1. Health Occupations
Muscular System – Unit 2

2. Muscular Contraction Occurs through a chain of molecular actions
Sliding Filament Theory
Muscle cells use glycogen to produce energy used to convert ADP to ATP
Stimulus to contract causes the ATP cycle to combine proteins actin & myosin into actomyosin
Calcium is needed for reaction to work

3. Sliding Filament Theory Cont.
Lactic acid is produced from glycogen metabolism and is converted to water and carbon dioxide if oxygen is present
If oxygen is in short supply, lactic acid builds up and soreness occurs
Heat is also produced as a byproduct

4. HEAT Oxygen Metabolism Muscle glycogen CO2 + H20 Lactic acid
If lactic acid builds
Up = soreness
Energy released
Energy
released
ADP – Adenosine
diphosphate
ATP – adenosine
triphosphate
Stimulus to contract-
Energy from ADP/ATP
Cycle, plus Ca++, changes actin +
Myosin = Actomyosin
Energy
released
Phosphate
Calcium
Myosin
Actin
Muscle contraction
Actomyosin

5. Types of Muscle Contraction
Strength depends on the strength of nerve impulses received from the brain
ALL OR NONE LAW OF SKELETAL MUSCLE CONTRACTION
- EACH FIBER CONTRACTS COMPLETELY OR NOT AT ALL!
However, not all muscle contractions are the same

6. Types of Muscle Contraction
Isotonic contraction
Muscle shortening that produces movement
Isometric contraction
Muscle shortening that does NOT produce movement (like pushing against wall)
Tonus
State of partial contraction that maintains posture
Twitch
Quick, jerky contraction of a whole muscle from one stimulus

7. Types of Muscle Contraction
Tetanic contraction
More sustained than twitch, caused by many stimuli in rapid succession
Tetany
Continued contraction of a skeletal muscle
Fibrillation
Uncoordinated contraction of muscle fibers
Convulsions
Contractions of groups of muscles in an abnormal manner
Spasms
Involuntary, sudden, & prolonged contractions

8. Assessment General inspection Systemic movement Reflex Asymmetry
Deformity
Swelling
Bruising
Systemic movement
Assess for weakness
Reflex
Assess neurological functioning

9. Assessment cont Protractor Blood tests Electromyography tests
Measures joint ROM
Blood tests
Measures enzymes indicating muscular damage (esp heart attacks)
Electromyography tests
Tests individual muscles with needles inserted into muscle
Muscle biopsy
Take a slice of muscle to assess for tissue disorders

10. Disorders of muscle system
Muscle cramp
Sudden involuntary contraction of muscle producing pain
Usually in legs or feet
Causes
Exertion
Unknown
Treatment
Stretching
Gentle pressure

11. Muscular dystrophy
Group of genetic diseases involving painless, gradual atrophy of muscle tissue
Mild to severe sx
No cure
Treatment
Meds to slow progression
Braces
Corrective surgery
Gene therapy

12. Fibromyalgia
Group of muscle disorders affecting tendons, ligaments, & fibrous tissues
Pain commonly in neck, shoulders, thorax, lower back, thighs
NO INFLAMMATION
Pain & tenderness after exposure to cold, damp, illness, minor trauma
More common in women
Treatment
Decrease stress
Rest, heat, massage
Therapy to stretch muscles, exercise

13. Gangrene Caused by microorganism
Bacteria enter muscle tissue that has died & destroys surrounding living tissue
Extremities most often affected, but may see it occur in gallbladder or intestines
Treatment
Remove dead tissue
Antibiotics
Meds against toxins

15. Hernia Abnormal protrusion of a body part into another body area
Common – intestine through abd wall
Results from weak abd muscles
Treatment
Bracing
Surgery
Meds

16. Myasthenia gravis
Condition in which nerve impulses are not transmitted normally from the brain to the muscles
Unknown cause
Autoimmune disorder
Muscle weakness in different body areas that eventually become severe
Remission may occur
No cure
Treatment – maintain life support

17. Poliomyelitis Viral infection resulting in paralysis No cure
Vaccination prevents
Treatment
Symptom relief

18. Muscle Sprain
Traumatic injury to tendons, muscles, or ligaments of a joint
Pain & swelling
Treatment
Heat/cold application
Rest
Ultrasound

19. Pes Panus Flat foot Fallen arches Congenital or weak foot muscles
Causes extreme pain
Treatment
Corrective shoes
Massage
Exercise

20. Tetanus Lockjaw Caused by bacteria
Muscle spasms may be severe & can result in death
No cure but vaccine
Treatment
Prevent complications of muscles spasms
Life support

21. Trichinosis Parasitic infection caused by eating undercooked pork
Parasites form cysts in muscle tissues
Diaphragm
Chest muscles
Pain, tenderness, fatigue
Can be fatal if it affects the brain or heart

22. Body Mechanics Careful & efficient use of body Good posture Balance
Using strongest & largest muscles for work
Prevents fatigue, muscle strain, & injury

23. Body Mechanics Posture – body alignment
Lets the body move & function with support & efficiency
Base of support –
Area on which a body rests
Good base of support needed for balance
Feet are base of support when standing

24. Good body mechanics Use strongest & largest muscles whenever possible
Shoulders
Upper arms
Hips
thighs
Bend knees & squat to lift heavy objects
Do not bend from waist
Hold items close to your body & base of support
Avoid unnecessary bending & lifting

25. Good body mechanics Do your work at waist level
Push, slide, or pull heavy objects rather than lifting them
Widen base of support when pushing or pulling
Move front leg forward when pushing
Move rear leg back when pulling
Turn entire body when changing direction of movement

26. Good body mechanics
Avoid sudden or jerky movements, work with smooth & even movements
Get help from co-workers
Don’t lift objects higher than chest level

27. Positioning Proper positioning is important
Promotes comfort & wellbeing
Improves breathing & circulation
Prevents complications
Pressure ulcers
Contractures

28. Fowler’s position HOB 45 – 60 degrees Keep spine straight
Support head & arms with pillows

29. Supine position Back-lying position with flat bed
Head & shoulders supported with pillows
Arms/hands at sides, may support hands on small pillows with palms down

30. Prone position Lying on abd with head turned to one side
Pillow under head, abd, lower legs
Arms flexed at elbow with hands near head
Feet can hang over mattress, then don’t need a pillow under lower legs

31. Lateral or Side-lying position
Pillow under head & neck
Upper leg in front of lower leg & supported with pillows
Small pillow under upper hand & arm
Pillow behind back

32. Sim’s position
Left side-lying position with upper leg sharply flexed so it is not on the lower leg
Lower arm behind patient
Pillows under head & shoulder, upper leg, upper arm & hand