| Muscle fascicle | |
|---|---|
) Structure of a skeletal muscle. (Fascicle labeled at bottom right.) | |
| Details | |
| Part of | Skeletal muscle |
| Identifiers | |
| Latin | fasiculus muscularis |
| TA2 | 2006 |
| TH | H3.03.00.0.00003 |
| Anatomical terminology | |
A muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.[1]
Structure
Myocytes are grouped into muscle fascicles by enveloping perimysium connective tissue.[1] Fascicles are bundled together by epimysium connective tissue.[1] Muscle fascicles typically only contain one type of muscle cell (either type I fibres or type II fibres), but can contain a mixture of both types.[2]
Function
Specialized muscle fibers in the heart that transmit electrical impulses from the atrioventricular node (AV node) to the Purkinje fibers are fascicles, also referred to as bundle branches. These start as a single fascicle of fibers at the AV node called the bundle of His that then splits into three bundle branches: the right fascicular branch, left anterior fascicular branch, and left posterior fascicular branch.
Clinical significance
Myositis may cause thickening of the muscle fascicles.[3] This may be detected with ultrasound scans.[3]
Muscle fascicle structure is a useful diagnostic tool for dermatomyositis. Myocytes towards the edges of the muscle fascicle are typically narrower, while those at the centre of the muscle fascicle are a normal thickness.[4]
Muscle fascicles may be involved in myokymia, although commonly only individual myocytes are involved.[5]
See also
- Connective tissue in skeletal muscle
- Endomysium
- Epimysium
References
- ^ a b c Damjanov, Ivan (2009-01-01), Damjanov, Ivan (ed.), "Chapter 21 - Skeletal Muscles", Pathology Secrets (Third Edition), Philadelphia: Mosby, pp. 434–447, doi:10.1016/b978-0-323-05594-9.00021-0, ISBN 978-0-323-05594-9, retrieved 2020-11-04
- ^ Gandevia, SIMON C.; Burke, DAVID (2004-01-01), Paxinos, GEORGE; Mai, JÜRGEN K. (eds.), "CHAPTER 5 - Peripheral Motor System", The Human Nervous System (Second Edition), San Diego: Academic Press, pp. 113–133, doi:10.1016/b978-012547626-3/50006-5, ISBN 978-0-12-547626-3, retrieved 2020-11-04
- ^ a b Möller, Ingrid; Bong, David; Mendieta, Eugenio de Miguel (2010-01-01), Wakefield, Richard J.; D'Agostino, Maria Antonietta (eds.), "Chapter 19 - Soft Tissue Rheumatism", Essential Applications of Musculoskeletal Ultrasound in Rheumatology, Philadelphia: W.B. Saunders, pp. 219–235, doi:10.1016/b978-1-4377-0127-2.10019-x, ISBN 978-1-4377-0127-2, retrieved 2020-11-04
- ^ Harati, Yadollah; Biliciler, Suur (2010-01-01), Rolak, Loren A. (ed.), "CHAPTER 4 - Myopathies", Neurology Secrets (Fifth Edition), Philadelphia: Mosby, pp. 63–82, doi:10.1016/b978-0-323-05712-7.00004-0, ISBN 978-0-323-05712-7, retrieved 2020-11-13
- ^ Ha, Ainhi D.; Jankovic, Joseph (2011-01-01), Brotchie, Jonathan; Bezard, Erwan; Jenner, Peter (eds.), "An Introduction to Dyskinesia—The Clinical Spectrum", International Review of Neurobiology, Pathophysiology, Pharmacology, and Biochemistry of Dyskinesia, Academic Press, 98: 1–29, doi:10.1016/b978-0-12-381328-2.00001-8, ISBN 9780123813282, PMID 21907081, retrieved 2020-11-13
External links
- Histology image: 77_04 at the University of Oklahoma Health Sciences Center – "Slide 77 skeletal muscle"
- Anatomy Atlases - Microscopic Anatomy, plate 05.83 – "Smooth Muscle"
- Diagram at kctcs.edu