Science: Muscles

  1. Terminology:
    • Flexion-decreases the angle between bones
    • Extension-increases the angle between bones
    • Abduction-moving away from the midline
    • Adduction-moving toward the midline
    • Rotator-produces turning or rotation
    • Levator-produces upward upward movement
    • Depressor-produces downward movement
    • Sphincter-decreases the size of an opening
    • Tendon-connects muscle to bone
    • Muscle-contractual tissue that produces movement across a joint
    • Myofibril-a contractual fiber made up of actin & myosin-yo-filament
    • Sarcomere-the functional unit of the Myofibril
    • Actin Filament-the moving filament of the Myofibril
    • Myosin Filament-the stationary filament of the Myofibril
    • Origin-the muscle attachment to the stationary bone of a joint
    • Insertion-the muscle attachment to the moving bone of a joint
  2. Types of Muscle Contraction:
    • Isometric-the muscle contracts with no joint movement
    • Isotonic-the muscle contracts producing movement at the joint
    • Tonic-the muscle partially contracts producing firm muscle with no joint movement
  3. Types of Muscles:
    • Skeletal Muscle-strait
    • Visceral Muscle-smooth
    • Cardiac Muscle-strait
  4. Muscle Contraction:
    Muscles contract when a motor neuron stimulates a muscle fiber causing the action myofilament to slide over the myosin myofilament. This action shortens and thickens the muscle causing joint movement.
  5. Muscle Fatigues:
    When muscles loss all there sugar and oxygen, they are not able to continue there action. This is fatigue.
  6. Muscles & Nerves:
    Nerve endings are attached to muscle fibers which stimulate muscle contractions at impulse from the brain spinal cord.
  7. 25 Muscles:
    • Epicranius-raises eyebrows
    • Sternocleidomastoid-flexes neck & rotates head
    • Trapezius-raises and lowers shoulders
    • Latissimus Dorsi-adducts arms
    • Forearm Extensors-extends hand
    • Gluteus Maximus-extends thigh
    • Semitendinosis-extends thigh & flexes leg
    • Biceps Femoris-extends thigh & flexes leg
    • Gastrocnemius-extends foot & flexes leg
    • Soleus-plantar flexes foot
    • Deltoid-abducts arms
    • Triceps Brachii-extends forearm
    • Pectoralis Major-adducts arms
    • Serratus Anterur-pulls scapula down and forward
    • External Oblique-rotates and compresses obdomen
    • Rectus Abdominuis-compresses abdomen and flexes trunk
    • Rectus Femoris-flexes thigh & extends leg
    • Vastus Lateralis-extends leg
    • Vastus Medialis-extends leg
    • Tibialis Anterior-dorsiflexes foot
    • Biceps Brachii-flexes forearm
    • Brachioradialis-flexes wrist & rotates arm
    • Forearms Flexors-flexes hand
    • Sartorius-abducts and rotates thigh
    • Pectoralis Minor-pulls shoulders down & forward
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Science: Muscles
all about muscles