The term Cardiac Muscle is
used inter-changeably with the term "Heart Muscle".
This is the specialized
muscle that forms the walls of the heart.
The Structure of Cardiac Muscle:
Cardiac muscle has many similarities with skeletal
muscle, but also has some special features. Studies using electron microscopes
(more powerful than the more common, and simpler, optical
microscopes)
show that cardiac muscle consists of a network of
branching elongated cells whose
junctions with other cells are marked by irregular transverse bands
called intercalated discs that are located
at the positions of the end-to-end attachments of the cells. Cardiac
cells are joined to each other ionically by gap junctions.
Cardiac
muscle is striated but,
unlike skeletal skeletal (striated), it is made up of a continuous,
morphologically distinct network of branching
and anastomosing cells.
Cardiac muscle (in common with skeletal
muscle), has actin and myosin microfilaments
organized into sarcomeres.
Throughout
life, cardiac muscle contracts about 70 times per
minute
pumping about 5 litres of blood each minute.
See also our definitions
of components
of the heart.
Other types of muscle tissue:
There are three main types of muscle tissue.
They are:
- Skeletal
Muscle - muscles that move bones (under concious control).
- Smooth
Muscle - surrounding organs and other body structures (nor
under concious control).
- Cardiac
Muscle - the specialised muscle found only in the heart.
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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