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The Sarcoplasmic Reticulum is a network of membrane enclosed
tubules similar to
smooth
endoplasmic reticulum that extends throughout the sarcoplasm of muscle
fibres.
Sarcoplasmic Reticulum surrounds
each myofibril and
is physically separated from the sarcolemma.
Structure:
Sarcoplasmic Reticulum is
widers at its two
ends, which form terminal
sacs, called cisternae. A functional unit is a triad, which consists
of two cisternae of adjacent sarcoplasmic reticula and
one transverse
tubule in between. The distance between
the terminal cisternae and
the transervse tubule is 10-15 nm.
Functions:
The functions of the sarcoplasmic reticulum within muscle tissue
include:
- Uptake of calcium
from
the sarcoplasm, and
- Releasing calcium into the sarcoplasm to
initiate muscle contraction and the converse during
relaxation.
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.
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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