Muscle structure // function

• What are the three main types of muscle fibers?

  Slow twitch, fast-twitch oxidative, fast-twitch glycolytic
• What is the primary function of slow twitch fibers?

  Postural control and slow locomotion
• How do fast-twitch oxidative fibers differ from fast-twitch glycolytic fibers?

  Fast-twitch oxidative are aerobic and fatigue resistant
• What type of activity are fast-twitch glycolytic fibers best suited for?

  Sprinting, leaping, and evasion
• What are the main components of skeletal muscle anatomy?

  • Myofibrils
  • Sarcomere
  • Protein filaments: myosin and actin
  • Troponin and tropomyosin
• What is the role of troponin in muscle contraction?

  It binds with calcium and regulates actin
• What is excitation-contraction coupling?

  The process linking muscle excitation to contraction
• What is the function of the transverse tubule system?

  It facilitates the transmission of action potentials
• What happens during calcium release from the sarcoplasmic reticulum?

  Calcium binds to troponin, initiating contraction
• How does crossbridge cycling contribute to muscle contraction?

  It allows myosin to pull actin, shortening the muscle
• What is the role of calcium reuptake mechanisms in muscle contraction?

  They help relax the muscle after contraction
• What are the energy sources for muscle contraction?

  • Muscle ATP
  • Phosphocreatine
  • Anaerobic glycolysis
  • Oxidative phosphorylation
• Why is lactate produced during high-intensity exercise?

  Oxygen is limited and ATP demand is high
• What is the net gain of ATP from glycolysis using glucose?

  2 ATP
• How much ATP is produced from one molecule of glucose in oxidative phosphorylation?

  Approximately 32 ATP
• What are the types of smooth muscle?

  • Single-unit: GIT, bronchi, bladder, uterus
  • Multi-unit: ciliary muscles, iris muscles, pilomotor muscles
• How do smooth muscle contractions differ from skeletal muscle contractions?

  Calcium ions control crossbridge activity in smooth muscle
• What is the role of calmodulin in smooth muscle contraction?

  It replaces troponin in regulating contraction
• What is the pacemaker function in cardiac muscle?

  • Initiates action potentials
  • Regulates heart rhythm
  • Located in the SA node
• What is calcium-induced calcium release in cardiac muscle?

  Calcium release from the sarcoplasmic reticulum
• Why are muscle fiber types important in different sports?

  They determine performance and endurance levels
• What role do metabolic enzymes play in muscle contraction?

  They facilitate energy production during contraction
• What are the differences between relaxed and contracted smooth muscle?

  Relaxed muscle has less tension than contracted muscle
• How do skeletal muscle fibers differ from smooth muscle fibers?

  Skeletal muscle fibers are striated, smooth are not
• What is the function of the SA node in cardiac muscle?

  It initiates the heart's action potentials
• Troponin binds to actin filaments, inhibiting myosin binding sites when there's no Ca2+ present.
• Smooth Muscle Contractions Involve

  Nerve impulses and hormone release to stimulate the muscle
• Calcium ions in Smooth Muscle Contractions


  Released from sarcoplasmic reticulum, increasing cytosolic calcium concentration
• There are three types of muscle tissue: skeletal, smooth, and cardiac.
• The sarcoplasmic reticulum is the storage site for calcium
• Tropomyosin covers troponin on actin filament, preventing myosin from attaching to it.
• The sliding filament theory states that the interaction between actin and myosin causes the sarcomere to shorten, resulting in muscle contraction.
• When calcium enters the cell, it binds with troponin, causing tropomyosin to move out of the way so that myosin can attach to actin.
• What type of muscle is found in this image?

  Skeletal

  
• What type of muscle is found in this image?

  Smooth muscle

  
• What type of muscle is found in this image?

  Cardiac muscle

  
• Annotate the diagram

  Red - Terminal cisternae

  Pink - Plasmalemma

  Green - Sarcoplasmic reticulum