Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
Z line
References
Images
Diagram showing the structure of striated muscle at the myofilament level, with thick myosin filaments, thin actin filaments, crossbridges, Z lines, and one sarcomere labeled. Diagram showing the oblique arrangement of myofilaments in obliquely striated muscle, with thick myosin filaments, thin actin filaments, crossbridges, and angled Z lines labeled. Diagram showing the structure of human striated or skeletal muscle, with labeled cross-sections from whole muscle to fascicle, muscle fiber, myofibril, and sarcomere, highlighting actin and myosin filaments. ultrastructure of a group of myofibrils
Britannica AI Icon

Z line

physiology
Written by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica
Last updated

Quick Summary

Diagram showing the structure of striated muscle at the myofilament level, with thick myosin filaments, thin actin filaments, crossbridges, Z lines, and one sarcomere labeled.
myofilaments in a striated muscle Figure 2: The arrangement of the myofilaments in a striated muscle. The muscle is extended in the upper diagram and contracted in the lower one. The thick filaments are 1.6 micrometres (0.0016 millimetre) long in vertebrate striated muscle but up to six micrometres long in some arthropods.

The Z line is a dark, thin band found in striated muscle fibers. It marks the boundary between adjacent sarcomeres, which are the fundamental units of muscle contraction. Specifically, the Z line serves as the attachment point for actin filaments, a key component of the muscle's contractile machinery. The region between two Z lines constitutes a sarcomere, and the sliding of actin and myosin filaments within these sarcomeres is responsible for muscle shortening and force generation. The Z line's position is crucial for organizing these filaments and ensuring proper muscle function.1234

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
4 Britannica Sources
  1. Z line
  2. muscle - Sliding of filaments
  3. muscle - Molecular mechanisms of contraction
  4. muscle - Cross bridges

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.