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MUSCULARSYSTEM
HumanAnatomyUnit2
InAnatomyToday
FunctionsMovementsofbonesandsoftbodyparts
Movementsoffluidsthroughatube(blood,digestive)
Functions
Maintainposture Supportsoftorgans
FunctionsControlmovementthroughapassageoropening Controlbodytemperature
MuscleFascia
MuscleTissue
• Connectivetissuelayersarecontinuouswitheachother– Tendon– Periostium– Epimysium– Perimysium– Endomysium
FascicleOrientation5MuscleTypes
• Fusiform• Parallel• Convergent• Pennate• Circular
FusiformMuscles
• Thickinmiddle• Taperedatends• Moderatelystrongcontractions
• Examples:– Bicepsbrachii– Gastrocnemius
ParallelMuscles
• Straplikewithparallelfascicles
• Uniformwidth• Contractmorethanothermuscletypes
• Weakerthanfusiform• Examples:– Rectusabdominis– Sartorius
PennateMuscles• Feather-shaped• Fascicleinsertsintotendonrunningthroughmuscle
• Unipennate– Semimembranosus
• Bipennate– Rectusfemoris
• Multipennate– Deltoid
CircularandConvergentMuscles
• Circular– Sphincters– Ex)Obicularisoris
• Convergent– Fanshaped– Narrowatinsertion– Strong– Ex)Pectoralismajor
Macrostructureofskeletalmuscle
• Origins– attachmentofamuscletoastationarybone
• Insertions– attachmentofamuscletoamovablebone
CharacteristicsofOriginsandInsertions
• Indirectattachments(mostcommon)– Tendons
• cordlikestructuresoffibrous,regularconnectivetissue– Aponeuroses
• awide,thin,tendon
• Directattachments– themusclesurfaceisattacheddirectlytotheperiosteumofbone
NamingMuscles
• Byfiberarrangement• Rectus– Fascicles(fibers)runparalleltothemusclelongitudinalmidlineaxis(LMA)
• Example– Rectusabdominis
NamingMuscles
• Byfiberarrangement• Transverse
– FasciclesareperpendiculartotheLMA
– Transverseabdominis– Transversus costarum
• Oblique– Fasciclesareatanangle
differentthanparallelorperpendicular
– Internal/externaloblique
NamingMuscles
• Bylocation• Relativelocation– Tibialis anterior– Vastus lateralis– Serratus dorsalis– Scalenius dorsalis
• Profundus– adeepmuscle– Flexordigitorumprofundus
NamingMuscles
• Bysize–maximus–minimus–medius–brevis– longus–magnus
NamingMuscles
• Bythenumberoforigins–biceps–triceps–quadriceps
NamingMuscles
• Byshape• Deltoideus– Triangular– Attachedatside
• Trapezius– Quadrilateral– 2sidesthatareparallel
• Rhomboideus– parallelogram
NamingMuscles
• Byoriginandinsertion– Sternocleidomastoid– Sternohyoid
NamingMuscles
• Byaction• flexorpolliceslongus(pollux=thumb)
• pronatorteres(teres=round)
• extensordigitorum
FunctionalGroupsofMuscles
1. Primemovers(agonists)2. Synergists3. Antagonists4. Fixators
PrimeMovers
• Muscleproducesmostofforceduringmovementacrossaparticularjoint
• 11types– Flexor Abductor– Extensor Adductor– Levator Depressor– Supinator Pronator– Rotator Sphincter– Tensor
TypesofMuscleFibers
• Classifiedbasedonthespeedofcontraction1. Slow(TypeI,SO)2. Intermediate(TypeIIA,FO:fastoxidative)3. Fast(TypeIIB,FG:fastglycolytic)
• Othercharacteristics– Primarysourceoffuel– Myoglobincontent– Diameteroffiber– Bloodsupply– Timetofatigue
SlowTwitchFibersTypeI:SOFibers
• Smalldiameter• Fatigueresistant– Verygoodbloodsupply–Myoglobin(redmeat)–Manymitochondria
• Takealongtimetocontractafterstimulation• Developlesstension• Primarilyaerobicmetabolism– Lipids,carbohydrates,aminoacids
IntermediateTwitchFibersTypeIIA:FOFibers
• Fasttwitch• Intermediate– Diameter– Fatigueresistance
• Bloodsupply• Numberofmitochondria• Myoglobincontent
– Tension
• Primarilyaerobicmetabolism– Carbohydrates– High[glycolyticenzymes]insarcoplasm
FastTwitchFibersTypeII,FGFibers
• Largediameter• Fatiguequickly– Poorbloodsupply– Nomyoglobin(whitemeat)– Fewmitochondria
• Generatesalotoftension(Force)• Primarilyanaerobicmetabolism– Creatine phosphate– High[glycolyticenzymes]insarcoplasm
FiberTypeDistribution