7 Anat 35 Muscle Tissue - Mt. SAC Faculty Directoryfaculty.mtsac.edu/mpresch/35_lecture_files_unit_2/7 An… ·  · 2017-02-27Muscle Tissue •Connective tissue layers are continuous

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