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Tropomyosin is one of the protein molecules that (together
with myosin,
actin,
and troponin)
forms the cylindrical structures called myofibrils that,
together, form muscle
fibers.
Myofibrils consist of two types of protein filaments, called
thin
filaments, and thick
filaments. Tropomyosin molecules, together with
troponin and actin molecules, form the thin filaments which have a helix
structure - as shown in the diagram below.
Above: Diagram of Tropomyosin molecules within a Thin Filament.
The key function of tropomyosin is to inhibit
muscle contraction by blocking the interaction of actin and myosin (which
is part of the thick filaments), except when influenced by Troponin.
Muscle contraction generally is regulated by the combined actions of
troponin and tropomyosin, which in turn, are controlled by the concentration
of calcium ions in the muscle sarcoplasm.
For further detail about tropomyosin, visit Edinburgh
University's website .
This Section consists of short summaries about the
structures that form the muscles of the body.
This list is not exhaustive but is intended to be appropriate for students
of A-Level Human Biology, ITEC courses in massage and related subjects,
and some other courses in Health Sciences. Visitors
are encouraged to supplement their study by reading many different sources.
For more general information about Muscles see
the pages about:
Anterior
Muscles, Posterior
Muscles, Facial
Muscles, Terminology
about Muscles, and the Structure
of Muscles. |
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