2 Learning Outcomes (cont.) 25.1 Describe the functions of muscle.25.2 Compare the three types of muscle tissue including their locations and characteristics.25.3 Explain how muscle tissue generates energy.25.4 Describe the structure of a skeletal muscle.
3 Learning Outcomes (cont.) 25.5 Recognize the terms origin and insertion.25.6 Identify the major skeletal muscles of the body, giving the action of each.25.7 Summarize the changes that occur to the muscular system as a person ages.25.8 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.
4 Introduction Muscles contract and relax to cause movement 600 individual muscles in the bodyLearning Outcome: Describe the functions of muscle.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 The ability to contract enables muscles to Allow movementProvide stabilityControl body openings and passagesWarm the bodyLearning Outcome: Describe the functions of muscle.
6 Functions of Muscle (cont.) Skeletal musclesAttach to bones by tendonsContractions result in movementSmooth muscle – contractions move organ contentsCardiac muscle – contractions pump blood from the heartLearning Outcome: Describe the functions of muscle.MovementSkeletal muscles – cross joints. When these muscles contract, the bones they attach to move.Smooth muscle is found in the walls of various organs.Cardiac muscle of the heart produces the atrial and ventricular contractions that pump blood.Refer to CONNECT to see an animation about Muscle Contraction
7 Functions of Muscle (cont.) StabilityHold bones tightly togetherSmall muscles hold vertebrae togetherHeat ProductionHeat is released when muscles contractHelps maintain a normal temperatureLearning Outcome: Describe the functions of muscle.
8 Control of Body Openings and Passages SphinctersValve-like structuresControl movement in and out of passagesLearning Outcome: Describe the functions of muscle.Muscles also form valve-like structures around various body openings and passages.
9 Apply Your Knowledge RIGHT! F T T F F True or False: ___ Skeletal muscles are attached to bones by ligaments.___ Contractions of smooth muscle produce movement of organ contents.___ Cardiac muscle produces atrial and ventricular contractions.___ Sphincters control movement of substances out of passages.___ Heat is released as muscles relax.ANSWER:tendonsFTTin and outLearning Outcomes: Describe the functions of muscle.FRIGHT!Fcontract
10 Types of Muscle Tissue Muscle cells or myocytes – muscle fibers SarcolemmaSarcoplasmSarcoplasmic reticulumMyofibrilsLong structures in sarcoplasmStriations – arrangement of filamentsLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.Muscle cells or myocytes – called muscle fibers because of their long lengths.Sarcolemma – cell membrane of a muscle fiberSarcoplasm – the cytoplasm of muscle fibersSarcoplasmic reticulum – endoplasmic reticulumMyofibrils – long structures that fills most of the sarcoplasmStriations – produced by the arrangement of filaments in myofibrilsMuscle structure
11 BackLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
12 Types of Muscle Tissue (cont.) Muscle GroupMajor LocationMajor FunctionMode of ControlSkeletal MuscleAttached to bones and skin of the faceProduces body movements and facial expressionsVoluntarySmooth MuscleWalls of hollow organs, blood vessels, and irisMoves contents through organs; vasoconstrictionInvoluntaryCardiac MuscleWall of the heartPumps blood through heartLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
13 Skeletal Muscle Skeletal muscle fibers Contract in response to the neurotransmitter acetylcholineAfter contraction, muscles release the enzyme acetylcholinesteraseBreaks down acetylcholineAllows muscle to relaxLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
14 Smooth MuscleMultiunit smooth muscles – respond to neurotransmitters and hormonesVisceral smooth musclesResponds to neurotransmitters ~ acetylcholine and norepinephrineStimulate each other to contract ~ peristalsisLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.Multiunit smooth muscle – found in the iris of the eye and the walls of blood vessels.Visceral smooth muscleContains sheets of muscle cells that closely contact each other.Muscle fibers tend to contract and relax together producing an action called peristalsis.Found in the walls of hollow organs like the stomach, intestines, bladder, and uterus.
15 Cardiac Muscle Intercalated discs Self-exciting Connect groups of cardiac muscleAllow the heart to work as a pumpSelf-excitingResponds to neurotransmittersAcetylcholineNorepinephrineLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.Intercalated discs that have tunnels physically connect the cardiac muscle cells.They allow the fibers in that group to contract and relax together allowing the heart to work as a pump.The atria contract and relax togetherThen the ventricles contract to send blood to the lungs and body, after which they relax and the cycle starts again.Cardiac muscle is self-exciting and does not need nerve stimulation to contract.Nerves only speed up or slow down the contraction of the heart.Cardiac muscle responds to two neurotransmittersAcetylcholine slows the heart rateNorepinephrine speeds it up
16 Apply Your Knowledge Very Good! Match the following: ANSWER: ___ Self-exciting___ Contract in response to acetylcholine ___ Stimulate each other to contract___ Peristalsis___ Slowed by acetylcholine___ Voluntary movementANSWER:Skeletal MuscleSmooth muscleCardiac muscleCABLearning Outcome: Compare the three types of muscle tissue including their locations and characteristics.BVery Good!CA
17 Production of Energy for Muscle ATPMuscle cells make ATP byCreatine phosphate ~ rapid production of energyAerobic respiration ~ uses body’s store of glucoseLactic acid production from pyruvic acidLearning Outcome: Explain how muscle tissue generates energy.ATP (adenosine triphosphate) – a type of chemical energy needed for sustained or repeated muscle contractions.Muscle cells make this energy in three ways:Creatine phosphate productionWhen ATP is used during muscle contraction, it loses a phosphate and, therefore, energy.Creatine phosphate donates a phosphate group, restoring energy potential.Aerobic respirationCell breaks down the body’s store of glucose into pyruvic acid using oxygen stored in myoglobin to make ATP.Pyruvic acid is converted to acetyl coenzyme A.This begins a series of reactions called the Krebs cycle or citric acid cycle.Lactic acid productionOccurs when cell is low on oxygen and must convert pyruvic acid to lactic acid which is a waste product.This conversion produces a small amount of ATP for the cell.
18 Oxygen Debt Strenuous use of skeletal muscles depletes cells of oxygen Pyruvic AcidLactic acidTo liver for conversion to glucose, requiring more energy and oxygen to make ATPMuscle fatigueLearning Outcome: Explain how muscle tissue generates energy.When pyruvic acid is converted to lactic acid for energy production, the lactic acid builds up and causes muscle fatigue.The lactic acid is brought to the liver via the bloodstream to be converted back into glucose, which requires more energy.The amount of oxygen the liver cells need to make enough ATP for this conversion results in the oxygen debt.This process explains why your body still burns energy even after you are done exercising.Oxygen debt
19 Muscle Fatigue Loses ability to contract Causes Accumulation of lactic acidInterruption of the blood supplyAcetylcholine not released by motor neuronLearning Outcome: Explain how muscle tissue generates energy.Cramps often accompany muscle fatigue.
20 Yippee! Apply Your Knowledge ANSWER: Match the following: ___ Rapid production of energy ___ Needed for sustained or repeated muscle contractions ___ Uses body’s store of glucose ___ Muscle fatigue ___ With strenuous exercise, converts to lactic acidLactic acidPyruvic acidATPAerobic respirationCreatine phosphateECDLearning Outcome: Explain how muscle tissue generates energy.ABYippee!
21 Structure of Skeletal Muscles Skeletal muscles – the major organs of the muscular systemCompositionConnective tissueSkeletal muscle tissueBlood vesselsNervesLearning Outcome: Describe the structure of a skeletal muscle.
22 Structure of Skeletal Muscles (cont.) Connective tissue coveringsFasciaTendonAponeruosisEpimysiumPerimysiumEndomysiumLearning Outcome: Describe the structure of a skeletal muscle.The following connective tissue coverings are associated with skeletal musclesFasciaCovers entire skeletal musclesSeparates muscles from each other.TendonTough, cord-like structure made of fibrous connective tissueConnects muscles to bonesAponeurosisTough, sheet-like structure made of fibrous connective tissue.It typically attaches muscles to other muscles.EpimysiumA thin covering just deep to the fascia of a muscle.It surrounds the entire muscle.Perimysium – connective tissue that divides a muscle into sections called fascicles.Endomysium – connective tissue that surrounds individual muscle cells.Muscle structure
23 Apply Your Knowledge Excellent! D E A B F C Match the following: __ Thin covering under the fascia that surrounds the muscle__ Separates muscles from each other__ Connects muscles to bones__ Divides a muscle into sections called fascicles__ Surrounds individual muscle cells__ Attaches muscles to other musclesANSWER:DTendonPerimysiumAponeurosisEpimysiumFasciaEndomysiumEABLearning Outcome: Describe the structure of a skeletal muscle.FCExcellent!
24 Attachments and Actions of Skeletal Muscles Attachment typesOrigin ~ for a less movable boneInsertion ~ for a more movable boneLearning Outcomes: Recognize the terms origin and insertion..
25 Attachments and Actions of Skeletal Muscles (cont.) MovementPrime mover (agonist) ~ responsible for most of the movementSynergists ~ help the prime mover by stabilizing jointsAntagonist ~ produces movement opposite to prime moverLearning Outcome: Recognize the terms origin and insertion.Most of the time, body movement is produced by a group of muscles.An antagonist – must relax in order to produce a smooth body movement.
26 Attachments and Actions of Skeletal Muscles (cont.) Plantar flexionAbductionAdductionFlexionExtensionHyperextensionDorsiflexionLearning Outcome: 25.5 Recognize the terms origin and insertion.Flexion – bending a body part; decreasing the angle of a jointExtension – straightening a body part; increasing the angle of a jointHyperextension – extending a body part past the normal anatomical positionDorsiflexion – pointing the toes upPlantar flexion – pointing the toes downAbduction – moving a body part away from the midline of the bodyAdduction – moving a body part toward the midline of the bodyFigure of Body Movements
27 Hyperextension Extension Dorsiflexion Flexion Plantar flexion Learning Outcome: Recognize the terms origin and insertion.ExtensionAdductionFlexionAbductionBack
28 Attachments and Actions of Skeletal Muscles (cont.) RotationCircumductionPronationSupinationLearning Outcome: Recognize the terms origin and insertion.Rotation – twisting a body part; for example, turning your head from side to sideCircumduction – moving a body part in a circle; for example, moving your arm in a circular motionPronation – turning the palm of the hand down or lying face downSupination – turning the palm of the hand up or lying face upSupinationPronationRotationCircumduction
29 Attachments and Actions of Skeletal Muscles (cont.) InversionEversionRetractionProtractionElevationDepressionLearning Outcome: Recognize the terms origin and insertion.Inversion – turning the sole of the foot mediallyEversion – turning the sole of the foot laterallyRetraction – moving a body part posteriorlyProtraction – moving a body part anteriorlyElevation – lifting a body part; for example, elevating your shoulders as in a shrugging gestureDepression – lowering a body part; for example, lowering your shouldersIt is important to understand these movements to assist with judging and measuring the patients’ abilities to perform range of motion (ROM) exercises when assessing injuries and illnesses.Figure of movements
30 Attachments and Actions of Skeletal Muscles (cont.) ProtractionRetractionLearning Outcome: Recognize the terms origin and insertion.ElevationDepressionInversionEversionBack
31 Correct! Apply Your Knowledge F T T T True or false? An agonist is the muscle that produces a movement opposite to a prime mover.Synergists stabilize joints.Origin is an attachment site for the less moveable bone during muscle contraction.Insertion is an attachment site for the more moveable bone during muscle contraction.ANSWER:FantagonistTTLearning Outcome: Recognize the terms origin and insertion.TCorrect!
32 Major Skeletal Muscles Name often describes muscle byLocationSizeActionShapeNumber of attachmentsLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
33 Learning Outcome: 25.6 Identify the major skeletal muscles of the body, giving the action of each. Back
34 Muscles of the Head Sternocleidomastoid Splenius capitis Muscles of the jawMasseterTemporalisMuscles of facial expressionFrontalisOrbicularis orisOrbiuclaris oculiZygomaticusPlatysmaLearning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Sternocleidomastoid – pulls the head to one side and also pulls the head to the chest (sterno = sternum, cleido = clavicle, mastoid = mastoid).Splenius capitis – rotates the head and allows it to bend to the side. (capit = head)Muscles of facial expression include the following:Frontalis – raises the eyebrows.Orbicularis oris – allows the lips to pucker (oris = oro or mouth).Orbicularis oculi – allows the eyes to close (oculi = eye).Zygomaticus – pulls the corners of the mouth up (zygomat = cheekbone).Platysma – pulls the corners of the mouth down.The muscles of the jaw allow for mastication and include:Masseter – close the jaw (masseter – mastication or chewing).Temporalis. –close the jaw (temporo = temple).Skeletal muscles
35 Arm Muscles Pectoralis major Latissimus dorsi Deltoid Subscapularis InfraspinatusLearning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Muscles that move the arm include:Pectoralis major – pulls the arm across the chest; it also rotates and adducts the arms (pectoro = chest).Latissimus dorsi – acts to extend, adduct, and rotate the arm inwardly (latissimus = butterfly, dorsi = back).Deltoid – acts to abduct and extend the arm at the shoulder.Subscapularis – muscle rotates the arm medially (sub = below, scapulo = shoulder blade).Infraspinatus – rotates the arm laterally (infra = below, spinat = spine).Skeletal muscles
36 Arm Muscles (cont.) Biceps brachii Brachialis Brachioradialis Triceps brachiiSupinatorPronator teresLearning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Muscles that move the forearm include the following:Biceps brachii – flexes the arm at the elbow and rotates the hand laterally (bi = two, ceps = insertion, brachii = arm).Brachialis – flexes the arm at the elbow (brachii = arm).Brachioradialis – flexes the forearm at the elbow (brachii = arm, radio = radius).Triceps brachii – extends the arm at the elbow (tri = three, ceps = insertion, brachii = arm).Supinator – rotates the forearm laterally (supination) (supine = palm up).Pronator teres – rotates the forearm medially (pronation) (prone = palm down).Skeletal muscles
37 Muscles of the Wrist, Hand, and Fingers Flexor carpi radilasFelxor carpi ulnarisPalmaris longusFlexor digitorum profundusExtensor carpi radialis longus and brevisExtensor carpi ulnairsExtensor digitorumLearning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Muscles that move the wrist, hand, and fingers include the following:Flexor carpi radialis and flexor carpi ulnaris – flex and abduct the wrist (radio = radius, ulna = ulna).Palmaris longus – flexes the wrist.Flexor digitorum profundus – flexes the distal joints of the fingers but not the thumb (digits = fingers).Extensor carpi radialis longus and brevis – extend the wrist and abduct the hand (carpo = wrist, radio = radius, long = long, brev = brief or short).Extensor carpi ulnaris – extends the wrist (carpo = wrist, ulna = ulna).Extensor digitorum – extends the fingers but not the thumb (digit = finger).Diagram of hand
38 Learning Outcome: Learning Outcome: 25 Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Back
39 Respiratory Muscles Diaphragm Separates thoracic and abdominal cavitiesContracts for inspirationExternal and internal intercostals – expand and lower the ribsLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.External and internal intercostals – inter = between, costo = ribFor diagram
40 Skeletal Muscles (cont.) Abdominal musclesExternal and internal obliquesTransverse abdominisRectus abdominisMuscles of the Pectoral GirdleTrapeziusPectoralis minorLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Abdominal MusclesThe muscles of the abdominal wall include the following:External and internal obliques – compress the abdominal wall. (oblique = diagonal)Transverse abdominis – also compresses the abdominal wall. (transverse = across)Rectus abdominis – acts to flex the vertebral column and compress the abdominal wall. (rectus = erect)Muscles of the Pectoral GirdleThe muscles that move the pectoral girdle (shoulder) include:Trapezius – raises the arms and pulls the shoulders downward. (trapezius = trapezoid)Pectoralis minor – pulls the scapula downward and raises the ribs. (pectoro = chest, minor = smaller)For diagram
41 Skeletal Muscles (cont.) Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Back
42 Leg Muscles Iliopsoas major Gluteus maximus Gluteus medius and minimus Adductor longus and magnusLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.The leg muscles include muscles of the thigh and lower legIliopsoas major – flexes the thigh.Gluteus maximus – extends the thigh.Gluteus medius and minimus – abduct the thighs and rotate them medially.Adductor longus and magnus – adduct the thighs and rotate them laterally (adduct = toward the midline).Skeletal muscles
43 Leg Muscles (cont.)Biceps femoris, semitendinosus, and semimembranosusRectus femoris, vastus lateralis, vastus medialis, and vastus intermediusSartorisLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.The leg muscles include muscles of the thigh and lower legBiceps femoris, semitendinosus, and semimembranosusThese are known as the hamstring group.They act to flex the leg at the knee and extend the leg at the thigh.Rectus femoris, vastus lateralis, vastus medialis, and vastus intermediusThese four muscles are known as the quadriceps group.They act to extend the leg at the knee.SartoriusFlexes the leg at the knee and thighAbducts the thigh, rotating the thigh laterally but rotating the lower leg mediallyIt carries out the act of sitting cross-legged.Skeletal muscles
44 Ankle, Foot, and Toe Muscles Tibialis anteriorExtensor digitorum longusGastrocnemiusSoleusFlexor digitorum longusLearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.Muscles that move the ankle, foot, and toes include:Tibialis anterior – inverts the foot and points the foot up (dorsiflexion).Extensor digitorum longus – extends the toes and points the foot up.Gastrocnemius – calf muscleFlexes the footFlexes the leg at the knee.Soleus – also flexes the foot.Flexor digitorum longus – flexes the foot and toes.Skeletal muscles
45 Bravo! Apply Your Knowledge C F B E A D Matching: raises the eyebrows chewing expand and lower ribs compress the abdominal wall extends the thigh extends the leg at the kneeANSWER:Gluteus maximusIntercostalsFrontalisQuadriceps groupObliquesMasseterCFBELearning Outcome: Identify the major skeletal muscles of the body, giving the action of each.ADBravo!
46 Aging and the Musculoskeletal System Speed and strength of muscle contractions decreaseAgingDecreased dexterity and gripping abilityDecreased mobilityAssistive devices helpfulRoutine exerciseLearning Outcome: Summarize the changes that occur to the muscular system as a person ages.Aging of the skeletal systemCauses difficulties for patients with diseases and conditions like arthritis, fractures, and osteoporosis. Muscular decline often goes hand-in-hand with these changes.May causeIncreasing difficulty with dexterity and gripping ability.Decreasing mobility related to the combined decline of the musculoskeletal system.Diet, exercise history, and family history have a direct impact on the patient’s mobility and activity level as the patient ages.Assistive devices can help patients who are experiencing difficulties.Exercise routines, particularly pool exercises like swimming and physical therapy, are often helpful in maintaining strength and mobility.
47 Diseases and Disorders of the Muscular System DescriptionBotulismAffects the gastrointestinal tract and various muscle groupsFibromyalgiaFairly common condition that causes chronic pain primarily in joints, muscles, and tendonsMuscular dystrophyInherited disorder characterized by muscle weakness and a loss of muscle tissueMyasthenia gravisAutoimmune condition in which patients experience muscle weakness and loss of muscle tissueLearning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.BotulismCaused by the bacterium Clostridium botulinum which produces a toxin that can lead to a type of food poisoning.It may have long-lasting effects.FibromyalgiaThe causes are poorly understood.May be caused or exacerbated by sleep disturbance, emotional distress, decreased blood flow to muscles, a virus, or any combination of these factors.Muscular dystrophy (MD)The causes are primarily hereditary.Genetic fetal testing is available.Myasthenia gravis – an autoimmune condition in which a person produces antibodies that prevent muscles from receiving neurotransmitters from neurons.
48 Diseases and Disorders of the Muscular System (cont.) DescriptionRhabdomyolysisKidneys become damaged because of toxins released from muscle cells after serious muscle injuriesTendonitisPainful inflammation of a tendon and the tendon-muscle attachment to a boneTetanus (lockjaw)Muscle spasms in the jaw, keck and facial muscles; high mortality rateLearning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.Rhabdomyolysis – excessive amounts of myoglobin are released, which is then broken down into harmful chemicals.Tendonitis – usually occurs after a sports-related activity that results in injury to the muscle-tendon or tendon-bone attachment.Tetanus – a toxin produced by the bacterium Clostridium tetani which enters through open wounds caused by objects contaminated with soil.
49 Diseases and Disorders of the Muscular System (cont.) DescriptionTorticollis (wryneck)A cervical deformity in which the head bends toward the affected side while the chin rotates to the opposite sideTrichinosisAn infection caused by parasites ingested by eating undercooked meatLearning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.TorticollisCaused by spasm or shortening of the sternocleidomastoid muscle.Acquired or congenitalBreech or other difficult birth is often the cause of the congenital formThe acquired form is the result of underlying disease, cervical spine injury, or chronic muscle spasms.TrichinosisAn infection caused by parasitesWorms are usually ingested by eating undercooked meatWorms can leave the digestive tract and infect skeletal muscles, the heart, the lungs, and the brain.
50 Apply Your Knowledge Good Job! What changes occur to the muscular system as a result of aging?ANSWER: Speed and strength of muscle contractions decrease with aging.The aging process results in:Decreased dexterity and gripping abilityDecreased mobilityLearning Outcome: Describe the changes that occur to the muscular system as a person ages.Good Job!
51 Apply Your Knowledge Good Job! ANSWER: True or False: Botulism is a condition resulting in chronic pain in joints, muscles and tendons. Kidney damage due to toxins released by serious muscle injuries is the condition called rhabdomyolysis. Tetanus is caused by a toxin and causes muscle spasms in the jaw, neck, and facial muscles. Lockjaw is caused by spasm or shortening of the sternocleidomastoid muscle.FibromyalgiaFTTLearning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.TorticollisFGood Job!
52 In Summary25.1 The functions of muscles include movement, stability, control of body openings and passages, and the production of heat. Valve- like muscular structures called sphincters control passage of substances into and out of organs like the stomach and bladder.The three types of muscle tissue are striated, voluntary skeletal muscle; smooth, involuntary visceral muscle; and specialized striated and involuntary cardiac muscle.
53 In Summary (cont.)25.3 There are three ways muscles create energy. Creatine phosphate, aerobic respiration, and lactic acid production.25.4 Skeletal muscle is composed of connective tissues, skeletal muscle tissue, blood vessels, and nerves. The coverings of skeletal muscles include fascia, tendon, aponeurosis, epimysium, perimysium, and endomysium.25.3 There are three ways muscles create energy. Creatine phosphate is a rapid method for muscles to create energy; aerobic respiration uses stored glucose to produce ATP in the Krebs cycle; and lactic acid production occurs when a cell is low in oxygen and converts pyruvic acid to lactic acid.
54 In Summary (cont.)25.5 The origin of a muscle is the attachment site of the muscle to the less moveable bone during muscle contraction. The insertion of a muscle is the attachment site for the muscle to the more moveable bone during muscle contraction.25.6 The major muscles of the head and the upper extremity, major respiratory muscles, abdominal muscles, pectoral girdle muscles and those of the lower extremity are covered in this learning outcome.25.7 The major muscles of the head are sternocleidomastoid, splenius capitis, frontalis, orbicularis oris and oculi, zygomaticus, platysma, masseter, and temporalis.The upper extremity muscles include pectoralis major, latissimus dorsi, deltoid, subscapularis, biceps brachii, brachialis, brachioradialis, triceps brachii, supinator, pronator teres, flexor carpi radialis and ulnaris, plamaris longus, flexor digitorum profundus, extensor carpi radialis longus and brevis, extensor carpi ulnaris, and extensor digitorum.The major respiratory muscles are the diaphragm and the external and internal intercostals.The abdominal muscles include external and internal obliques, transverse abdominis, and rectus abdominis.The pectoral girdle muscles include trapezius and pectoralis minor.The muscles of the lower extremity include iliopsoas major; gluteus maximus, medius, and minimus; adductor longus and magnus; biceps femoris; semitendinosus and semimembranosus; rectus femoris; vastus lateralis, medialis, and intermedius; sartorius; tibialis anterior; extensor digitorum longus; gastrocnemius; soleus; and flexor digitorum longus.
55 In Summary (cont.)22.7 The common diseases of aging include arthritis, fractures, osteoporosis, and muscular decline. Aging causes a decline in strength and speed of muscle contractions. Dexterity and gripping abilities lessen and mobility often decreases related to skeletal and muscular decline.22.8 There are many common diseases and disorders of the muscular system with varied signs, symptoms, and treatments.22.8 There are many common diseases and disorders of the muscular system with varied signs, symptoms, and treatments. Some of these include: botulism, fibromyalgia, muscular dystrophy, myasthenia gravis, rhabdomyolysis, tendonitis, tetanus, torticollis, and trichinosis.
56 End of Chapter 25Everyone has a ‘risk muscle.’ You keep it in shape by trying new things. If you don’t, it atrophies. Make a point of using it at least once a day.~Roger von Oech