BIOL 121 Chapter 10 Notes

Chapter 10

Muscular Tissue


 The three types of muscular tissue

o Skeletal- found in the skeletal

o Cardiac- found in the heart

o Visceral(smooth muscle)- found in various organs

 The functions

o Producing body movements

o Stabilizing body positions

o Storing and mobilizing substance within the body

o Generating heat

 Components

o Elongated cells CT components called muscle fibers

o Subcutaneous layer-

 Separates muscles from skin

 Pathways for nerves

 Enter and exit for blood vessels

o Fascia:

 Dense sheet of CT that lines body wall and limbs

 Supports the muscles and organs

 Holds muscles together

 Allows free movement

,  Muscles surrounded by epimysium

 Fascicles surrounded by perimysium

 Muscle fibers/cells surrounded by endomysium

 Myofibrils- elongated, contractile threads of striated muscles

 Actin (thin) filaments

 Myosin (thick) filaments

 Sarcolemma – plasma membrane of muscle cell

 Transverse (T) tubules – invaginations of sarcolemma, carry AP

throughout cell

 Sarcoplasm – cytoplasm of muscle cell

 Myofibrils- contractile organs of sk. muscle

 Sarcoplasmic reticulum – fluid-filled system of membranous sacs that

store and release Ca2+

 Terminal cisterns – dilated ends of SR

 Myofilaments – smaller proteins w/i myofibrils

 Thin filaments – actin proteins

 Thick filaments – myosin proteins

 Sarcomere – functional, contractile units

 Muscle proteins:

o Contractile: myosin, actin

o Regulatory: troponin, tropomyosin

o Structural: titin, nebulin, alpha-actin