A band


Also found in: Dictionary, Thesaurus, Legal, Financial, Encyclopedia, Wikipedia.

band

 [band]
1. a part, structure, or appliance that binds; for anatomical structures, see frenulum, tenia, trabecula, and vinculum.
2. in dentistry, a thin metal strip fitted around a tooth or its roots.
3. in histology, a zone of a myofibril of striated muscle.
4. in cytogenetics, a segment of a chromosome stained brighter or darker than the adjacent bands; used in identifying the chromosomes and in determining the exact extent of chromosomal abnormalities. Called Q-bands, G-bands, C-bands, T-bands, etc., according to the staining method used. See also layer, stria, and stripe.
A band the dark-staining zone of a sarcomere, whose center is traversed by the H band.
H band a pale zone sometimes seen traversing the center of the A band of a striated myofibril.
I band the band within a striated myofibril, seen as a light region under the light microscope and as a dark region under polarized light.
M band the narrow dark band in the center of the H band.
matrix band a cylindrical metal band with a special clamp or holder (the matrix retainer); it is filled with softened impression compound and seated over a tooth so that the compound flows into the prepared cavity and an impression of the tooth can be obtained. It is also used for placement and contouring of certain restorative materials.
orthodontic band a band fitted over a tooth to anchor an orthodontic fixed appliance.
Z band a thin membrane in a myofibril, seen on longitudinal section as a dark line in the center of the I band; the distance between Z bands delimits the sarcomeres of striated muscle.

A band

in muscle tissue, the area between two I bands of a sarcomere, marked by partial overlapping of actin and myosin filaments and appearing dark. Compare I band.

A band

(band)
Muscle striation containing myosin filaments; appears dark under light microscope and light in polarized light.

A band

The darker of the two alternating stripes seen along muscle fibers (myofibrils) when viewed with a polarization microscope. The A bands are regions in which the thin (actin) filaments overlap the thick (myosin) filaments. The alternating regions, lighter in color, are the I bands and contain only actin fibrils. Synonym: anisotropic band; anisotropic disk
See also: band