What is Sarcomere in Muscle?
A sarcomere is the fundamental unit of muscle contraction and consists of bundle of thick and thin filaments. It has the following key features:
- Sarcomeres are present in series to form a myofibril and span from Z-line to Z-line. It is only a few micrometers long. Z-lines mark the boundaries of a sarcomere and anchor the thin filaments.
- It consists of overlapping actin and myosin filaments.It is present in a repeating pattern.
- Actin filaments are thin and extend from the Z-line towards the center. Myosin filaments on the other hand, are thicker and are located in the center.
- H- Zone is the central region of a sarcomere where only myosin filaments are present. It shortens during muscle contraction.
- I-band is the region containing only actin filaments, extending from the Z-line towards the center, and shortening during muscle contraction.
- A-band is the central region of the sarcomere where both actin and myosin filaments overlap.
- M-line is present at the center of the A-band that anchors the myosin filaments.
- Muscle contraction occurs as actin and myosin filaments slide past each other, causing the sarcomere to shorten.
- Sarcomeres contract when stimulated by a nerve impulse, leading to the shortening of the muscle fiber and the generation of force.
Also Read: Major Difference Between Actin and Myosin
Sliding Filament Theory
The sliding filament theory explains how muscle fibres contract. The sliding filament theory can be best explained as how muscles contract by the interaction of actin and myosin filaments sliding past each other within muscle cells. The process requires ATP for energy.
The sliding filament theory was proposed in 1954 by Andrew Huxley and Rolf Niedergerke. In this article, we will study the sliding filament theory of muscle contraction notes in detail.
Table of Content
- What is Sliding Filament Theory?
- What is Sarcomere in Muscle?
- Sliding Filament Theory of Muscle Contraction
- Sliding Filament Theory Diagram
- Summary of the Sliding Filament Theory Steps
- How Does Muscle Contraction Occur?
- Importance of Sliding Filament Theory
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