MUSCLE and MUSCLE TISSUE

43
MUSCLE MUSCLE and and MUSCLE TISSUE MUSCLE TISSUE Chapter Chapter 11 11

description

MUSCLE and MUSCLE TISSUE. Chapter 11. Muscles are distinguished by their ability to turn ATP (chemical energy) into work (mechanical energy). Muscles do their work in one way – they contract myo – (Greek) “muscle” Sarco – (Greek) “flesh”. Muscle Types. Skeletal - PowerPoint PPT Presentation

Transcript of MUSCLE and MUSCLE TISSUE

Page 1: MUSCLE  and  MUSCLE TISSUE

MUSCLE MUSCLE and and

MUSCLE TISSUEMUSCLE TISSUE

Chapter 11Chapter 11

Page 2: MUSCLE  and  MUSCLE TISSUE

Muscles are Muscles are distinguished by distinguished by their ability to their ability to turn ATP turn ATP (chemical (chemical energy) into work energy) into work (mechanical (mechanical energy)energy)

Muscles do Muscles do their work in their work in one way – they one way – they contractcontract

myomyo – (Greek) – (Greek) “muscle”“muscle”

SarcoSarco – (Greek) – (Greek) “flesh”“flesh”

Page 3: MUSCLE  and  MUSCLE TISSUE

Muscle TypesMuscle TypesSkeletalSkeletal

Attached to and Attached to and covers bonescovers bones

StriationsStriations““voluntary”voluntary”Powerful but Powerful but

tire easilytire easily

Page 4: MUSCLE  and  MUSCLE TISSUE
Page 5: MUSCLE  and  MUSCLE TISSUE

CardiacCardiacIsolated; found only Isolated; found only

in heartin heartStriatedStriated““involuntary”involuntary”Contraction is Contraction is

regular and regular and controlled by neural controlled by neural transmissiontransmission

Page 6: MUSCLE  and  MUSCLE TISSUE
Page 7: MUSCLE  and  MUSCLE TISSUE

VisceralVisceral““Smooth”Smooth”InvoluntaryInvoluntaryNo striatonsNo striatonsContraction is Contraction is slow and slow and sustainedsustained

Page 8: MUSCLE  and  MUSCLE TISSUE
Page 9: MUSCLE  and  MUSCLE TISSUE

FunctionsFunctionsMovementMovement

Locomotion and manipulation Locomotion and manipulation by skeletal muscleby skeletal muscle

Blood coursing – cardiac Blood coursing – cardiac musclemuscle

Propulsion and/or squeezing Propulsion and/or squeezing of substances – smooth of substances – smooth musclemuscle

Page 10: MUSCLE  and  MUSCLE TISSUE

Posture MaintenancePosture MaintenanceSkeletal muscleSkeletal muscleCounteracts gravityCounteracts gravity

Heat GenerationHeat GenerationBy-product of muscle By-product of muscle metabolism and contractile metabolism and contractile activityactivity

Skeletal muscle (40% of Skeletal muscle (40% of body mass) is responsiblebody mass) is responsible

Page 11: MUSCLE  and  MUSCLE TISSUE

PropertiesPropertiesExcitabilityExcitability – ability to receive and – ability to receive and

respond to a stimulus (usually a respond to a stimulus (usually a neurotransmitter)neurotransmitter)

ContractilityContractility – ability to shorten – ability to shorten when stimulatedwhen stimulated

ExtensibilityExtensibility – ability to be – ability to be stretched or extended – to a pointstretched or extended – to a point

ElasticityElasticity – resumes its resting – resumes its resting lengthlength

Page 12: MUSCLE  and  MUSCLE TISSUE

Skeletal Muscle – Gross AnatomySkeletal Muscle – Gross Anatomy

Page 13: MUSCLE  and  MUSCLE TISSUE

EpimysiumEpimysium – connective tissue – connective tissue covering entire muscle covering entire muscle structure structure

FascicleFascicle – bound and separated – bound and separated by by perimysiumperimysium

Muscle fibersMuscle fibers – bound and – bound and separated by separated by endomysiumendomysium

Myofibrils- Myofibrils- composed of composed of myofilamentsmyofilaments

Page 14: MUSCLE  and  MUSCLE TISSUE

Myofilaments Myofilaments - composed of actin - composed of actin and myosin protein fibersand myosin protein fibers

Connective tissue sheaths provide Connective tissue sheaths provide strength to the fragile muscle strength to the fragile muscle fibers; allow a route of entry and fibers; allow a route of entry and exit for blood and nerve fibersexit for blood and nerve fibers

Page 15: MUSCLE  and  MUSCLE TISSUE

MetabolicMetabolic SupplySupplyNerve endingsNerve endingsVascularityVascularity

Page 16: MUSCLE  and  MUSCLE TISSUE

Muscle AttachmentMuscle AttachmentDirect attachmentDirect attachment: :

epimysium to periosteum of epimysium to periosteum of bone.bone.

Indirect attachmentIndirect attachment: : epimysium forms a tendon to epimysium forms a tendon to epimysium of another muscle epimysium of another muscle or periosteum of bone. or periosteum of bone.

Page 17: MUSCLE  and  MUSCLE TISSUE

Fascicle ArrangementFascicle ArrangementPattern influences range of motion Pattern influences range of motion

and powerand powerLong fibers = more range of motionLong fibers = more range of motionPower related to number of muscle Power related to number of muscle

fibersfibersSee page 244 of textSee page 244 of text

Page 18: MUSCLE  and  MUSCLE TISSUE

Microscopic Anatomy of Skeletal Microscopic Anatomy of Skeletal MuscleMuscle

Typically cylindrical, long, Typically cylindrical, long, multinucleatedmultinucleated

Page 19: MUSCLE  and  MUSCLE TISSUE

SarcolemmaSarcolemma (cell (cell membrane) – membrane) – forms elongated forms elongated tubes deep into tubes deep into the cell interior – the cell interior – “T tubules” “T tubules”

SarcoplasmSarcoplasm – with – with stored glycogen stored glycogen and myoglobinand myoglobin

Page 20: MUSCLE  and  MUSCLE TISSUE

Sarcoplasmic Sarcoplasmic ReticulumReticulumSpecialized smooth E.R.Specialized smooth E.R.Connected to Connected to sarcolemmasarcolemma

(plasma membrane); (plasma membrane); provides passage for provides passage for neurotransmitter, glucose, neurotransmitter, glucose, oxygen, etc. into fiberoxygen, etc. into fiber

Regulates intracellular levels Regulates intracellular levels of Ca+ (holds and releases of Ca+ (holds and releases Ca+ on demand)Ca+ on demand)

SarcomeresSarcomeres – smallest contractile – smallest contractile unit of muscle fiber; made of myofibrilsunit of muscle fiber; made of myofibrils

Page 22: MUSCLE  and  MUSCLE TISSUE

Fjkasfjks;dfjkl;sdfjkl;sdfjkl;asfjkl;asdfjklas;dfjkls;adfjsjfk;jsdfkl;jskdlfjkls;fj Kfjsfjkl;asfjkl;sfj

kl;asfjklas;fjkl;asfjkl;asfjkls;adfjksl;dfjksl;dfjksl;dfjksl;dfjksl;fjkls;fjksl;fjksl;dfjksl;fjksl;fjksl;fjksl;fjsklfjkl;sfsj

Page 23: MUSCLE  and  MUSCLE TISSUE

MyofibrilsMyofibrils – 80% of cell volume; – 80% of cell volume; contractile element of cellcontractile element of cellAlternating bands of dark and Alternating bands of dark and

light along length; give myofibril light along length; give myofibril “striated” appearance“striated” appearance

Banding due to 2 distinct protein Banding due to 2 distinct protein filaments (“filaments (“myofilamentsmyofilaments”) within ”) within sarcomeresarcomere

Page 24: MUSCLE  and  MUSCLE TISSUE

Myofilaments

Page 25: MUSCLE  and  MUSCLE TISSUE

Thick filaments – composed Thick filaments – composed of of myosinmyosin protein proteinTail with 2 heads at one end Tail with 2 heads at one end – “cross bridges”– “cross bridges”

Heads contain ATPasesHeads contain ATPasesTails bundled together with Tails bundled together with heads studded outwardheads studded outward

Page 26: MUSCLE  and  MUSCLE TISSUE

Thin filaments – Thin filaments – composed of composed of actinactin protein protein Strands of protein coil Strands of protein coil around each other to around each other to give appearance of give appearance of twisted pearl necklacetwisted pearl necklace

Page 27: MUSCLE  and  MUSCLE TISSUE

Sliding Filament TheorySliding Filament TheoryThin filaments slide past thick Thin filaments slide past thick

filaments causing a myofibril filaments causing a myofibril overlapoverlap

During contraction, thin During contraction, thin filaments penetrate deeperfilaments penetrate deeper

Causes slidingCauses sliding

Page 28: MUSCLE  and  MUSCLE TISSUE

Physiology of Muscle ContractionPhysiology of Muscle ContractionRequires ACh & Ca+Requires ACh & Ca+Stimulation by neurotransmitterStimulation by neurotransmitterACh receptors on sarcolemma ACh receptors on sarcolemma

cause Na+ to flood muscle cellcause Na+ to flood muscle cellNa+ causes sarcoplasmic Na+ causes sarcoplasmic

reticulum to release Ca+reticulum to release Ca+Ca+ binds to Ca+ binds to actinactin = exposing = exposing

actin/myosin binding sitesactin/myosin binding sites

Page 29: MUSCLE  and  MUSCLE TISSUE

Myosin heads bind to Myosin heads bind to exposed actin heads exposed actin heads (exposed in presence of (exposed in presence of Ca+ which moves Ca+ which moves molecules covering actin molecules covering actin binding sites)binding sites)

Page 30: MUSCLE  and  MUSCLE TISSUE

Myosin head binds, forming Myosin head binds, forming cross bridgescross bridges, using energy , using energy from previous ATP from previous ATP hydrolysishydrolysis

Myosin head releases ADP Myosin head releases ADP (energy), thereby pulling (energy), thereby pulling myofilaments = “power myofilaments = “power stroke” stroke”

Page 31: MUSCLE  and  MUSCLE TISSUE

Ca+ is reabsorbed, myosin cross Ca+ is reabsorbed, myosin cross bridges are broken, muscle bridges are broken, muscle relaxes.relaxes.

???What causes rigor mortis??????What causes rigor mortis???

Page 34: MUSCLE  and  MUSCLE TISSUE

Muscle Contraction – Gross LevelMuscle Contraction – Gross LevelMuscles respond in an “all-or-none” Muscles respond in an “all-or-none”

fashionfashion150 muscle fibers/motor nerve, one 150 muscle fibers/motor nerve, one

neuron + all the fibers it innervates = neuron + all the fibers it innervates = one motor unitone motor unit

Page 35: MUSCLE  and  MUSCLE TISSUE

Fibers within a motor unit are Fibers within a motor unit are scattered throughout scattered throughout

Muscles requiring fine motor Muscles requiring fine motor control have fibers of one nerve control have fibers of one nerve close together - fingersclose together - fingers

Page 36: MUSCLE  and  MUSCLE TISSUE

Muscle MechanicsMuscle MechanicsWave Wave

summation – summation – recruit more recruit more cellscells

Tetanus – Tetanus – sustained sustained contractioncontraction

Series of twitches

Summation

Tetanic contraction

Page 37: MUSCLE  and  MUSCLE TISSUE

Isotonic – muscle length variesIsotonic – muscle length variesIsometric – muscle length stays Isometric – muscle length stays

the samethe sameMuscle tone – slight contraction at Muscle tone – slight contraction at

restrest

Page 38: MUSCLE  and  MUSCLE TISSUE

Muscle MetabolismMuscle MetabolismWhen ATP synthesis < ATP use then one When ATP synthesis < ATP use then one

of several things happens because of several things happens because muscles store very little ATP:muscles store very little ATP:ADP + creatine phosphateADP + creatine phosphateAerobic respirationAerobic respirationAnaerobic respirationAnaerobic respiration

Muscle fatigueMuscle fatigueContractures – permanent shorteningContractures – permanent shorteningOxygen debt – lactic acid buildupOxygen debt – lactic acid buildup

Page 39: MUSCLE  and  MUSCLE TISSUE

Animation:Animation:Energy Sources for Energy Sources for Prolonged ExerciseProlonged Exercise

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.

Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.

Page 40: MUSCLE  and  MUSCLE TISSUE

Force, Velocity, & Duration of Force, Velocity, & Duration of ContractionContraction

ForceForceVelocity and duration – dependent Velocity and duration – dependent

upon fiber typesupon fiber typesSlow twitch, fatigue resistantSlow twitch, fatigue resistantFast twitch, fatigue vulnerableFast twitch, fatigue vulnerableFast twitch, fatigue resistantFast twitch, fatigue resistant

Most muscles are a mixture; some Most muscles are a mixture; some areas of body specializeareas of body specialize

Page 41: MUSCLE  and  MUSCLE TISSUE

Slow Twitch Muscle FibersSlow Twitch Muscle Fibers

Slow-twitch fibers Slow-twitch fibers (Type I)(Type I)

Always oxidativeAlways oxidative Resistant to fatigueResistant to fatigue

Red fibersRed fibers Most myoglobinMost myoglobin Good blood supplyGood blood supply Ex. Chicken leg Ex. Chicken leg

marathon runnersmarathon runners

Page 42: MUSCLE  and  MUSCLE TISSUE

Fast Twitch FibersFast Twitch Fibers Fast-twitch glycolytic fibers (Type Fast-twitch glycolytic fibers (Type

IIb)IIb) White fibers (less myoglobin)White fibers (less myoglobin) Poorer blood supplyPoorer blood supply Susceptible to fatigueSusceptible to fatigue Least enduranceLeast endurance Contract rapidlyContract rapidly Ex. Chicken breast; Ex. Chicken breast;

sprinterssprinters

Page 43: MUSCLE  and  MUSCLE TISSUE

DisuseDisuseMuscle atrophy when not used; Muscle atrophy when not used;

this is due either to enforced this is due either to enforced bedrest, immobilization, paralysis, bedrest, immobilization, paralysis, etc.etc.

Muscles atrophy 5% of their Muscles atrophy 5% of their strength/day when immobile; thus strength/day when immobile; thus the reason for “skinny” limbs that the reason for “skinny” limbs that have been in a cast.have been in a cast.