Intrafusal muscle fiber

Intrafusal muscle fiber
A muscle spindle, with γ motor and Ia sensory fibers
Details
Part ofSkeletal muscle
FunctionProprioception
Identifiers
Latinmyofibra intrafusalis
THH3.03.00.0.00012
Anatomical terms of microanatomy

Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors).[1][2] They detect the amount and rate of change in length of a muscle.[1] They constitute the muscle spindle,[2] and are innervated by both sensory (afferent) and motor (efferent) fibers.[3]

Intrafusal muscle fibers are not to be confused with extrafusal muscle fibers, which contract, generating skeletal movement and are innervated by alpha motor neurons.[4]

  1. ^ a b Casagrand, Janet (2008) Action and Movement: Spinal Control of Motor Units and Spinal Reflexes. University of Colorado, Boulder.
  2. ^ a b Falkel, LORI (January 1, 2007), Cooper, Cynthia (ed.), "Chapter 4 - Tissue-Specific Exercises for the Upper Extremity", Fundamentals of Hand Therapy, Saint Louis: Mosby, pp. 53–72, doi:10.1016/b0-32-303386-5/50007-2, ISBN 978-0-323-03386-2, retrieved December 21, 2020
  3. ^ Burke, David (January 1, 2014), "Fusimotor System", Reference Module in Biomedical Sciences, Elsevier, doi:10.1016/b978-0-12-801238-3.00249-x, ISBN 978-0-12-801238-3, retrieved December 21, 2020
  4. ^ Johns, Paul (January 1, 2014), Johns, Paul (ed.), "Chapter 4 - Sensory and motor pathways", Clinical Neuroscience, Churchill Livingstone, pp. 49–59, doi:10.1016/b978-0-443-10321-6.00004-7, ISBN 978-0-443-10321-6, retrieved December 21, 2020