What is the definition of A-Band?

A-Band: Refers to the part of the muscle cell that looks darker under a microscope. This area of the cell is darker due to the parallel arrangement of thicker filaments (myosin) and overlap with the thinner filaments (actin).

  • As a muscle contracts, the A-band is where actin and myosin interact.
  1. Saladin, K. (2014). Anatomy & physiology: The unity of form and function. McGraw-Hill Higher Education, New York. ISBN: 9780073403717

Image: Sameerb in English WP, Copyrighted free use, https://commons.wikimedia.org/w/index.php?curid=764619 


Related Terms

  • Actin
  • Myosin
  • Sarcomere
  • Muscle fiber
  • Filament
  • Z-line
  • I-band
  • H zone


  • anisotropic

Related Courses

  • Muscle Cell Structure and Function
  • Muscle Fiber Types
  • Muscle Fiber Dysfunction and Trigger Points