7. tumor in smooth muscle 8. process of bending 9. muscle twitching 10. muscle slowness Chapter 6 Summary • The three major categories of muscle fibers are smooth, cardiac, and skeletal (striated). • Muscles are either voluntary or involuntary and have four common behavioral characteristics: extensibility, elasticity, irritability, and contractility. • Skeletal muscles work in an agonist/antagonist relationship and can experience concentric, eccentric, or isometric contractions. • The motor unit is the functional unit of the neuromuscular system and is made up of the neuron and the muscle fibers that the neuron stimulates. • Skeletal muscle fibers are classified as fast-twitch fibers, which are powerful and fatigue quickly, and slow-twitch fibers, which are fatigue-resistant. • Sagittal plane movements are forward and back- ward actions frontal plane movements take the body part toward or away from the midline of the body and transverse plane movements are actions that move side to side or rotate around a longitudinal axis. • The muscles of the head and neck can be divided into three groups: facial muscles, chewing muscles, and neck muscles. • The trunk muscles provide stability for the vertebral column and help maintain posture. • The upper limb sacrifices stability for increased range of motion compared with the lower limb. • The lower limb is designed for its primary jobs of standing and walking. • Muscle development begins before birth and continues into adulthood. • Causes of muscular injuries include sports mishaps, accidents, and overuse of muscles during everyday activities. • Common muscle disorders include muscular dystrophy and hernias. Chapter 6 Review Understanding Key Concepts 1. The individual skeletal muscle cell is referred to as a(n) _____. 2. The _____ bundles groups of muscle fibers to create fascicles. 3. Skeletal muscle is connected to bone by either _____ or aponeuroses. 4. _____ muscle is found in organs and blood vessels. 5. The heart is made up of _____ muscle cells.