Muscular

• What are the characteristics of cardiac muscle?

  • Found only in the heart
  • Involuntary
  • Does not fatigue
• What are the characteristics of smooth muscle?

  • Found in the digestive system and blood vessels
  • Involuntary
  • Involved in vasodilation
• What are the characteristics of skeletal muscle?

  • Voluntary
  • Moves limbs by pulling bones
  • Uses contraction
  • Subject to fatigue
  • Strong
• Describe the process of nerve impulse control in skeletal muscles.

  1. Nerve impulse sent from brain as action potential
  2. Signal reaches neuromuscular junction
  3. Neurotransmitter acetylcholine moves across synaptic cleft
  4. Acetylcholine binds to muscle fiber, initiating the sliding filament theory
• What are the roles of the agonist, antagonist, synergist, and stabilizer in muscle action?

  • Agonist: Muscle under the most tension
  • Antagonist: Controls speed of agonist
  • Synergist: Supports and assists the agonist
  • Stabilizer: Holds isometrically to anchor the position
• What are the layers of a muscle and their functions?

  • Epimysium: Layer holding the whole muscle
  • Perimysium: Layer that holds fascicles
  • Endomysium: Layer that holds each fiber
  • Myofibril: Thinner section that fills a fiber
• What are the roles of sensory and motor neurons in the muscular system?

  • Sensory neurons: Send signals to the brain when sensing is needed
  • Motor neurons: Send signals to muscles to initiate movement
• What changes occur in a sarcomere during muscle contraction?

  • A band width remains the same
  • H band and Z line close up
  • Actin and Myosin filaments interact
• Name some muscles in the upper body.

  • Pectorals
  • Trapezius
  • Abdominals
  • Obliques
  • Rhomboids
  • Latissimus Dorsi
  • Transverse Abdominis
  • Deltoid
  • Biceps & Triceps
  • Wrist flexors/extensors
• What are the three types of muscle fibers and their characteristics?

  • Type 1: slow twitch, low force, high endurance, used in marathon running
  • Type IIa: intermediate twitch, medium force, utilizes oxygen and glucose, used in 400-800m runs
  • Type IIx: fast twitch, high force, uses glucose, short duration, used in explosive activities like tennis volleys
• What are the steps in the sliding filament theory?

  1. Calcium enters cytoplasm from sarcoplasmic reticulum
  2. Tropomyosin changes conformation
  3. Myosin binding sites on actin are exposed
  4. Myosin head attaches to actin (cross-bridge)
  5. ATPase breaks down ATP
  6. Contraction occurs
  7. Calcium is removed from troponin
• What are the different types of muscle contractions?

  • Concentric: Shortening, pulls limbs closer together
  • Eccentric: Lengthening, lowers against gravity, under tension
  • Isometric: Fixed length, under tension
• Name some muscles in the lower body.

  • Iliopsoas
  • Glutes
  • Quads: vastus femoris, vastus lateralis, vastus medialis, vastus intermedialis
  • Hamstrings: biceps femoris, semitendinosus, semismembranosus
  • Anterior Tibialis
  • Soleus
  • Gastrocnemius