myofibril

Examples of myofibril in the following topics:

• Skeletal Muscle Fibers

  • Each myocyte can contain many thousands of myofibrils.
  • Each myofibril is surrounded by the sarcoplasmic reticulum, which is closely associated with the transverse tubules.
  • Myofibrils are composed of long myofilaments of actin, myosin, and other associated proteins.
  • Myofibrils are composed of smaller structures called myofilaments.
  • A muscle fiber is composed of many myofibrils, packaged into orderly units.

• Microscopic Anatomy

  • The cardiomyocytes are composed of tubular myofibrils, which are repeating sections of sarcomeres.
  • Together, myosin and actin form myofibrils, the repeating molecular structure of sarcomeres.
  • Myofibril activity is required for muscle contraction on the molecular level.
  • When ATP binds to myosin, it separates from the actin of the myofibril, which causes a contraction.
  • Binding of Acetylcholine at the motor end plate leads to intracellular calcium release and interactions between myofibrils, eliciting contraction.

• Sliding Filament Model of Contraction

  • However, when multiplied by the number of sarcomeres in a myofibril, myofibrils in a myocyte and myocytes in a muscle, the amount of force and movement generated is significant.

• Characteristics of Muscle Tissue

  • Muscle cells, or myocytes, contain myofibrils comprised of actin and myosin myofilaments which slide past each other producing tension that changes the shape of the myocyte.
  • Voluntary refers to whether the muscle is under conscious control, striation refers to the presence of visible banding within myocytes which occurs due to organisation of myofibrils to produce a constant direction of tension.

• Structure and Function of the Muscular System

  • Muscle cells, or myocytes, contain myofibrils comprised of actin and myosin myofilaments which slide past each other producing tension that changes the shape of the myocyte.
  • Voluntary refers to whether the muscle is under conscious control, while striation refers to the presence of visible banding within myocytes caused by the organization of myofibrils to produce constant tension.

• Myocardial Thickness and Function

  • Together, myosin and actin form myofibril filaments, the elongated, contractile threads found in muscle tissue.
  • The tissue structure of cardiac muscle contains sarcomeres that are made of myofibrils with intercalated disks, that contain cardiomyocytes and have many mitocondria.

• Peripheral Motor Endings

  • The binding of acetylcholine at the motor end plate leads to intracellular calcium release and interactions between myofibrils to elicit contraction.

• Benefits of Stretching

  • A study performed by Magid and Law demonstrated that the origin of passive muscle tension (which occurs during stretching) is actually within the myofibrils, not extracellularly as had previously been supposed.