health occupations muscular system – unit 1. musclelocation function frontalisabove nose &...
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Muscle Location FunctionFrontalis Above nose & eyes Raises eyebrows
Temporalis Temples Closes the jawOrbicularis Occuli Around eye Closes eyeMasseter Jaw Clenches teethOrbicularis Oris Around lips Closes lips, kissesTrapezius Upper back & neck Extends head, shoulderSternocleidomastoid side of neck Turns & flexes headDeltoid Shoulder Abducts arm, injectionPectoralis Upper chest Adducts & flexes armTriceps Upper arm Extends lower armSerratus Ventral lower ribs Moves scapulaAnterior biceps Upper arm Flexes lower armLattisimus dorsi Spine around to chest Extends, adducts arm
Rectus abdominis Ribs to pubis Compresses abdExterior oblique Lower abd/pelvis (lat) Bends/rotates vertebrae
Sartorius Front of thigh Abducts & flexesRectus femoris Front of thigh Extends legVastus lateralis Lateral thigh Extends kneeVastus medialis Medial thigh Extends kneegastrocnemius Back of lower leg Flexes sole of footTibialis anterior Front of lower leg Flexes & inverts foot
Bicep femoralis Back of thigh Flexes knee, lat rotate thigh, extendshipGluteus maximus buttocksExtends thigh, injection
Achilles tendon Back of calf Allows calf to function
Frontalis
SternocleidomastoidTrapezius
DeltoidPectoralisTricepsSerratusBiceps
Latissmus dorsiRectus abdominusExterior oblique
Gluteus maximusSartoriusRectus femoris
Vastus lateralisVastus medialis
Gastrocnemius
Tibialis anterior
Achilles tendon
Muscular System
Made up of over 600 muscles Organs – bundles of muscle fibers held
in place by connective tissue Contraction
– Movement of muscles when stimulated Tonus
– Muscle’s ability to maintain slight & continuous contraction
Muscular System
Types of stimulation– Electrical– Mechanical– Chemical
When not contracted, muscles are FLACCID or soft
Properties of muscles
Excitability– Irritability, ability to respond to a stimulus such as
a nervous impulse Contractility
– Ability to shorten forcefully when stimulated Extensibility
– Ability to be stretched Elasticity
– Ability to recoil to its resting length when relaxed
Functions of muscle
Aids in movement Provides & maintains posture Protects internal organs Provides movement of blood, food, &
wastes through the body Opens & closes body openings Produces heat
Types of muscle tissue
Muscle type Appearance Manner of control
Skeletal Striated Voluntary
Visceral Smooth Involuntary
Cardiac Indistinctly striated
involuntary
Skeletal Muscle
>40% of body weight Increases in size & weight with exercise Decreases in size & weight with inactivity Variety of sizes & shapes due to genetics,
nutrition, & exercise Tendons – attach muscles to bone
– Narrow strips of dense connective tissue– Gastrocnemius
• Calf muscle attaches with the Achilles tendon to the heel
Skeletal Muscle
Fascia – – Tough, sheetlike membrane– Covers & protects tissue
• Deep muscles of back & trunk are surrounded by lumbodorsal fascia
Named by:– Location– Related bones– Shape– Action– Size
Skeletal Muscle
Appearance– Striated under microscope– Made up of bundles of fine fibers– Number of fibers doesn’t increase much
after birth– Muscle mass increases due to increase in
fiber SIZE not number
Actions & Movements of skeletal muscles Adduction – toward midline Abduction – away from midline Flexion – decreasing angle between 2 bones Extension – increasing angle between 2 bones Rotation – turning a part around its own axis Circumduction – moving in a circle @ a joint Pronation – turning hand or foot downward or
backward Supination – turning hand or foot upward or
forward
Sarcomere
Basic unit of muscle fibers causing muscular contraction
Made up of actin & myosin myofibrils Most contract under voluntary control 3 parts to skeletal muscle
– Origin – the end of muscle attaching to less moveable part of bone
– Action or body – thick, middle part of muscle– Insertion – the end of muscle attaching to most
moveable part of bone
Sarcomere (cont)
Movement occurs by pulling bones, working in PAIRS– One muscle contracts– Counteracting muscle relaxes
Prime mover – AGONIST– Pulls to contract muscle
Antagonist muscle –– Relaxes when agonist contracts
Synergists & fixators– Keep muscle & bone stable during movement
Sarcomere (cont)
Atrophy – Shrinking in size & loss of strength of
muscle– Occurs when muscle is not used over time
Contracture– Severe tightening of a flexor muscle– Results in bending of a joint– Foot drop is common
Visceral Muscle
Smooth, NO striations like skeletal muscle Contracts when stimulated Controlled by autonomic nervous system Lines various organs
– Makes up walls of blood vessels– Found in tubes of digestive system– Sphincter muscles (circular)
• Opens & closes pupils• Urinary bladder
Cardiac muscle
Found only in heart Indistinctly striated Involuntary control Has specialized cells that provide a
stimulus for contraction - PACEMAKER
Range of Motion (ROM)
Standards– Move each joint slowly, gently, smoothly– Support each joint during movement– Don’t move joint past its present level of
movement– If pain occurs, stop movement & report– Watch face, especially eyes, for signs of pain– Discuss exercise plan with charge nurse– Perform ROM on one side of body at a time– Move each joint 5 times
ROM Procedure
Wash hands Identify client Explain procedure & ask permission to
perform skill Provide privacy
ROM
Shoulder– Hold wrist & elbow– Flexion & extension– Abduction & adduction– Horizontal abduction & adduction (hand to
opposite shoulder, then back out to shoulder level)
– Rotation of elbow, up & down like hand signal
ROM
Wrist– Hold wrist & fingers– Flexion & extension– Hyperextension of hand– Abduction & adduction of wrist– Tilt Hand towards toes, bring hand, thumb
side up, towards nose
ROM
Fingers/Thumbs– Hold hand– Make fist to flex fingers– Straighten fist by extending fingers– Abduction, adduction of all fingers– Thumb abduction, adduction– Thumb opposition
ROM
Hip & Knee– Hold knee & ankle– Flexion knee & hip, extend knee, return to
resting position– Abduction & adduction– Rotation of leg, inward & outward