Dictionary > Z disc

Z disc

noun, plural: Z discs
The region or line formed in the sarcomere into which the thin filaments are inserted
The sarcomere, the contractile unit of a myofibril, consists of a highly organized assembly of filaments. It is the smallest functional structures and molecules essential for muscle contraction. The two main proteins in a sarcomere are actin and myosin. The actin forms the thin filament whereas the myosin forms the thick filament. The thin and the thick filaments are arranged in a way that they overlap partially enabling them to slide past each other during contraction. The sarcomere is delimited by two Z discs (also called Z lines, Z bands, or intermediate discs). The Z in Z disc stands for the German Zwischenscheibe.
When viewed under the microscope, the Z disc appears as the darkly staining band that bisects the I (isotropic) band of a striated muscle (i.e. the region surrounding the Z disc and the zone of actin filaments not superimposed by myosin filaments). The Z disc is where the actin filaments attach to and thereby serves as the anchoring point of actin filaments in a sarcomere.

  • intermediate disk (disc)
  • Z line
  • Z band

See also:

  • sarcomere
  • actin filament
  • Titin
  • N line

    You will also like...

    Human gastrointestinal tract
    Human Biology – Food and Digestion

    This tutorial recognizes the importance of food as a source of energy that will fuel many biological processes. A good d..

    Control of body movement
    Control of Body Movement

    Some of the body movements can be controlled at will, others cannot. The body has a motor program, which is the pattern ..

    Birth Control and Contraception
    Birth Control and Contraception

    Different pregnancy and birth control and contraception strategies are described. Read this tutorial to learn each of th..

    Direct and indirect physiologic effects of growth hormone
    Animal Growth Hormones

    Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..

    An artistic depiction of a human embryo
    Growth and Development of a Human Baby

    Upon fertilization, a zygote forms and develops into an embryo. This tutorial elaborates on the growth and development f..

    Golgi apparatus (3-D illustration)
    Role of Golgi Apparatus & Endoplasmic Reticulum in Protein Synthesis

    The endoplasmic reticulum and Golgi apparatus are the organelles involved in the translation step of protein synthesis a..