330 likes | 514 Views
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
E N D
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
Oxygen Metabolism Muscle glycogen CO2 + H20 Lactic acid HEAT 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 • Asymmetry • Deformity • Swelling • Bruising • Systemic movement • Assess for weakness • Reflex • Assess neurological functioning
Assessment cont • Protractor • 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