1. Muscular System
Why do people lift weights? Why do we exercise our muscles?
Over 600 muscles make up muscular system
45% of total body weight of an adult
Made up of bundles of muscle fibers (long slender cells) held together by connective tissue

2. Key Word Parts My/o-, mys-, and sarco- refer to muscle
Spas- (draw, pull), tens- (stretch), -plegia (paralysis), therap- (treatment), therm- (heat), dynam- (power)
Myo-, mys-, and sarco- refer to muscle
Spas- (draw, pull), tens- (stretch), -plegia (paralysis), therap- (treatment), therm- (heat), dynam- (power

3. Functions The human body has more than 600 muscles
The functions of the muscular system
Movement
Maintain Posture
Stabilization of joints
Generation of heat
Protection of some internal organs
Movement:
locomotion/manipulation, - (muscle action such as walking aids the flow of blood through veins as it returns to the heart)
heartbeat,
moving substances through hollow organs (e.g., food thru the digestive system; fluid through the ducts and tubes associated with othe body systems (i.e., circulatory/lymphatic)
Posture maintenance
Stabilization of joints
Generation of heat – muscle movement generates 85% of body heat
Protection of some internal organs

4. Structures Muscle Fibers -(mean thread like) are long, slender cells
Fascia - Tough, sheet or band of fibrous connective tissue that covers, supports and separates muscle
Tendons - Narrow, band of non-elastic, dense, fibrous connective tissue that attaches a muscle to a bone
Aponeurosis- broad, flat sheet of fibrous connective tissue that is similar to a tendon; however an aponeurosis attaches a muscle to bone OR to other tissues
Over 600 muscles 45% of total body weight of an adult
These muscles are made up of fibers, covered with fascia, and attached to bones by tendons
Fibers – (mean thread like) are long, slender cells
Each muscle is held together by connective tissue and enclosed In a fibrous sheath
Fascia
Tough, sheet or band of fibrous connective tissue that covers, supports and separates muscle (the muscle membrane)
Example: lumbodorsal fascia which surround the deep muscles of the trunk and back
Tendon
Narrow, band of nonelastic, dense, fibrous connective tissue that attaches a muscle to a bone
Examples: Achilles tendon which attaches the gastrocnemius muscle on the calf of the leg to the heel bone
Aponeurosis: broad, flat sheet of fibrous connective tissue that is similar to a tendon; however an aponeurosis attaches a muscle to bone OR to other tissues
Example: Abdominal aponeurosis

5. Types of Muscles
Cardiac
Visceral/Smooth
Skeletal

6. Cardiac Form walls of heart Contract to circulate blood
Striated (banded)
Involuntary
Efferent nerves control rate of contraction
Afferent nerves concerned with sensations
Contract at steady rate except for brief bursts of rapid rate, automaticity
Cardiac
Form walls of heart
Contract to circulate blood
Striated (banded) with lots of mitochondria
Involuntary: function without conscious thought or control (autonomic nervous system control)
Efferent (motor) nerves control rate of contraction based on needs of the body
Afferent (sensation) nerves concerned with sensations of pain, spasm, and stretch
Contract at steady rate except for brief bursts of rapid rate, automaticity

7. Visceral/smooth Found in the internal organs of the body
Walls of hollow, visceral organs
No striations = smooth
Involuntary
Efferent (motor) neurons less important
Afferent nerves concerned with sensations of pain, spasm, and stretch
Steady constant contractions, automaticity
Found in the internal organs of the body such as the digestive system, respiratory system, blood vessels, and eyes
Form the Walls of hollow, visceral organs
No striations = smooth
Involuntary: function without conscious thought or control (autonomic nervous system control)
Efferent (motor) neurons less important
Afferent nerves concerned with sensations of pain, spasm, and stretch
Steady constant contractions, automaticity

8. Skeletal Attaches to and covers bony skeleton
Longest fibers of all muscle cells
Striated
Voluntary (central and peripheral nervous system control)
Efferent nerve fibers from brain and spinal cord send impulses for contraction
Afferent nerve fibers from muscle send message to CNS to inform brain of the degree of contraction
Skeletal
40% of body
Attaches to and cover bony skeleton
Longest fibers of all muscle cells
Striated (have dark and light bands that produce striped appearance)
Voluntary: person has control over their action (central and peripheral nervous system control)
Efferent nerve fibers from brain and spinal cord send impulses for contraction
Afferent nerve fibers from muscle send message to CNS to inform brain of the degree of contraction
Contract rapidly, tire easily, tremendous power, adaptable
Cause body movement

9. Properties Excitability: ability to receive & respond to stimulus
Contractility: ability to shorten forcibly
Extensibility: ability to be stretched
Elasticity: ability to resume resting length (of muscle fiber) after being stretched
Automaticity: ability of muscle to contract without a nerve supply

10. Contractility
When muscle fibers are stimulated by nerves they contract (become short and thick) which causes movement
Contraction depends on myofilaments: actin and myosin
When muscle fibers are stimulated by nerves they contract (become short and thick) which causes movement
Contraction involves protein filaments: actin and myosin
When one muscle of a pair (antagonistic pair) contracts the other relaxes

11. Muscle Contraction
Isotonic contraction is muscle shortening that produces movement
Muscle tone or tonus is a state of partial contraction that maintains a person’s posture
Isometric contraction does not cause muscle shortening or movement
A twitch is a quick, jerky contraction of a whole muscle from one stimulus
Muscle Tone
Steady partial contraction present at all times
State of tension when awake
State of readiness to act; enables muscles for immediate response
Does not produce active movement
Keeps muscles firm healthy
Stabilizes joints
Maintains posture

12. Muscle Contraction (continued)
Tetanic contraction is more sustained than a twitch and is caused by many stimuli in rapid succession
Fibrillation is uncoordinated contraction of muscle fibers
Convulsions are contractions of groups of muscles in an abnormal manner
Spasms are involuntary, sudden, and prolonged contractions

13. All or None Response
Once the muscle fiber has been stimulated to contract, the muscle fiber will contract to its fullest extent
Each muscle is served by at least one motor nerve, which contains hundreds of neuromuscular junctions with each single muscle fiber
Motor neuron and all the muscle fibers that it supplies is called a motor unit
When a motor neuron fires, all the muscle fibers that it innervates respond by contracting
Average 150 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 movements
All or None Response
Once the muscle fiber has been stimulated to contract, the muscle fiber will contract to its fullest extent
Each muscle is served by at least one motor nerve, which contains hundreds of neuromuscular junctions with each single muscle fiber
Motor neuron and all the muscle fibers that it supplies is called a motor unit
When a motor neuron fires, all the muscle fibers that it innervates respond by contracting
Average 150 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 movements

14. Loss of muscle tone
When muscles are not used for a long period of time: atrophy, waste away (degeneration and loss of mass)
Complete immobilization - strength decreases 5% per day; paralysis = atrophy to ¼ initial size; eventually muscle tissue replaced by fibrous connective tissue
Lack of use can result in contracture
Severe tightening of a flexor muscle
Results in bending of a joint
Loss of muscle tone
Can occur in severe illness such as paralysis, palsy
When muscles are not used for a long period of time: atrophy, waste away (degeneration and loss of mass)
Complete immobilization of muscle (complete bed rest or loss of neural stimulation or in a cast): strength decreases 5% per day; paralysis = atrophy to ¼ initial size; muscle tissue replaced by fibrous connective tissue - muscle rehabilitation impossible; delay with electrical stimulation
Lack of use can result in contracture (permanent contraction of muscle due to spasm or paralysis)
Severe tightening of a flexor muscle
Results in bending of a joint
When no ATP available, state of continuous contraction results because crossbridges are unable to detach
Foot drop = common
Fingers, wrists and knees as well as other joints can be affected

15. Muscle fatigue Muscle unable to contract Tension drops to zero
Inability to generate enough ATP to power the contractile process
Relative deficit of ATP NOT total absence
Excessive accumulation of lactic acid and ionic imbalances
Muscle fatigue
Muscle unable to contract
Tension drops to zero
Inability to generate enough ATP to power the contractile process
Relative deficit of ATP NOT total absence
Excessive accumulation of lactic acid and ionic imbalances

16. Other Conditions Spasm: sudden involuntary contraction of muscle
Clonic: alternating spasm with relaxation
Tonic: sustained
Tetanus: smooth sustained contraction
Tetany: result of low calcium; increases excitability of neurons; loss of sensation, muscles twitching, convulsions; untreated - spasms of larynx, respiratory paralysis, death
Spasm: sudden involuntary contraction of muscle
Clonic: alternating spasm with relaxation
Tonic: sustained
Tetanus: smooth sustained contraction
Tetany: result of low calcium; increases excitability of neurons; loss of sensation, muscles twitching, convulsions; untreated - spasms of larynx, respiratory paralysis, death

17. Interactions of Skeletal Muscles
Prime Mover/Agonist
Provides major force for producing a specific movement
Initiates movement
Example: biceps brachii - elbow flexion
Antagonist
Oppose or reverse a particular movement
Example: triceps brachii - elbow extension
Synergist
Aid agonists by promotion of same movement or by reducing undesirable/unnecessary movements
Example: muscles which help make fist without bending wrist
Fixator
Synergists which immobilize a bone or a muscle origin
Example: muscles to stabilize scapula
Interactions of Skeletal Muscles – muscles are made of antagonistic pairs – (work opposite each other). In the pair, one muscle produces movement in one way and the other muscle produces movement in the opposite direction
Muscles do not act independently
Prime Mover/Agonist
Provides major force for producing a specific movement
Initiates movement
Example: biceps brachii - elbow flexion
Antagonist
Oppose or reverse a particular movement
Example: triceps brachii - elbow extension
Synergist
Aid agonists by promotion of same movement or by reducing undesirable/unnecessary movements
Example: muscles which help make fist without bending wrist
Fixator
Synergists which immobilize a bone or a muscle origin
Example: muscles to stabilize scapula

18. Actions or Movements of Skeletal Muscles
Goniometry: measurement of joint movement
Adduction: moving a body part toward the midline
Abduction: moving a body part away from the midline
Flexion: decreasing the angle at a joint
Extension: increasing the angle at a joint
Hyperextension: increases the angle beyond the anatomical position
Circumduction: the distal end of an extremity inscribes a circle while the shaft inscribes a cone
Actions or Movements of Skeletal Muscles
Goniometry: measurement of joint movement
Adduction: moving a body part toward the midline
Abduction: moving a body part away from the midline
Flexion: decreasing the angle at a joint
Extension: increasing the angle at a joint
Hyperextension: increases the angle beyond the anatomical position
Circumduction: the distal end of an extremity inscribes a circle while the shaft inscribes a cone

19. Actions or Movements of Skeletal Muscles
Rotation: revolving a part about the longitudinal axis
Internal: move toward the midline or medially
External: move away from the midline or laterally
Supination: turn the palm upward; “what’s up?”
Pronation: turn the palm downward
Inversion: turn the plantar surface away from the midline
Plantar flexion (extension): move the sole of the foot downward as in standing on the toes
Dorsiflexion: move the sole of the foot upward
Range of Motion – change in joint position produced by the muscles
Rotation: revolving a part about the longitudinal axis
Internal: move toward the midline or medially
External: move away from the midline or laterally
Supination: turn the palm upward; “what’s up?”
Pronation: turn the palm downward
Inversion: turn the plantar surface away from the midline
Plantar flexion (extension): move the sole of the foot downward as in standing on the toes
Dorsiflexion: move the sole of the foot upward

20. Figure 14-5 Basic Types of Muscle Movement

21. Muscle Nomenclature
Location i.e. vastus lateral and vastus medialis; external and internal oblique, pectoralis
Origin and insertion i.e. brachioradialis, occipitofrontal
Function/Action i.e. ulnar flexor (flexes wrist), extensor capri muscles (extension motions of the wrists)
Muscle Nomenclature – named for their:
Location i.e. vastus lateral (toward the side) and vastus medialis (toward the midline); external (near the surface) and internal (deeper) oblique, pectoralis
Origin and insertion (origin is the place where the muscle begins- the fixed attachment and insertion is the place where the muscle ends (inserts) – the moveable end or the portion farthest from the midline of the body, i.e. occipitofrontal
Number of heads i.e. biceps, triceps
Function i.e. ulnar flexor (flexes wrist), extensor capri muscles (extension motions of the wrists)

22. Muscle Nomenclature
Number of heads/divisions forming them i.e. biceps, triceps
Size i.e. gluteus maximus
Shape i.e.deltoid
Fiber direction i.e. rectus abdominus (straight muscle of abdomen), orbicularis oris (circular around mouth)
Size i.e. gluteus maximus (largest of the buttock)
Shape i.e.deltoid – shaped like an inverted triangle
Orientation of bundles of muscle fibers i.e. rectus abdominus (straight muscle of abdomen), orbicularis oris (circular around mouth)

23. Adjectives to describe muscles
bi-, tri-, quadri- : 2, 3, 4
Externus: exterior
Gracilis: slender
Latissimus: wide
Longissimus: long
Longus: long
Medius: intermediate
Adjectives to describe muscles
bi-, tri-, quadri- : 2, 3, 4
Externus: exterior
Gracilis: slender
Latissimus: wide
Longissimus: long
Longus: long
Medius: intermediate
Orbicularis: around
Quadratus: square
Rectus: straight
Rhomboideus: diamond shaped
Scalenes: irregular triangle
Teres: round
Transverse: crosswise
Vastus: great

24. Adjectives to describe muscles
Orbicularis: around
Quadratus: square
Rectus: straight
Rhomboideus: diamond shaped
Scalenes: irregular triangle
Teres: round
Transverse: crosswise
Vastus: great

25. Medical Specialties Orthopedic Surgeon Rheumatologist Neurologist
Sports Medicine
Physical Therapist
Chiropractor = manipulative treatmetn of disorders originating from misalignment of the spine
Orthotics = braces or splints to align, support, prevent or correct deformities or to improve the function of movement
Osteopathic Physician – DO – specializes in treating health problems by manipulation.
Orthopedic Surgeon = tx injuries and disorders involving the bones, joints, muscles and tendons
Podiatrist = dx and tx of the foot
Rheumatologist = tx disorders that involve the inflammation of connective tissues including muscles
Neurologist = tx the cause of paralysis and similar muscular disorders in which there is a loss of function
Sports medicine -= treats sports related injuries
Physical Therapy =

26. Assessment Techniques
Reflex tests
Joint motion
Blood tests
Electromyography tests
Muscle biopsy
Reflex tests- DTR with a reflex hammer
Joint motion - ROM testing
Blood tests
Electromyography tests – also known as nerve conduction studies – tests and record neuromuscular activity by the electric stimulation of nerve fibers to and from the muscle
Muscle biopsy

27. Treatment Procedures of the Muscular System
Medications –
Anti-inflammatory
antispasmodics (anticholinergics)
Muscle relaxants
Physical Therapy
ROM
ADLs

28. Treatment Procedures of the Muscular System
Fascia (sheet or band of connective fibrous connective tissue that covers, supports, and seperates muscles)
Fasciotomy
Facioplasty
Muscles
Myectomy
Mypoplasty
Myorrhaphy
Fascia (sheet or band of connective fibrous connective tissue that covers, supports, and seperates muscles)
Fasciotomy – otomy – surgical incision
Facioplasty - plasty = surgical repair
Muscles
Myectomy= surgical removal
Mypoplasty= surgical repair
Myorrhaphy = to suture a muscle wound

29. Treatment Procedures of the Muscular System
Tendon
Carpal tunnel release
Tenectomy
Tenodesis
Tenolysis
Tenonectomy
Tenotomy
Tenoplasty
Tenorrhaphy
Carpal tunnel release – cutting of the carpal ligament to relieve nerve pressure
Tenectomy – surgical removal of a lesion from a tendon
Tenodesis –to suture the end of a tendon to bone (desis = to tie together/bind)
Tenolysis – to free a tendon from adhesionsl (lysis = to set free)
Tenonectomy= surgical removal of part of a tendon for the purpose of shortening
Tenotomy = also known as tendotomy = surgical division of a tendonfor relief of a deformaty caused by abnormal sortening
Tenoplasty = surgical repair
Tenorrhaphy = suturing of a divided tendon

30. Proud of your Muscles?