Lec 5

• What are the three types of muscle tissue?

  Cardiac, smooth, and skeletal muscle tissue
• Where is cardiac muscle tissue located?

  In the heart
• Where is smooth muscle tissue located?

  In the walls of visceral organs and blood vessels
• Where is skeletal muscle tissue located?

  In skeletal muscles
• What percentage of total body weight does skeletal muscle tissue make up?

  Approximately 40% to 45%
• How do skeletal and cardiac muscle tissues appear under a microscope?

  Both are striated in appearance
• How does smooth muscle tissue appear under a microscope?

  It is not striated
• What type of control is skeletal muscle under?

  Voluntary control
• What type of control are smooth and cardiac muscle tissues under?

  Not under voluntary control
• How does a typical skeletal muscle attach to bones?

  It attaches onto two bones, crossing the joint between them
• How many attachments does a typical skeletal muscle have?

  Two attachments
• What is muscular fascia also known as?

  Deep fascia
• What happens when a skeletal muscle contracts?

  It creates a pulling force on the bony attachments
• What is the major component of muscular fascia?

  Collagen fibers
• What small component exists in muscular fascia?

  Elastin fibers
• What are the names of the fibrous fascia surrounding muscle fibers?

  Endomysium, perimysium, and epimysium
• What does endomysium surround?

  Each individual muscle fiber
• What does perimysium surround?

  A group of muscle fibers, dividing them into fascicles
• What does epimysium surround?

  The entire muscle
• What do the Greek roots mys, epi, peri, and endo refer to?

  Mys refers to muscle; epi means upon; peri means around; endo means within
• What is the role of fascial attachment?

  To transfer the force of muscle contraction to the bone
• What is irritability in skeletal muscle?

  The ability of the muscle to respond to stimulus
• What is contractility in skeletal muscle?

  The capacity of the muscle to produce tension between its ends
• What is relaxation in skeletal muscle?

  The giving up of tension
• What is distensibility in skeletal muscle?

  The ability of the muscle to be stretched or lengthened up to a certain limit
• What happens if a muscle is stretched beyond its physiological limits?

  The muscle may suffer harm
• What are skeletal muscles considered in the human body?

  The prime movers
• What is elasticity in skeletal muscle?

  The ability of the muscle to recoil to its original length when an outside force is removed
• How many skeletal muscles does a human have?

  640
• What is the range of shapes and sizes of skeletal muscles?

  From the tiny stapedius muscle to the massive gluteus maximus
• How are muscles situated in relation to joints?

  Across joints and attached at two or more points to bony levers
• What are the classifications of muscles based on shape and fascicular architecture?

  • Muscles designed for strength are of pinnate type.
  • Muscles designed for speed have parallel fibers.
• What is the function of skeletal muscles?

  Producing movement, stabilizing joints, giving shape to body segments, maintaining posture, and forming supportive walls
• How are muscles classified according to myoglobin content?

  • Red muscles: contain more red fibers for slow, long-lasting movements.
  • White muscles: contain more white fibers for rapid, short-term movements.
• How are muscles classified according to the level of contractile activity?

  • Tonic muscles (stabilizers): continuous low-level activity for posture.
  • Phasic muscles (mobilizers): rapid activity for changing positions.
• How are muscles classified according to the orientation of the line of pull to the joint structure?

  • Flexors, extensors, abductors, and adductors.
  • The muscle's position relative to the joint determines its function.
• How are muscles classified according to the number of joints they cross?

  • One joint muscle (e.g., vastus medialis).
  • Two joint muscle (e.g., rectus femoris).
  • Multi-joint muscle (e.g., finger flexors).