Muscle Tissue.pptx

• What is the study of muscle tissue called?

  Myology
• How do muscles provide movement?


  By alternating contraction and relaxation
• What percentage of total adult body weight do muscles make up?


  40-50%
• What are the functions of muscle contraction?


  • Generate force
  • Perform work
  • Produce movement
  • Stabilize body position
  • Regulate organ volume or structure size
  • Generate heat
  • Propel fluids and food matter through various body systems
  • Improve circulation within the extremities
• What are the three types of muscle tissue?

  • Skeletal muscle
  • Cardiac muscle
  • Smooth muscle
• How do the three types of muscle tissue differ?

  In microscopic anatomy, location, and nervous system control
• Where is skeletal muscle typically attached?


  To bones
• What characterizes skeletal muscle?


  It is striated and voluntary
• What is the role of the diaphragm in skeletal muscle control?


  It can be subconsciously controlled
• Where is cardiac muscle found?


  Only in the heart
• What is unique about cardiac muscle contractions?


  They are involuntary and initiated by a natural pacemaker
• What is autorhythmicity in cardiac muscle?


  It refers to electrically active cells that do not require external stimulation
• How can hormones and neurotransmitters affect cardiac muscle?


  They can affect heart rate and contractility
• Where is smooth muscle located?


  In the walls of hollow internal structures
• What characterizes smooth muscle?


  It is non-striated and involuntary
• What is the role of hormones in smooth muscle function?


  They can influence muscle function
• What is electrical excitability in muscle tissue?


  The ability to respond to stimuli by producing action potentials
• What types of stimuli can trigger action potentials in muscle tissue?


  Autorhythmic electrical signals, neurotransmitters, hormones, and pH changes
• What is contractibility in muscle tissue?


  The ability to contract forcefully when stimulated
• What is extensibility in muscle tissue?


  The ability to stretch within limits
• What connective tissue surrounds muscle fibers?


  Connective tissue surrounds and protects muscles
• What is the subcutaneous tissue primarily composed of?


  Adipose tissue
• What are the three layers of connective tissue in muscles?

  • Epimysium: outer layer encircling the entire muscle
  • Perimysium: surrounds groups of muscle fibers
  • Endomysium: separates individual muscle fibers
• How do the connective tissue layers attach skeletal muscle to bone?


  They form tendons and aponeuroses
• What type of neurons stimulate skeletal muscles?

  Somatic motor neurons
• How does blood supply reach muscles?

  Through arteries and veins that run together with nerves
• What is the average length of a muscle fiber?


  10 cm, but may be as long as 30 cm
• How do muscle fibers arise during embryonic development?


  From the fusion of 100+ mesodermal cells called myoblasts
• What is the sarcolemma?


  The plasma membrane of muscle fibers
• What are T-tubules?


  Tubular invaginations of the sarcolemma that tunnel into the muscle fiber
• What is the role of myoglobin in muscle fibers?


  It binds oxygen molecules for ATP production
• What is the function of the sarcoplasmic reticulum?


  To store high concentrations of calcium ions
• What are myofibrils?


  The contractile organelles of the muscle fiber
• What are filaments in muscle fibers?


  Smaller protein structures involved in contraction
• What is the basic functional unit of the myofibril?

  Sarcomere
• What is the sliding filament mechanism?


  Muscle contraction occurs as myosin heads attach to and pull thin filaments
• What is required for the contraction cycle?

  Calcium ions and ATP
• What happens during the power stroke of the contraction cycle?


  The myosin head pivots and pulls the thin filament toward the M line
• What is the role of acetylcholine at the neuromuscular junction?


  It binds to receptors on the motor end plate to create an action potential
• What occurs when acetylcholine is released at the neuromuscular junction?


  It causes action potentials to propagate along the sarcolemma and T tubules