minggu 4 & 5 sistem otot

8/14/2019 MINGGU 4 & 5 SISTEM OTOT

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Three Types of Muscle Tissues

Skeletal Muscle• usually

attached to

bones

• under

conscious

control

• striated

Smooth Muscle

• walls of most viscera,

blood vessels, skin• not under conscious

control

• not striated

Cardiac Muscle• wall of heart

• not under

conscious

control

• striated

Chapter 9 - Muscular SystemChapter 9 - Muscular System



Skeletal Muscle• organ of the muscular

system

• skeletal muscle tissue• nervous tissue

• blood

• connective tissues

• fascia

• tendon• aponeuroses

Structu re o f a S keletaltructu re o f a S keletal

Muscleuscle



• epimysium

• perimysium

• fascicle• endomysium

• muscle

• fascicles• muscle fibers

• myofibrils

• thick and thin filaments


Muscleuscle



• sarcolemma

• sacroplasm

• sarcoplasmic reticulum

• transverse tubule

• triad• cisterna of sarcoplasmic

reticulum

• transverse tubule

• myofibril• actin filaments

• myosin filaments

• sarcomere

Sk elet al M uscle Fi berk elet al M uscle Fi ber




Muscleuscle



• I band

• A band

• H zone

• Z line

• M line

Sa rcomer ea rcomer e



Thick Filaments

• composed of myosin

• cross-bridges

Thin Filaments• composed of actin

• associated with troponin

and tropomyosin

Myofila men tsyofila men ts



• site where axon and

muscle fiber

communicate• motor neuron

• motor end plate

• synaptic cleft

• synaptic vesicles

• neurotransmitters

Neu ro mu sc ular J unctioneu ro mu sc ular J unction



• single motor neuron

• all muscle fibers controlled by motor neuron

Mo tor U nito tor U nit



• acetylcholine (ACh)

• nerve impulse causes release

of acetylcholine from synapticvesicles

• binds to acetylcholine

receptors on motor end plate

• generates a muscle impulse

• muscle impulse eventuallyreaches sarcoplasmic

reticulum

St imu lu s for Con tra ct io nt imu lu s for Con tra ct io n



9-11

• muscle impulses cause

sarcoplasmic reticulum to

release calcium ions intocytosol

• calcium binds to troponin to

change its shape

• position of tropomyosin is

altered• binding sites on actin

exposed

• actin and myosin bind

Exci tati on Co ntra ction C ou pli ngxci tati on Co ntra ction C ou pli ng



• When sarcromeres

shorten, thick and thin

filaments slide past oneanother

• H zones and I bands

get narrower

• Z lines move closer

together

Slid in g Fila men t Th eorylid in g Fila men t Th eory



• actin and myosin

cross-bridge bind

• myosin cross-

bridge pulls actin

•ADP and phosphatereleased from myosin

• new ATP binds to

myosin

•linkage between actinand myosin cross-bridge

break

•ATP splits

•myosin cross-bridge goes back

to original position

Cros s-b rid ge Cy clin gros s-b rid ge Cy clin g



• creatine phosphate – stores energy that quickly converts

ADP to ATP

1) Creatine phosphate 2) Cellular respiration

Energy So urces fo rnergy So urces fo r

Co ntra cti ono ntra cti on



• Anaerobic Phase• glycolysis

• produces little ATP

• Aerobic Phase• citric acid cycle

• electron transport

chain

• produces most ATP • myoglobin stores extra

oxygen

Oxyg en Suppl y a ndxyg en Suppl y a nd

Cellula r R esp ir ati onellula r R esp ir ati on



• oxygen not available

• glycolysis continues

• pyruvic acid

converted to lactic acid

• liver converts lactic

acid to glucose

Oxygen debt – amount of oxygen needed by liver to convert

lactic acid to glucose

Oxygen Debtxygen Debt



• inability to contract

• commonly caused from

• decreased blood flow• ion imbalances

• accumulation of lactic acid

• cramp – sustained, involuntary contraction

Muscle Fa tig ueuscle Fa tig ue



• by-product of cellular respiration

• muscle cells are major source of body heat• blood transports heat throughout body

Hea t P rod uct ionea t P rod uct ion



Threshold Stimulus

• minimal strength required to cause contraction

Recording a MuscleContraction

• twitch

• latent period

• period of contraction

• period of relaxation

• refractory period

• all-or-none response

Muscu la r R es pon sesuscu la r R es pon ses



• process by which individual twitches combine

• produces sustained contractions

• can lead to tetanic contractions

Summationummation



• recruitment - increase in the number of motor units

activated

• whole muscle composed of many motor units

• as intensity of stimulation increases, recruitment of

motor units continues until all motor units are

activated

Recr uitm ent of Moto r Un itsecr uitm ent of Moto r Un its



• smaller motor units recruited first

• larger motor units recruited later

• produces smooth movements

• muscle tone – continuous state of partial contraction

Su sta in ed Con tract ion su stain ed Con tract ion s



• isotonic – muscle contracts and

changes length

• concentric – shortening contraction

• eccentric – lengthening

contraction

• isometric – muscle contracts but

does not change length

Ty pes of Co ntract ion sy pes of Co ntract ion s



Slow-twitch fibers (type I)

• always oxidative

• resistant to fatigue

• red fibers

• most myoglobin

• good blood supply

Fast-twitch glycolytic fibers (type II)• white fibers (less myoglobin)

• poorer blood supply

• susceptible to fatigue

Fast-twitch fatigue-

resistant fibers (type

IIb)• intermediate fibers

• oxidative

• intermediate

amount of

myoglobin• pink to red in color

Fa st a nd Sl ow Twitc ha st a nd Sl ow Twitc h

Musc le Fi bersusc le Fi bers



Visceral Smooth Muscle

• single-unit smooth

muscle• sheets of muscle fibers

• fibers held together by

gap junctions

• exhibit rhythmicity

• exhibit peristalsis

• walls of most hollow

organs

Multiunit Smooth Muscle

• fibers function separately

• irises of eye• walls of blood vessels

Types of Smoot h M uscleypes of Smoot h M uscle



• Resembles skeletal muscle contraction• interaction between actin and myosin

• both use calcium and ATP

• both depend on impulses

• Different from skeletal muscle contraction• smooth muscle lacks troponin

• smooth muscle depends on calmodulin

• two neurotransmitters affect smooth muscle

• acetlycholine and norepinephrine• hormones affect smooth muscle

• stretching can trigger smooth muscle contraction

• smooth muscle slower to contract and relax

• smooth muscle more resistant to fatigue

Smooth Mu scl e Co ntra cti onmooth Mu scl e Co ntra cti on



• only in the heart

• muscle fibers joined together by intercalated discs

• fibers branch• network of fibers contracts as a unit

• self-exciting and rhythmic

• longer refractory period than skeletal muscle

Card ia c M uscleard ia c M uscle



9-30

• origin – immovable end

• insertion – movable end

• prime mover (agonist) –

primarily responsible formovement

• synergists – assist prime

mover

• antagonist – resist primemover’s action and cause

movement in the opposite

direction

Sk elet al M uscle Act ion sk elet al M uscle Act ion s



Major S kelet al M uscle sajor S kelet al M uscle s



Mus cl es o f F ac ia l E xpr essi onus cl es o f F ac ia l E xpr essi on



Muscles of M ast ica tionuscles of M ast ica tion



Muscl es of Fa ci aluscl es of Fa ci al

Exp ress io n an d Mas ticati onxp ress io n an d Mas ticati on



usc es a ove evHead a nd V erte bra lead a nd V erte bra l

Columnolumn



Musc les T hat Move theusc les T hat Move the

Pector al Gir dl eector al Gir dl e




Ar mr m



9-39

Dee p Musc les o f th eee p Musc les o f th e

Ba ck a nd Necka ck a nd Neck



Musc les o f th e An te riorusc les o f th e An te rior

Ch est a nd Ab do mi nal Wal lh est a nd Ab do mi nal Wal l




Fo rear mo rear m




Handan d



Muscl es of theuscl es of the

Shoul der a nd A rmhoul der a nd A rm



Cros s Sect ion of t heros s Sect ion of t he

Armrm




Shoul der a nd A rmhoul der a nd A rm




Arm a nd Fo rea rmrm a nd Fo rea rm



Cr oss S ectio n o f th er oss S ectio n o f th e

Forear morear m



Mus cl es o f th e A bdo min alus cl es o f th e A bdo min al

Wallal l



Mus cl es o f th e Pel vicus cl es o f th e Pel vic

Outletutlet



9-53

Musc les o f Pel vic O utletsusc les o f Pel vic O utlets

and Uro genital D iap hra gmnd Uro genital D iap hra gm



Muscl es Tha t M ove theuscl es Tha t M ove the

Thighhigh



Mus cl es That M ov e th e Legus cl es That M ov e th e Leg




Footo ot



9-57

Musc les of the Th ig h a nd L egusc les of the Th ig h a nd L eg



9-58

Musc les o f th e Th ig h a nd L egusc les o f th e Th ig h a nd L eg



Muscl es of the Th ig h a nduscl es of the Th ig h a nd

Legeg



Cr oss S ectio n o f th e Thighr oss S ectio n o f th e Thigh



Muscl es o f t he L eguscl es o f t he L eg



9-63




• myoglobin, ATP, and creatine

phosphate decline

• by age 80, half of muscle mass

has atrophied

• adipose cells and connective

tissues replace muscle tissue

• exercise helps to maintainmuscle mass and function

Life-Sp an Ch angesife-Sp an Ch anges



Myasthenia Gravis• autoimmune disorder

• receptors for acetylcholine on muscle cells are attacked

• weak and easily fatigued muscles result• difficulty swallowing and chewing

• ventilator needed if respiratory muscles are affected

• treatments include

• drugs that boost acetylcholine• removing thymus gland

• immunosuppressant drugs

• antibodies

Clin ic al App lica tionlin ic al App lica tion

Active vs. Inactive Muscle: Active vs. Inactive Muscle:



Active vs. Inactive Muscle:Muscular AtrophyMuscular Atrophy

Exercise and Diet StimulatesExercise and Diet Stimulates



Exercise and Diet StimulatesMuscle DevelopmentMuscle Development

Arnold Schwarzenegger – BodyArnold Schwarzenegger – Body

Builder Actor and PoliticianBuilder Actor and PoliticianHans and FranzHans and Franz

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