Muscle fascicle
Template:Short description Script error: No such module "Infobox".Template:Template otherScript error: No such module "Check for unknown parameters".Script error: No such module "Distinguish". A muscle fascicle is a bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.[1]
Structure
Muscle cells 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
In the heart, specialized cardiac muscle cells transmit electrical impulses from the atrioventricular node (AV node) to the Purkinje fibers – fascicles, also referred to as bundle branches.Script error: No such module "Unsubst". 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
References
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
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