Key Word PartsKey Word Parts My/o-, mys-, and sarco- refer to My/o-, mys-, and sarco- refer to
musclemuscle Spas- (draw, pull), tens- (stretch), Spas- (draw, pull), tens- (stretch),
-plegia (paralysis), therap- -plegia (paralysis), therap- (treatment), therm- (heat), (treatment), therm- (heat), dynam- (power) dynam- (power)
FunctionsFunctions
The human body has more than 600 The human body has more than 600 muscles muscles
The functions of the muscular systemThe functions of the muscular system
MovementMovement
Maintain PostureMaintain Posture
Stabilization of joints Stabilization of joints
Generation of heat Generation of heat
Protection of some internal organs Protection of some internal organs
Structures Structures Muscle Fibers -(mean thread like) are long, Muscle Fibers -(mean thread like) are long, slender cellsslender cellsFascia - Tough, sheet or band of fibrous Fascia - Tough, sheet or band of fibrous connective tissue that covers, supports and connective tissue that covers, supports and separates muscle separates muscle Tendons - Narrow, band of non-elastic, Tendons - Narrow, band of non-elastic, dense, fibrous connective tissue that dense, fibrous connective tissue that attaches a muscle to a bone attaches a muscle to a bone Aponeurosis- broad, flat sheet of fibrous Aponeurosis- broad, flat sheet of fibrous connective tissue that is similar to a tendon; connective tissue that is similar to a tendon; however an aponeurosis attaches a muscle however an aponeurosis attaches a muscle to bone OR to other tissuesto bone OR to other tissues
CardiacCardiac
Form walls of heart Form walls of heart Contract to circulate blood Contract to circulate blood Striated (banded) Striated (banded) InvoluntaryInvoluntaryEfferent nerves control rate of Efferent nerves control rate of contraction contraction Afferent nerves concerned with Afferent nerves concerned with sensations sensations Contract at steady rate except for Contract at steady rate except for brief bursts of rapid rate, brief bursts of rapid rate, automaticity automaticity
Visceral/smoothVisceral/smooth
Found in the internal organs of the Found in the internal organs of the bodybodyWalls of hollow, visceral organs Walls of hollow, visceral organs No striations = smooth No striations = smooth InvoluntaryInvoluntaryEfferent (motor) neurons less Efferent (motor) neurons less important important Afferent nerves concerned with Afferent nerves concerned with sensations of pain, spasm, and stretch sensations of pain, spasm, and stretch Steady constant contractions, Steady constant contractions, automaticity automaticity
Skeletal Skeletal
Attaches to and covers bony skeleton Attaches to and covers bony skeleton
Longest fibers of all muscle cells Longest fibers of all muscle cells
Striated Striated
Voluntary (central and peripheral nervous Voluntary (central and peripheral nervous system control) system control)
Efferent nerve fibers from brain and spinal Efferent nerve fibers from brain and spinal cord send impulses for contraction cord send impulses for contraction
Afferent nerve fibers from muscle send Afferent nerve fibers from muscle send message to CNS to inform brain of the message to CNS to inform brain of the degree of contraction degree of contraction
PropertiesPropertiesExcitability: ability to Excitability: ability to receive & respond to receive & respond to stimulusstimulus
Contractility: ability to Contractility: ability to shorten forciblyshorten forcibly
Extensibility: ability to be Extensibility: ability to be stretched stretched
Elasticity: ability to Elasticity: ability to resume resting length (of resume resting length (of muscle fiber) after being muscle fiber) after being stretched stretched
Automaticity: ability of Automaticity: ability of muscle to contract without muscle to contract without a nerve supplya nerve supply
ContractilityContractility When muscle When muscle
fibers are fibers are stimulated by stimulated by nerves they nerves they contract (become contract (become short and thick) short and thick) which causes which causes movementmovement
Contraction Contraction depends on depends on myofilaments: myofilaments: actin and myosin actin and myosin
Muscle ContractionMuscle Contraction
Isotonic contraction is muscle shortening Isotonic contraction is muscle shortening that produces movementthat produces movement
Muscle tone or tonus is a state of partial Muscle tone or tonus is a state of partial contraction that maintains a person’s contraction that maintains a person’s postureposture
Isometric contraction does not cause Isometric contraction does not cause muscle shortening or movementmuscle shortening or movement
A twitch is a quick, jerky contraction of a A twitch is a quick, jerky contraction of a whole muscle from one stimuluswhole muscle from one stimulus
Muscle Contraction Muscle Contraction (continued)(continued)
Tetanic contraction is more sustained than Tetanic contraction is more sustained than a twitch and is caused by many stimuli in a twitch and is caused by many stimuli in rapid successionrapid successionFibrillation is uncoordinated contraction of Fibrillation is uncoordinated contraction of muscle fibersmuscle fibersConvulsions are contractions of groups of Convulsions are contractions of groups of muscles in an abnormal mannermuscles in an abnormal mannerSpasmsSpasms are involuntary, sudden, and are involuntary, sudden, and prolonged contractions prolonged contractions
All or None ResponseAll or None ResponseOnce the muscle fiber has been stimulated to contract, the Once the muscle fiber has been stimulated to contract, the muscle fiber will contract to its fullest extent muscle fiber will contract to its fullest extent
Each muscle is served by at least one motor nerve, which Each muscle is served by at least one motor nerve, which contains hundreds of neuromuscular junctions with each contains hundreds of neuromuscular junctions with each single muscle fiber single muscle fiber
Motor neuron and all the muscle fibers that it supplies is Motor neuron and all the muscle fibers that it supplies is called a motor unit called a motor unit
When a motor neuron fires, all the muscle fibers that it When a motor neuron fires, all the muscle fibers that it innervates respond by contracting innervates respond by contracting
Average 150 muscle fibers per motor unit Average 150 muscle fibers per motor unit
Average 4 to several hundred muscle fibers per motor unit Average 4 to several hundred muscle fibers per motor unit for fine motor control i.e. controlling fingers and eye for fine motor control i.e. controlling fingers and eye movements movements
Loss of muscle tone Loss of muscle tone
When muscles are not used for a long When muscles are not used for a long period of time: atrophy, waste away period of time: atrophy, waste away (degeneration and loss of mass) (degeneration and loss of mass)
Complete immobilization - strength Complete immobilization - strength decreases 5% per day; paralysis = decreases 5% per day; paralysis = atrophy to ¼ initial size; eventually atrophy to ¼ initial size; eventually muscle tissue replaced by fibrous muscle tissue replaced by fibrous connective tissueconnective tissue
Lack of use can result in contractureLack of use can result in contractureSevere tightening of a flexor muscle Severe tightening of a flexor muscle Results in bending of a joint Results in bending of a joint
Muscle fatigue Muscle fatigue
– Muscle unable to contract Muscle unable to contract – Tension drops to zero Tension drops to zero – Inability to generate enough Inability to generate enough
ATP to power the contractile ATP to power the contractile process process
– Relative deficit of ATP NOT Relative deficit of ATP NOT total absence total absence
– Excessive accumulation of Excessive accumulation of lactic acid and ionic lactic acid and ionic imbalances imbalances
Other ConditionsOther ConditionsSpasm: sudden involuntary Spasm: sudden involuntary contraction of muscle contraction of muscle
Clonic: alternating spasm with Clonic: alternating spasm with relaxation relaxation
Tonic: sustained Tonic: sustained
Tetanus: smooth sustained Tetanus: smooth sustained contraction contraction
Tetany: result of low calcium; Tetany: result of low calcium; increases excitability of neurons; loss increases excitability of neurons; loss of sensation, muscles twitching, of sensation, muscles twitching, convulsions; untreated - spasms of convulsions; untreated - spasms of larynx, respiratory paralysis, death larynx, respiratory paralysis, death
Interactions of Skeletal MusclesInteractions of Skeletal Muscles– Prime Mover/Agonist Prime Mover/Agonist
Provides major force for producing a specific Provides major force for producing a specific movement movement Initiates movement Initiates movement Example: biceps brachii - elbow flexion Example: biceps brachii - elbow flexion
– Antagonist Antagonist Oppose or reverse a particular movement Oppose or reverse a particular movement Example: triceps brachii - elbow extension Example: triceps brachii - elbow extension
– Synergist Synergist Aid agonists by promotion of same movement or by Aid agonists by promotion of same movement or by reducing undesirable/unnecessary movements reducing undesirable/unnecessary movements Example: muscles which help make fist without Example: muscles which help make fist without bending wrist bending wrist
– Fixator Fixator Synergists which immobilize a bone or a muscle origin Synergists which immobilize a bone or a muscle origin Example: muscles to stabilize scapula Example: muscles to stabilize scapula
Actions or Movements of Skeletal Actions or Movements of Skeletal MusclesMuscles
– Goniometry: measurement of joint movement Goniometry: measurement of joint movement – Adduction: moving a body part toward the Adduction: moving a body part toward the
midline midline – Abduction: moving a body part away from the Abduction: moving a body part away from the
midline midline – Flexion: decreasing the angle at a joint Flexion: decreasing the angle at a joint – Extension: increasing the angle at a joint Extension: increasing the angle at a joint – Hyperextension: increases the angle beyond Hyperextension: increases the angle beyond
the anatomical position the anatomical position – Circumduction: the distal end of an extremity Circumduction: the distal end of an extremity
inscribes a circle while the shaft inscribes a inscribes a circle while the shaft inscribes a cone cone
Actions or Movements of Skeletal Actions or Movements of Skeletal MusclesMuscles
– Rotation: revolving a part about the longitudinal axis Rotation: revolving a part about the longitudinal axis Internal: move toward the midline or medially Internal: move toward the midline or medially External: move away from the midline or laterally External: move away from the midline or laterally
– Supination: turn the palm upward; “what’s up?” Supination: turn the palm upward; “what’s up?” – Pronation: turn the palm downward Pronation: turn the palm downward – Inversion: turn the plantar surface away from the Inversion: turn the plantar surface away from the
midline midline – Plantar flexion (extension): move the sole of the foot Plantar flexion (extension): move the sole of the foot
downward as in standing on the toes downward as in standing on the toes – Dorsiflexion: move the sole of the foot upward Dorsiflexion: move the sole of the foot upward – Range of Motion – change in joint position produced by Range of Motion – change in joint position produced by
the musclesthe muscles
Muscle NomenclatureMuscle NomenclatureLocationLocation i.e. vastus i.e. vastus lateral and vastus lateral and vastus medialis; external medialis; external and internal oblique, and internal oblique, pectoralis pectoralis Origin and Origin and insertioninsertion i.e. i.e. brachioradialis, brachioradialis, occipitofrontal occipitofrontal Function/ActionFunction/Action i.e. i.e. ulnar flexor (flexes ulnar flexor (flexes wrist), extensor capri wrist), extensor capri muscles (extension muscles (extension motions of the wrists) motions of the wrists)
Muscle NomenclatureMuscle Nomenclature
Number of heads/divisions Number of heads/divisions forming themforming them i.e. biceps, triceps i.e. biceps, triceps
SizeSize i.e. gluteus maximus i.e. gluteus maximus
ShapeShape i.e.deltoid i.e.deltoid
Fiber directionFiber direction i.e. rectus i.e. rectus abdominus (straight muscle of abdominus (straight muscle of abdomen), orbicularis oris (circular abdomen), orbicularis oris (circular around mouth) around mouth)
Adjectives to describe musclesAdjectives to describe muscles
bi-, tri-, quadri- : bi-, tri-, quadri- : 2, 3, 4 2, 3, 4 Externus: Externus: exterior exterior Gracilis: slender Gracilis: slender Latissimus: Latissimus: wide wide Longissimus: Longissimus: long long Longus: long Longus: long Medius: Medius: intermediate intermediate
Adjectives to describe musclesAdjectives to describe musclesOrbicularis: around Orbicularis: around Quadratus: square Quadratus: square Rectus: straight Rectus: straight Rhomboideus: diamond shaped Rhomboideus: diamond shaped Scalenes: irregular triangle Scalenes: irregular triangle Teres: round Teres: round Transverse: crosswise Transverse: crosswise Vastus: great Vastus: great
Medical SpecialtiesMedical Specialties
Orthopedic SurgeonOrthopedic Surgeon
RheumatologistRheumatologist
NeurologistNeurologist
Sports MedicineSports Medicine
Physical TherapistPhysical Therapist
Assessment TechniquesAssessment Techniques
Reflex testsReflex tests
Joint motionJoint motion
Blood testsBlood tests
Electromyography testsElectromyography tests
Muscle biopsyMuscle biopsy
Treatment Procedures of the Treatment Procedures of the Muscular SystemMuscular System
Medications – Medications – – Anti-inflammatoryAnti-inflammatory– antispasmodics (anticholinergics)antispasmodics (anticholinergics)– Muscle relaxantsMuscle relaxants
Physical TherapyPhysical Therapy– ROMROM– ADLsADLs
Treatment Procedures of the Treatment Procedures of the Muscular SystemMuscular System
Fascia (sheet or band of connective fibrous Fascia (sheet or band of connective fibrous connective tissue that covers, supports, connective tissue that covers, supports, and seperates muscles)and seperates muscles)– FasciotomyFasciotomy– FacioplastyFacioplasty
MusclesMuscles– MyectomyMyectomy– MypoplastyMypoplasty– MyorrhaphyMyorrhaphy
Treatment Procedures of the Treatment Procedures of the Muscular SystemMuscular System
TendonTendon– Carpal tunnel releaseCarpal tunnel release– TenectomyTenectomy– TenodesisTenodesis– TenolysisTenolysis– TenonectomyTenonectomy– TenotomyTenotomy– TenoplastyTenoplasty– TenorrhaphyTenorrhaphy