Post on 18-Dec-2015
Muscular SystemMuscular System
Types of MuscleTypes of Muscle SkeletalSkeletal
– StriatedStriated– VoluntaryVoluntary– MultinucleatedMultinucleated
SmoothSmooth– NonstriatedNonstriated– InvoluntaryInvoluntary
CardiacCardiac– StriatedStriated– InvoluntaryInvoluntary– Intercalated disksIntercalated disks
~ 50% of body weightWork in groups to perform a function
General Functions of Muscular General Functions of Muscular SystemSystem
MovementMovement– Skeletal muscle contractions move body Skeletal muscle contractions move body
in whole or partin whole or part Heat ProductionHeat Production
– Muscle cells produce heat via Muscle cells produce heat via catabolism to maintain temperature catabolism to maintain temperature homeostasishomeostasis
PosturePosture– Continued partial contraction of muscle Continued partial contraction of muscle
in order to perform many functionsin order to perform many functions
Characteristics of all MuscleCharacteristics of all Muscle ExcitabilityExcitability
– Respond to stimuliRespond to stimuli Contractility Contractility
– Actively shorten to exert a pullActively shorten to exert a pull– Tension that can be harnessed by CTTension that can be harnessed by CT
ExtensibilityExtensibility– Continue to contract over range of resting lengthsContinue to contract over range of resting lengths– Ex: smooth muscle can be stretched to several times its Ex: smooth muscle can be stretched to several times its
original length and still contract on stimulationoriginal length and still contract on stimulation ElasticityElasticity
– Return to original length after contractionReturn to original length after contraction
-mysium=CT membrane
and tendon sheath
Muscle Fiber ArrangementMuscle Fiber Arrangement
ConvergentParallel Pennate Bipennate Sphincter
Muscle AttachmentMuscle Attachment
Does NOT move when muscle contracts
Does move when
muscle contracts
Naming MusclesNaming Muscles
LocationLocation FunctionFunction ShapeShape Fiber directionFiber direction Number of heads/divisionsNumber of heads/divisions Points of attachmentPoints of attachment Muscle sizeMuscle size
FrontalisFrontalis Frontal boneFrontal bone
FemorisFemoris FemurFemur
GluteusGluteus Posterior of Posterior of hip/thighhip/thigh
OculiOculi EyeEye
OrisOris MouthMouth
RadialisRadialis RadiusRadius
UlnarisUlnaris UlnaUlna
BrachialisBrachialis ArmArm
Location FunctionAbductorAbductor Moves part away from Moves part away from
bodybody
AdductorAdductor Moves part toward bodyMoves part toward body
DepressoDepressorr
Lowers a partLowers a part
ExtensorExtensor Extends a partExtends a part
FlexorFlexor Flexes a partFlexes a part
LevatorLevator Elevates a partElevates a part
RotatorRotator Rotates a partRotates a part
ShapeDeltoidDeltoid Shaped like delta Shaped like delta
∆∆
OrbicularisOrbicularis CircularCircular
PlatyPlaty Flattened; Flattened; platelikeplatelike
QuadratusQuadratus SquareSquare
RhomboideuRhomboideuss
Diamond-shapedDiamond-shaped
TrapeziusTrapezius TrapezoidalTrapezoidal
Fiber Direction
ObliqueOblique Diagonal to midlineDiagonal to midline
RectusRectus Parallel to midlineParallel to midline
SphincterSphincter Circling an openingCircling an opening
TransversuTransversuss
Right angle to Right angle to midlinemidline
BicepBicep Two headsTwo heads
TricepTricep Three headsThree heads
QuadriceQuadricepp
Four headsFour heads
Number of divisions
SizeBrevisBrevis ShortShort
LongusLongus LongLong
MagnusMagnus LargeLarge
MaximusMaximus LargestLargest
MediusMedius Moderately sizedModerately sized
MinimusMinimus SmallerSmaller
Raises eyebrows
Frowning
Blinking
Laughing
Puckering
Whistling, smiling
Mastication
Mastication
Flexes head
Moves head
Moves head
Flexes head
Superficial Back MusclesSuperficial Back Muscles•Large, fan-shaped muscles provide force in a wide range of body positions
-EX: leaning back to straight vertical and all points in between.
Pull the arm down,Stabilize torso during many movements (EX: bench press)
Shrugging, pulling scapulas together and down
Stabilize shoulder joint, pull arm back
Rotator cuffmuscles
Shoulder movement
Trunk Muscles - ThoraxTrunk Muscles - Thorax
Elevate ribs
Trunk MusclesTrunk MusclesAbdomenAbdomen
Flexes trunk
Compresses abdomen
StabilizesLower back
Upper ArmUpper Arm
Extends forearm
Flexes Upper arm
FlexorsFlexors
ExtensorsExtensors
Upper LegUpper Leg
Quadricep Femoris
Deep muscleVastus intermedius
Semimembranosus
Semitendinosus
Biceps femoris
Lower LegLower Leg
Plantar flexion
FootFoot
Anal and Urogenital MusclesAnal and Urogenital Muscles
PosturePosture Good Posture – body alignment that favors Good Posture – body alignment that favors
function with least workfunction with least work– Standing PositionStanding Position
Head and chest held highHead and chest held high Chin, abdomen, buttocks pulled inChin, abdomen, buttocks pulled in Knees slightly bentKnees slightly bent Feet firmly on ground 6 in. apartFeet firmly on ground 6 in. apart
Poor Posture - puts abnormal strain on ligaments Poor Posture - puts abnormal strain on ligaments and bonesand bones
MaintenanceMaintenance– Tonicity (muscle tone): muscles exert a pull against Tonicity (muscle tone): muscles exert a pull against
gravitygravity Continuous and passive partial contraction of musclesContinuous and passive partial contraction of muscles
Classification of Muscle Group Classification of Muscle Group ActionsActions
Agonist (Prime Mover)Agonist (Prime Mover)– Muscle most responsible for movementMuscle most responsible for movement
AntagonistAntagonist– Opposes prime moverOpposes prime mover– Provides precision and control during prime mover Provides precision and control during prime mover
contractioncontraction– Relaxes when prime mover contractsRelaxes when prime mover contracts
SynergistSynergist– Aid prime moverAid prime mover– Contract at same time as prime moverContract at same time as prime mover
FixatorFixator– Joint stabilizerJoint stabilizer– Maintains posture/balance during prime mover contractionMaintains posture/balance during prime mover contraction
LLeevveer r
SSyysstteemmss
P = Force (push or pull) Contracting MuscleF = Fulcrum JointL = Load Weights, etc
1st Class2nd Class
3rd Class
Muscles & AgeMuscles & Age
Infancy & ChildhoodInfancy & Childhood– Muscle coordination and control allows Muscle coordination and control allows
developmental sequences to occurdevelopmental sequences to occur AgingAging
– Muscles degenerate with ageMuscles degenerate with age Replaced with CTReplaced with CT
Muscle fiber membrane
Sarcoplasm
Muscle cell (fiber)cytoplasm
Network of tubules and sacs: pumps calcium ions in from sarcoplasm to store in sacs
Bundle of microfilaments; almost fill sarcoplasm
Basic contractile unit of muscle fiber
Z line Z line
H zone
A bandI band
Length of myosin heads (wide, dark stripes)
Length of actin (thin, light stripes)
Space betweenactin
Allows impulses to travel along sarcolemma deeper into muscle cell (fiber) Allows impulse traveling
down T tubule to stimulate adjacent sacs
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__sarcomere_contraction.html
MyofilamentsMyofilamentsHolds tropomyosin in place Covers active site on actin
Attracted to actin and forms crossbridge
protein molecules
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_atp_and_cross-bridge_movement_during_muscle_contraction.html
ContractionContraction
1. Synaptic vesicle travels down motor neuron and binds to motor endplate2. Acetylcholine released into synaptic cleft3. Ach binds to receptor on sarcolemma4. Impulse travels along sarcolemma and down t-tubules5. Calcium released from sarcoplasmic reticulum6. Calcium binds to troponin causing conformation change7. tropomyosin shifts to expose active site on actin8. myosin heads bind to actin9. actin filaments are pulled past the myosin head; head unattaches and reattaches to a
new site….repeat
Sliding Filament Theory - sliding of thin filaments toward center of each sarcomere shortens the myofibril and muscle fiber.
troponintropomyosin
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__action_potentials_and_muscle_contraction.html
Excitation & ContractionExcitation & Contraction
(neurotransmitter)
Motor endplateSynaptic cleft
Synaptic vesicle
Impulse sent to muscle fiber Muscle fiber creates movement
Neuromuscular junction
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__function_of_the_neuromuscular_junction__quiz_1_.html
Motor UnitMotor Unit
Smaller # fibers – more precise movement
Larger # fibers – more powerful contraction
•Quick jerk due to brief threshold stimulus•One twitch – 1/10 sec•Rarely occur
•Gradual, step-like increase in contraction strength•Series of twitch contractions 1 sec apart•Muscle contracts more forcefully after it has contracted a few times, then when it first contracts•Warm-up before exercise
•Smooth, sustained contractions•Coordinated contractions of different motor units•Multiple twitch waves add together to sustain muscle tension for longer time
•Very short periods of relaxation between peaks of tension
•Twitch waves fused into a single, sustained peak
All or NONE SR releasing Ca+2
Ca+2 bind to troponin; Cross-bridging
TonicityTonicity
Continual, partial contraction of a Continual, partial contraction of a musclemuscle
FlaccidFlaccid– Muscles with less tone than normalMuscles with less tone than normal
SpasticSpastic– Muscles with more tone than normalMuscles with more tone than normal
Length-tension RelationshipLength-tension Relationship
Sarcomere compressed
Muscle can’t develop tension
Optimal length
Strongest maxcontraction possible
Overstretched
Muscle can’t develop tension due to filamentstoo far apart
Energy SourcesEnergy Sources ATPATP
– Hydrolysis into ADP yields energy required for contractionHydrolysis into ADP yields energy required for contraction– ATP binds to myosin head in order to pull actinATP binds to myosin head in order to pull actin– Fibers continually resynthesize ATP from breaking down Fibers continually resynthesize ATP from breaking down
creatine phosphate (requires glucose and oxygen)creatine phosphate (requires glucose and oxygen) Glucose & oxygenGlucose & oxygen
– Hemoglobin transfers OHemoglobin transfers O22 to muscle fiber to muscle fiber
– Fiber stores glucose as glycogenFiber stores glucose as glycogen
– At rest: Excess OAt rest: Excess O22 in sarcoplasm is bound to myoglobin in sarcoplasm is bound to myoglobin temporarilytemporarily
– Exercise: OExercise: O22 concen. Decreases in muscle, so myoglobin concen. Decreases in muscle, so myoglobin resupplies muscle with Oresupplies muscle with O22
RespirationRespiration Aerobic RespirationAerobic Respiration
– Requires ORequires O22
– Produces max amount of energy available from Produces max amount of energy available from each glucose moleculeeach glucose molecule
Anaerobic RespirationAnaerobic Respiration– Occurs when lack of OOccurs when lack of O22 – Forms lactic acidForms lactic acid
During exerciseDuring exercise Muscles “burn”Muscles “burn”
– OO22 debt debt Heavy breathing during exercise in order to process Heavy breathing during exercise in order to process
lactic acidlactic acid
Muscle FatigueMuscle Fatigue
Muscles loses ability to contract due Muscles loses ability to contract due to lack of ATPto lack of ATP
Lactic acid build upLactic acid build up Cramp – muscle contracts Cramp – muscle contracts
spasmodically, but does not relax spasmodically, but does not relax completelycompletely
Most body movements are a result of both types
Change in Muscle SizeChange in Muscle Size
Atrophy – decrease in muscle sizeAtrophy – decrease in muscle size– Bed Rest: lose 1% muscle strength/dayBed Rest: lose 1% muscle strength/day
Hypertrophy – increase in muscle Hypertrophy – increase in muscle sizesize
MyopathiesMyopathies MyalgiaMyalgia - muscle pain due to overstretching/tearing of muscle fibers - muscle pain due to overstretching/tearing of muscle fibers FibromyalgiaFibromyalgia – widespread muscle and CT pain – widespread muscle and CT pain Strain Strain – caused by overexertion/trauma and can lead to muscle tear– caused by overexertion/trauma and can lead to muscle tear MyositisMyositis - any muscle inflammation - any muscle inflammation FibromyositisFibromyositis - tendon inflammation along with myositis - tendon inflammation along with myositis CrampsCramps
– Painful muscle spasms Painful muscle spasms – Due to mild myositis, fibromyositis, irritation, iron, and water imbalanceDue to mild myositis, fibromyositis, irritation, iron, and water imbalance– Charley HorseCharley Horse
Intense muscle spasmsIntense muscle spasms Last few seconds to few hoursLast few seconds to few hours Caused by injury or overuseCaused by injury or overuse
– DehydrationDehydration– Low K+ or Ca+2Low K+ or Ca+2– Nerve irritated Nerve irritated
TreatmentTreatment– Stop activityStop activity– Stretch and massageStretch and massage– Heat to relax muscleHeat to relax muscle– Ice when spasm is overIce when spasm is over
MyopathiesMyopathies ContusionContusion
– Muscle bruise, local internal bleeding and inflammationMuscle bruise, local internal bleeding and inflammation– Crush injury: severe trauma to muscle, releasing fibers into Crush injury: severe trauma to muscle, releasing fibers into
bloodstream (life threatening)bloodstream (life threatening) Poliomyelitis (Poilio)Poliomyelitis (Poilio)
– Viral infection of nerves controlling skeletal movementViral infection of nerves controlling skeletal movement– Causes partial or full paralysis and deathCauses partial or full paralysis and death– Vaccine created in US in 1950s, but not everywhereVaccine created in US in 1950s, but not everywhere
Muscular DystrophyMuscular Dystrophy– Genetic disease caused by muscle atrophyGenetic disease caused by muscle atrophy– Some forms are fatalSome forms are fatal– Most common form is Duchenne Muscular Dystrophy (DMD)Most common form is Duchenne Muscular Dystrophy (DMD)
Myasthenia GravisMyasthenia Gravis– Autoimmune disease that attacks muscle cells at NM junctionAutoimmune disease that attacks muscle cells at NM junction– Muscle weaknessMuscle weakness– Can become a crisis and affect all four limbsCan become a crisis and affect all four limbs– Could die of respiratory failureCould die of respiratory failure
MyopathiesMyopathies HerniasHernias
– ““protrusion”protrusion”– Reducible – can manipulate protruding organ back into abdominal Reducible – can manipulate protruding organ back into abdominal
cavitycavity– Strangulated – blood flow to organ is stopped; obstruction, Strangulated – blood flow to organ is stopped; obstruction,
gangrene, pain. Vomiting, emergency surgerygangrene, pain. Vomiting, emergency surgery– TypesTypes
Inguinal – hernia extends into inguinal canal into scrotum or Inguinal – hernia extends into inguinal canal into scrotum or labia; affects more maleslabia; affects more males
Femoral – affects more women below groin area due to Femoral – affects more women below groin area due to pregnancypregnancy