1 Ramutkowski  Booth  Pugh  Thompson  Whicker Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MUSCULAR SYSTEM Ms. Marta Valdes, Instructor

2 Objectives 26-1List the functions of muscle. 26-2Explain how muscle tissue generates energy List the three types of muscle tissue and describe the locations and characteristics of each Describe how smooth muscle produces peristalsis Describe the structure of a skeletal muscle. The Muscular System

3 Objectives (cont.) 26-7List and define the various types of body movements produced by skeletal muscles. 26-8Define the terms origin and insertion. 26-9List the major skeletal muscles of the body and give the action of each Describe various disorders and diseases of the muscular system. The Muscular System

4 Introduction  Bones and joints do not themselves produce movement.  The human body has more than 600 individual muscles  By alternating between contraction and relaxation, muscles cause bones and supported structures to move. You will focus on the differences among three muscle tissue types, the structure of skeletal muscles, muscle actions, and the names of skeletal muscles.

5 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

6 Skeletal Muscle

7 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.

8 Functions of Muscle  Stability:  Muscles hold your bones together to stabilize joints.  Small muscles hold your vertebrae together to stabilize your spinal column.

9 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

10 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.

3 Types of Muscles

12 3 Types of Muscle Tissue Muscle Group Major LocationMajor FunctionMode of Control Skeletal Muscle Attached to bones and skin of the face Produces body movements and facial expressions Voluntary Smooth Muscle Walls of hollow organs, blood vessels, and iris Moves contents through organs; vasoconstriction Involuntary Cardiac Muscle Wall of the heartPumps blood through heart Involuntary

13 Peristalsis  Rhythmic contraction that pushes substances through tubes of the body.  The muscle fibers tend to contract and relax together.  This type of muscle produces an action called peristalsis.

14 Production of Energy for Muscle  Muscle cells must have three ways to store or make this substance:  Creatine phosphate  Aerobic respiration of glucose  Lactic acid production ATP (adenosine triphosphate), a type of chemical energy, is needed for sustained or repeated muscle contractions.

Where Does the Energy Come From?  Energy is stored in the muscles in the form of ATP  ATP comes from the breakdown of glucose during Cellular Respiration  This all happens in the Mitochondria of the cell  When a muscle is fatigued (tired) it is unable to contract because of lack of Oxygen

16 Oxygen Debt  Oxygen debt develops when skeletal muscles are used strenuously for a minute or two and:  supplies in the muscle are low  the aerobic respiration of glucose can no longer be used to produce ATP.  This process accounts for why you still burn energy after you exercise.

17 Muscle Fatigue  Condition in which a muscle has lost its ability to contract  Develops due to an accumulation of lactic acid  Occurs when the blood supply to a muscle is interrupted  A motor neuron loses its ability to release acetylcholine onto muscle fibers  Cramps or painful involuntary contractions of muscles, can accompany muscle fatigue

18 Apply Your Knowledge What causes bones to move?

19 Answer Apply Your Knowledge - Answer Bones move by alternating between contraction and relaxation; muscles cause bones and supported structures to move. What causes bones to move?

20 Structure of Skeletal Muscles  Skeletal muscles are the major organs that make up the muscular system  Consists of connective tissues, skeletal muscle tissue, blood vessels, and nerves  When body movements are produced, not just one muscle is involved, but a group of muscles contract

21 Connective Tissue Coverings  Fascia  Fascia - covers entire skeletal muscles and separates them from each other.  Tendon  Tendon - a tough, cord-like structure made of fibrous connective tissue that connects muscles to bones.  Aponeurosis  Aponeurosis - a tough, sheet-like structure made of fibrous connective tissue that attaches muscles to other muscles.  Epimysium  Epimysium - a thin covering that is just deep (underneath) to the fascia of a muscle that surrounds the entire muscle.  Perimysium fascicles  Perimysium - connective tissue divides a muscle into sections called fascicles.  Endomysium  Endomysium - covering of connective tissue surrounds individual muscle cells.

22 Attachments and Actions of Skeletal Muscles  Actions of skeletal muscles depend largely on what the skeletal muscles are attached  Insertion - an attachment site that moves when a muscle contracts.  Origin - an attachment site that does not move when a muscle contracts

Muscle Attachments Origin Insertion

24 Body Movements Flexion Flexion – Bending a body part Extension Extension – Straightening a body part Hyperextension Hyperextension – Extending a body part past the normal anatomical position Dorsiflexion Dorsiflexion – Pointing the toes up Plantar flexion Plantar flexion – Pointing the toes down Abduction Abduction – Moving a body part away from its position in the anatomical position Adduction Adduction – Moving a body part toward its position in the anatomical position

Flexion Types of Musculo-Skeletal Movement

Extension

Hyperextension

Abduction, Adduction & Circumduction

. ROTATION

30 Body Movements (cont.) Circumduction Circumduction- Moving a body part in a circle; for example, moving your arm in a circular motion Pronation Pronation – Turning the palm of the hand down Supination Supination – Turning the palm of the hand up Inversion Inversion – Turning the sole of the foot medially Eversion Eversion – Turning the sole of the foot laterally Retraction Retraction – Moving a body part posteriorly Protraction Protraction – Moving a body part anteriorly

31 (cont.) Body Movements (cont.) Elevation Elevation – Lifting a body part; for example, elevating the shoulders as in a shrugging expression Depression Depression – Lowering a body part; for example, lowering the shoulders

32 Apply Your Knowledge The doctor has asked you to abduct the patient’s leg, so he can see the patient’s wound. In order to position the patient correctly what will you have to do?

33 Answer Apply Your Knowledge - Answer Moving the patient’s leg away from its position in the anatomical position. The doctor has asked you to abduct the patient’s leg, so he can see the patients wound. In order to position the patient correctly what will you have to do?

34 Major Skeletal Muscles  The muscle name indicates the location, size, action, shape, or number of attachments of the muscle.  As you study muscles, you will find it easier to remember them if you think about what the name describes.

35 Muscles of the Head  Sternocleidomastoid  Sternocleidomastoid - pulls the head to one side and also pulls the head to the chest  Splenius capitis  Splenius capitis - rotates the head and allows it to bend to the side  Frontalis  Frontalis - raises the eyebrows  Orbicularis oris  Orbicularis oris - allows the lips to pucker  Orbicularis oculi  Orbicularis oculi - allows the eyes to close  Zygomaticus  Zygomaticus - pulls the corners of the mouth up  Platysma  Platysma - pulls the corners of the mouth down  Masseter temporalis  Masseter and temporalis - close the jaw

36 Arm Muscles  Pectoralis major  Pectoralis major - pulls the arm across the chest; it also rotates and adducts the arms  Latissimus dorsi  Latissimus dorsi - acts to extend, adduct, and rotate the arm inwardly  Deltoid  Deltoid - acts to abduct and extend the arm at the shoulder  Subscapularis  Subscapularis - rotates the arm medially  Infraspinatus  Infraspinatus - rotates the arm laterally

37 Forearm Muscles  Biceps brachii  Biceps brachii - flexes the arm at the elbow and rotates the hand laterally  Brachialis  Brachialis - flexes the arm at the elbow  Brachioradialis  Brachioradialis - flexes the forearm at the elbow  Triceps brachii  Triceps brachii - extends the arm at the elbow  Supinator  Supinator - rotates the forearm laterally (supination)  Pronator teres  Pronator teres - rotates the forearm medially (pronation)

38 Muscles of the Wrist, Hand and Fingers  Flexor carpi radialis and flexor carpi ulnaris  Flexor carpi radialis and flexor carpi ulnaris - act to flex and abduct the wrist.  Palmaris longus  Palmaris longus - acts to flex the wrist.  Flexor digitorum profundus  Flexor digitorum profundus - acts to flex the distal joints of the fingers but not the thumb.  Extensor carpi radialis longus and brevis  Extensor carpi radialis longus and brevis - act to extend the wrist and abduct the hand.  Extensor carpi ulnaris  Extensor carpi ulnaris - acts to extend the wrist.  Extensor digitorum  Extensor digitorum - acts to extend the fingers but not the thumb.

39 Respiratory Muscles  Diaphragm  Diaphragm - separates the thoracic cavity from the abdominal cavity; its contraction causes inspiration.  External and internal intercostals - muscles expand and lower the ribs during breathing.

40 Apply Your Knowledge A patient has arrived in the office complaining of pain when she raises her arm. What muscle would be involved in this action?

41 Answer Apply Your Knowledge - Answer The deltoid muscle acts to abduct and extend the arm at the shoulder. A patient has arrived in the office complaining of pain when she raises her arm. What muscle would be involved in this action?

42 Abdominal Muscles  External and internal obliques  External and internal obliques - compress the abdominal wall.  Transverse abdominis  Transverse abdominis - also compresses the abdominal wall.  Rectus abdominis  Rectus abdominis - acts to flex the vertebral column and compress the abdominal wall. Click for Larger View

43 Abdominal Muscles (cont.)

44 Muscles of the Pectoral Girdle  Trapezius  Trapezius - muscle raises the arms and pulls the shoulders downward.  Pectoralis minor  Pectoralis minor - muscle pulls the scapula downward and raises the ribs.

45 Leg Muscles  Psoas major & iliacus  Psoas major & iliacus - flexes the thigh.  Gluteus maximus  Gluteus maximus - extends the thigh.  Gluteus mediusminimus  Gluteus medius and minimus - abduct the thighs and rotate them medially.  Adductor longusmagnus  Adductor longus and magnus - muscles adduct the thighs and rotate them laterally.  Biceps femoris, semitendinosus semimembranosus  Biceps femoris, semitendinosus, and semimembranosus - three muscles are known as the hamstring group. They act to flex the leg at the knee and extend the leg at the thigh.

46 Leg Muscles (cont.)  Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius  Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius - act to extend the leg at the knee.  Sartorius  Sartorius - flexes the leg at the knee and thigh and abducts the thigh, rotating the thigh laterally but rotating the lower leg medially.

47 Muscles of the Ankle, Foot, and Toes  Tibialis anterior  Tibialis anterior - acts to invert the foot and point the foot up (dorsiflexion).  Extensor digitorum longus  Extensor digitorum longus - acts to extend the toes and point the foot up.  Gastrocnemius  Gastrocnemius - acts to flex the foot and flex the leg at the knee.  Soleus  Soleus - also acts to flex the foot.  Flexor digitorum longus  Flexor digitorum longus - acts to flex the foot and toes.

48 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?

49 Answer Apply Your Knowledge - Answer 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. 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?

50 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.

51 Diseases and Disorders of the Muscular System  Botulism  Botulism - affects the gastrointestinal tract and various muscle groups  Fibromyalgia  Fibromyalgia - fairly 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

52 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  Trichinosis - an infection caused by parasites (worms)

53 Apply Your Knowledge The doctor has told your patient that his son has muscular dystrophy disorder. What is muscular dystrophy?

54 Answer Apply Your Knowledge - Answer Muscular dystrophy is an inherited disorder characterized by muscle weakness and a loss of muscle tissue. The doctor has told your patient that his son has muscular dystrophy disorder. What is Muscular dystrophy?

55 Summary 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.

Copyright © 2010 Ryan P. Murphy

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