muscles

• What is the primary function of skeletal muscle?

  Movement of the skeleton
• What are the three types of muscle?

  Skeletal, cardiac, and smooth
• What are the six main functions of skeletal muscle?

  • Produce skeletal movement
  • Maintain posture & body position
  • Support soft tissues
  • Guard body entrances & exits
  • Maintain body temperature
  • Store nutrients
• What are myocytes?

  Large, tubular cells in skeletal muscle
• What is the significance of the sarcolemma in skeletal muscle cells?

  It is the cell membrane that surrounds myocytes
• What role do T tubules play in muscle contraction?

  They transmit action potentials deep into the muscle fiber
• What are myofibrils composed of?

  Myofilaments, including actin and myosin
• What gives skeletal muscle its striated appearance?

  Sarcomeres, which are repeating units of myofilaments
• What are the components of a sarcomere?

  • Thick filaments (myosin)
  • Thin filaments (actin)
  • Stabilizing proteins
  • Regulatory proteins
  • A bands and I bands
• What happens at the neuromuscular junction?

  The neuron axon terminal meets the muscle fiber to transmit signals
• What is the role of acetylcholine (ACh) at the neuromuscular junction?

  ACh binds to receptors on the muscle fiber to initiate contraction
• What is the sliding filament theory?

  It describes how myofilaments slide past each other during muscle contraction
• What are the phases of a muscle twitch?

  1. Latent period
  2. Contraction phase
  3. Relaxation phase
• What is the difference between isotonic and isometric contractions?

  Isotonic contractions change muscle length, while isometric contractions do not
• How is ATP generated during muscle contraction?

  ATP is generated from phosphocreatine and used to recharge ADP
• What causes muscle fatigue?

  Depletion of metabolic reserves and lactic acid buildup
• What is myasthenia gravis?

  An autoimmune disease affecting the neuromuscular junction
• What are the treatments for myasthenia gravis?

  • AChE inhibitors to increase ACh availability
  • Immunosuppressive drugs
  • Thymectomy in some cases
• What are the key features of skeletal muscle?

  • Multinucleate
  • Striated appearance
  • Contains T tubules
  • Myofibrils made of myofilaments
• What is the role of creatine kinase in muscle energy?

  • Catalyzes the conversion of ADP to ATP using phosphocreatine
  • Helps replenish ATP during muscle contraction
• What is the significance of the sarcoplasmic reticulum in muscle contraction?

  • Stores calcium ions
  • Releases Ca$^{2+}$ ions during contraction
• What is the role of lactic acid in muscle fatigue?

  • Accumulates during anaerobic respiration
  • Lowers pH, affecting muscle function
• What is the function of the Z line in a sarcomere?

  • Defines the boundaries of a sarcomere
  • Anchors thin filaments (actin)
• What is the function of the M line in a sarcomere?

  • Anchors thick filaments (myosin)
  • Located in the center of the sarcomere
• What is the role of the H zone in a sarcomere?

  • Area where only thick filaments (myosin) are present
  • Shortens during muscle contraction
• What is the role of the A band in a sarcomere?

  • Contains both thick (myosin) and thin (actin) filaments
  • Stays the same length during contraction
• What is the role of the I band in a sarcomere?

  • Contains only thin filaments (actin)
  • Shortens during muscle contraction
• What is the role of the Z line in a sarcomere?

  • Defines the boundary of each sarcomere
  • Anchors thin filaments (actin)
• What is the role of the T tubules in muscle contraction?

  • Conducts action potentials deep into the muscle fiber
  • Ensures coordinated contraction of myofibrils
• What is the role of the sarcoplasmic reticulum in muscle contraction?

  • Stores calcium ions
  • Releases Ca$^{2+}$ ions during muscle contraction
• What is the role of the neuromuscular junction in muscle contraction?

  • Site where motor neuron communicates with muscle fiber
  • Releases neurotransmitters to initiate contraction
• What is the role of acetylcholine in muscle contraction?

  • Binds to receptors on muscle fibers
  • Initiates action potential for contraction
• What is the role of calcium ions in muscle contraction?

  • Binds to troponin on thin filaments
  • Triggers conformational change for contraction
• What is the role of ATP in muscle contraction?

  • Provides energy for myosin head movement
  • Required for detachment of myosin from actin
• What is the primary focus of the cardiovascular system?

  The heart is the center of the cardiovascular system.
• What is the role of creatine in muscle energy metabolism?

  • Stores energy in the form of phosphocreatine
  • Recharges ADP to ATP during contraction
• What is the role of lactic acid in muscle metabolism?

  • Byproduct of anaerobic respiration
  • Contributes to muscle fatigue
• What is the role of myasthenia gravis in muscle function?

  • Causes muscle weakness due to impaired AChR
  • Results in decreased muscle contraction efficiency
• What does the term "vascular" refer to?

  "Vascular" refers to blood vessels.
• What is the role of antibodies in myasthenia gravis?

  • Damage ACh receptors on muscle fibers
  • Prevent effective muscle contraction