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Chapter 26 - The muscular system. Bones and joints do not themselves produce movement. By alternating between contraction and relaxation, muscles cause bones and supported structures to move. The human body has more than 600 individual muscles. Although each muscle is a distinct structure, muscles act in groups to perform particular movements. This chapter focuses on the differences among three muscle tissue types, the structure of skeletal muscles, muscle actions, and the names of skeletal muscles.
PowerPoint® to accompany Medical Assisting Chapter 26 Second Edition Ramutkowski Booth Pugh Thompson Whicker Copyright © The McGraw-Hill Companies, Inc Permission required for reproduction or display The Muscular System Objectives 261 List the functions of muscle. 262 Explain how muscle tissue generates energy 263 List the three types of muscle tissue and describe the locations and characteristics of each 264 Describe how smooth muscle produces peristalsis 265 Describe the structure of a skeletal muscle The Muscular System Objectives (cont.) 267 List and define the various types of body movements produced by skeletal muscles 268 Define the terms origin and insertion 269 List the major skeletal muscles of the body and give the action of each 2610 Describe various disorders and diseases of the muscular system. Introduction Bones and joints do By alternating between not themselves contraction and produce movement. relaxation, muscles cause bones and The human body has supported structures to more than 600 move individual muscles You will focus on the differences among three muscle tissue types, the structure of skeletal muscles, muscle actions, and the names of skeletal muscles. Functions of Muscle Muscle has the ability to contract, and this contraction allows muscles to perform various functions Functions: Movement Stability Control of body openings and passages Heat production Click for Larger View Skeletal Muscle Functions of Muscle Movement: Skeletal muscles are attached to bones which allow you to walk or wave your hand Smooth muscle is found on organ walls such as the intestine. Contractions produces movement of food through the intestine Cardiac muscle produces the pumping of the blood in the heart Functions of Muscle Stability: Muscles hold your bones together to stabilize joints Small muscles hold your vertebrae together to stabilize your spinal column Functions of Muscle Controlling of openings and passages: Muscles form valve like structures called sphincters Sphincters control movement of substances in and out of passages A urethral sphincter prevents or allows urination Functions of Muscle Heat production: When muscles contract heat is released This helps the body maintain a normal temperature Moving your body can make you warmer if you are cold 10 Abdominal Muscles External and internal obliques compress the abdominal wall Transverse abdominis also compresses the abdominal wall Rectus abdominis acts to flex the vertebral column and compress the abdominal wall Click for Larger View 34 Abdominal Muscles (cont.) 35 Muscles of the Pectoral Girdle Trapezius muscle raises the Trapezius arms and pulls the shoulders downward Pectoralis minor muscle Pectoralis minor pulls the scapula downward and raises the ribs 36 Leg Muscles Psoas major & iliacus flexes the thigh Psoas major & iliacus Gluteus maximus extends the thigh Gluteus maximus Gluteus medius and minimus abduct the Gluteus medius minimus thighs and rotate them medially Adductor longus and magnus muscles adduct Adductor longus magnus the thighs and rotate them laterally Biceps femoris, semitendinosus, and Biceps femoris, semitendinosus semimembranosus three muscles are known as semimembranosus the hamstring group. They act to flex the leg at the knee and extend the leg at the thigh 37 Leg Muscles (cont.) Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius act to vastus intermedius extend the leg at the knee Sartorius flexes the leg at the Sartorius knee and thigh and abducts the thigh, rotating the thigh laterally but rotating the lower leg medially 38 Muscles of the Ankle, Foot, and Toes Tibialis anterior acts to invert the foot and point Tibialis anterior the foot up (dorsiflexion) Extensor digitorum longus acts to extend the Extensor digitorum longus toes and point the foot up. Gastrocnemius acts to flex the foot and flex the Gastrocnemius leg at the knee Soleus also acts to flex the foot Soleus Flexor digitorum longus acts to flex the foot and Flexor digitorum longus toes 39 Apply Your Knowledge Your patient complains of hurting his hamstring when running today. You would look at what part of the leg, and what muscles would be involved? 40 Apply Your Knowledge Answer Your patient complains of hurting his hamstring when running today. You would look at what part of the leg, and what muscles would be involved? You would look at the back of his leg, and the muscles involved would be the biceps femoris, semitendinosus, and semimembranosus. These three muscles are known as the hamstring group. 41 Muscle Strains and Sprains Warm Up – Warming up muscles for just a few minutes before an intense activity raises muscle temperature. Stretch – Stretching improves muscle performance and should always be done after the warm up or after exercising. Cool Down – Slowing down the exercise before completely stopping prevents dizziness and fainting. 42 Diseases and Disorders of the Muscular System Botulism affects the Botulism gastrointestinal tract and various muscle groups Fibromyalgia fairly Fibromyalgia common condition that causes chronic pain primarily in joints, muscles, and tendons Muscular Dystrophy Muscular Dystrophy inherited disorder characterized by muscle weakness and a loss of muscle tissue Myasthenia gravis Myasthenia gravis patients experience muscle weakness 43 Diseases and Disorders of the Muscular System Rhabdomyolysis Rhabdomyolysis a condition in which the kidneys have been damaged related to serious muscle injuries Tetanus Tetanus commonly called lockjaw Trichinosis an Trichinosis infection caused by parasites (worms) 44 Apply Your Knowledge The doctor has told your patient that his son has muscular dystrophy disorder. What is muscular dystrophy? 45 Apply Your Knowledge Answer The doctor has told your patient that his son has muscular dystrophy disorder. What is Muscular dystrophy? Muscular dystrophy is an inherited disorder characterized by muscle weakness and a loss of muscle tissue. 46 Summary Medical Assistant Skeletal muscle works in conjunction with the skeletal system to produce movement. You must understand the muscular system in order to give muscular injections, prepare patients for massage therapy, demonstrate ambulatory techniques, and assist in the care of sprains and strains 47 End of Chapter 48 ... Objectives 26 1 List the functions of muscle. 26 2 Explain how muscle tissue generates energy 26 3 List the three types of muscle tissue and describe the locations and characteristics of each 26 4 Describe how smooth muscle produces peristalsis... movements produced by skeletal muscles 26 8 Define the terms origin and insertion 26 9 List the major skeletal muscles of the body and give the action of each 26 10 Describe various disorders and diseases of the muscular system. ... 26 4 Describe how smooth muscle produces peristalsis 26 5 Describe the structure of a skeletal muscle The Muscular System Objectives (cont.) 26 7 List and define the various types of body movements produced by skeletal muscles 26 8 Define the terms origin and insertion