chapter 10

  1. How many human skeletal muscle are there?
    about 600
  2. Three kinds of muscle tissue
    • 1. skeletal
    • 2. cardiac
    • 3. smooth
  3. Functions of the Muscles
    • Movement
    • Stability-antigravity muscles
    • Control of openings and passageways- sphincter
    • Heat production by skeletal muscles
  4. Connective Tissue of a Muscle
    • Endomysium
    • Perimysium
    • Epimysium
    • Fascia
  5. Endomysium
    thin sleeve of loose connective tissue surrounding each muscle fiber.

    allows room for capilliaries and nerve fibers to reach each muscle fiber
  6. Perimysium
    slightly thicker layer of connective tissue

    Fascicles- bundles of muscle fibers wrapped in perimysium

    carry larger nerves and blood vessels, and stretch receptors
  7. Epimysium
    • fibrous sheath surrounding the entire muscle
    • outer surface grades into the fascia
    • inner surface sends projections between fascicles to form perimysium
  8. Fascia
    sheet of connective tissue that separates neighboring muscles or muscle groups from each other and the subcuyaneous tissue.
  9. Classification of Muscles According to Fascicle Orientation
    • fusiform muscles
    • parallel
    • triangular (convergent)
    • pennate
    • circular (sphincters)
  10. Fusiform Muscles
    thick in middle and tapered at the end

    ex. biceps brachii, gastrocnemius
  11. Parallel Muscle
    have uniform width and parallel fascicles

    can span longer distances than other shapes

    ex. rectus abdominis and zygomaticus major
  12. triangular muscle
    fan-shaped broad at orgin and tapering to a narrow insertion

    ex. pectoralis major, temporalis
  13. pennate muscle
    • fascicles insert obliquely on a tendon (feather shaped)
    • Unipennate, bipennate or multipennate
    • ex. palmar interosseos, rectus femons deltoid
  14. circular muscles (sphincters)
    • rind around body opening
    • orbicularis oculi, urethral and anal sphincters
  15. Muscles Attachments
    • Indirect
    • Direct (fleshy)
  16. Tendons-
    • Indirect Attachment
    • bridge the gap between muscle ends and bony attachment
  17. aponeurosis
    tendon is a broad, flat sheet of tendon
  18. retinaculum
    connective tissue band that tendons from separate muscles pass under
  19. Some skeletal muscle do not insert on bone, but in dermis of the skin muscles of facial expression
  20. Muscle Origins and Insertions
    Origin- bony attachment at stationary end of muscle

    Belly- thicker, middle region of muscle between origin and insertion

    Insertion- bony attachment to mobile end of muscle.
  21. Functional Groups of Muscles
    • action
    • prime mover
    • synergist
    • antagonist
    • fixator
  22. action
    the effects produced by a muscle
  23. prime mover (agonist)
    muscle that produces most of force during a joint action

    ex. brachialis
  24. synergist
    muscle that aids the prime mover

    • stabilizes the nearby joint
    • modifies the direction of movement

    ex. biceps brachii
  25. antagonist
    opposes the prime mover

    • relaxes to give prime mover control over an action
    • preventing excessive movement and injury

    triceps brachii
  26. antagonistic pairs
    muscles that act on opposite sides of a joint
  27. fixator
    muscle that prevents movement of bone

    ex. muscle that holds scapula firmly into place - Rhomboids
  28. Rhombus
    shaped muscles associated with the scapula and are chiefly responsible for it retraction
  29. Intrinsic Muscles
    entirely contained within a region, such as the hand
  30. extrinsic muscles
    act on a designated region, but has its origin elsewhere

    fingers-extrinsic muscles in the forearm
  31. Innervation of a muscle
    refers to the identity of the nerve that stimulates it

    enables the diagnosis of nerve, spinal cord, and brainstorm injuries from their effects on muscle function
  32. spinal nerves
    • arise from the spinal cord
    • emerge through intervertebrial foramina
    • immediately branch into a posterior and anterior ramus
    • innervate muscles below the neck
  33. plexus
    weblike network of spinal nerves adjacent to the verebral column
  34. cranial nerves
    • arise from the base of the brain
    • emerge through skull foramina
    • innervate the muscles of the head and neck
    • numbered I to XII
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chapter 10