Z line Histology.
(zɛd, U.S. ziː, laɪn)
[Partial tr. G. schicht z z layer (T. W. Engelmann 1873, in Arch. f. die ges. Physiol. VII. 37), f. initial letter of zwischenscheibe intervening disc.]
A transverse dark line in a fibril of striated muscle formed by Krause's membrane (see Krause b); the membrane itself.
| 1916 Jordan & Ferguson Text-bk. Histol. iv. 105 This stripe or accessory disk..bisects the portion of the J disk between the Z line and the succeeding Q disk. 1954 Nature 22 May 976/1 The series elastic component is provided either by the actin filaments themselves, or, more probably, by their mode of attachment to the Z-line. 1979 Sci. Amer. May 94/2 In muscle fibers the actin filaments are anchored to flat protein structures called Z lines, which are emplaced between every two contractile units. |
Also Z band.
| 1950 A. W. Ham Histology xix. 283/1 When a substantial degree of contraction has occurred, an appearance, often referred to as a ‘reversal of striations’, becomes apparent. This is due to the substance of the myofibril on each side of the Z band, which was formerly light, becoming dark, and the dark material of the Q band becoming light. 1964 G. H. Haggis et al. Introd. Molecular Biol. iv. 101 The segment from one Z-band to the next, along a fibril, is termed a sarcomere. 1970 [see Krause b]. |