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Muscular system

Muscular system. Chapter 8. What do muscles do?. All movements require muscles, which are organs that use chemical energy to contract. Walking, breathing, eating, sneezing, all require muscles Provide muscle t one Propel body fluids and food Generate heart beats Distribute heat

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Muscular system

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  1. Muscular system Chapter 8

  2. What do muscles do? • All movements require muscles, which are organs that use chemical energy to contract. • Walking, breathing, eating, sneezing, all require muscles • Provide muscle tone • Propel body fluids and food • Generate heart beats • Distribute heat • Maintain posture

  3. Types of muscle • Skeletal (majority of this chapter) • Attaches to bone and consciously controlled • Smooth-hollow internal organs, irises, blood vessels • Cardiac-heart

  4. Rules of muscular activity • 1. Muscles get shorter as they contract • 2. Muscles cross at least one joint • 3. Muscles have an origin and insertion • Origin: immovable end of muscle • Insertion: movable end • 4. When a muscle contracts, its insertion is pulled toward the origin.

  5. Interactions of muscles • Skeletal muscles function in groups. • Prime Mover: the muscle doing the majority of the work during a movement • Synergists: helper muscles • Antagonists: opposing muscles

  6. Insertion (moveable end) Origin (immovable end) Muscular movements

  7. Muscular movements • Flexion: angle between joint is decreased

  8. Muscular movements • Extension: angle of joint is increased • Hyperextension: extension beyond normal anatomical position • Abduction: moving a part away from midline • Adduction: moving a part toward midline • Rotation: moving a part around an axis • You will look up the rest of the muscle movements for homework tonight (P. 167-170 in book)

  9. Major skeletal muscles • Named according to: • 1. Size (pectoralis major) • 2. Shape (orbicularis oris) • 3. Location (tibialis anterior) • 4. Movement (extensor digitorum) • 5. Number of attachments (biceps brachii) • About 650 muscles in the human body

  10. Major skeletal muscles

  11. Muscles of facial Expression • Epicranius-raises eyebrow • Orbicularis Oculi-closes eye • Orbicularis Oris-closes and protrudes lips • Buccinator-puckers cheeck • Zygomaticus-raises corner of mouth (Smile) • Platysma-draws angle of mouth downward

  12. Muscles of mastication • (Chewing) • Masseter: elevates mandible • Temporalis: elevates mandible

  13. Muscles that move head • Sternocleidomastoid: pulls head to one side, toward chest, or raises sternum • Splenius capitis: rotates head, bends head to one side, or brings head to upright position • Semispinaliscapitis: extends head, bends head to one side, rotates head

  14. Muscles that move head

  15. Muscles that move arm

  16. Back, Chest Muscles • Trapezius: rotates scapula, raises arm, raises scapula, pulls scapula medially, pulls shoulder down • Deltoid: abducts arm, extends/flexes humerus • LatissimusDorsi: extends/adducts arm, rotates arm inwardly, pulls shoulder down • Rhomboid Major: raises and adducts scapulae • Levator Scapulae: elevates scapulae • Pectoralis Minor: pulls scapula anteriorly and down • PectoralisMajor: pulls arm anteriorly and across chest, rotates humerus, adducts arm

  17. Abdominals • External Oblique • Rectus Abdominus • TransversusAbdominus • Internal Oblique

  18. Muscles that Move Forearm

  19. Move forearm • Biceps Brachii: flexes forearm at elbow and rotates hand laterally • Brachioradialis: flexes forearm at elbow • Triceps Brachii: extends forearm at elbow

  20. Move Hand • Flexor Carpi Radialis: flexes and abducts wrist • Palmaris longus: flexes wrist • Flexor Carpi Ulnaris: flexes and adducts wrist • Extensor Carpi Ulnaris: extends and adducts wrist • Extensor Digitorum: extends fingers • Extensor Carpi radialisbrevis: extends wrist and abducts hand

  21. THigh

  22. Thigh Muscles • Gluteus maximus: extends thigh • Gluteus medius: abducts and rotates thigh medially • Sartorius: flexes leg/thigh, abducts thigh, rotates thigh laterally, rotates leg medially • Semitendinosus: flexes leg, extends thigh • Semimembranosus: flexes leg, extends thigh • Quadriceps femoris (4 parts): extends leg at knee

  23. Muscles that move foot

  24. Muscles that move foot • Tibialis anterior: dorsiflexion and inversion of foot • Extensor digitorumlongus: dorsiflexion and eversion of foot; extension of foot • Gastrocnemius: plantar flexion of foot and flexion of leg at knee • Flexor digitorumlongus: plantar flexion and inversion of foot, flexion of four lateral toes • Tibialis posterior: plantar flexion and inversion of foot

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