Health Occupations Muscular System – Unit 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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