Muscle is a tissue designed for movement

    Muscular tissue is designed for one thing:  contraction.   Contraction is a type of movement.  Therefore, it depends on the cytoskeleton.

    Here is a little diagram of a muscle contracting and then relaxing.  You will notice that as the muscle contracts, it pulls (via the tendons-- the white material connecting the muscle to the purple line) the purple lines closer.

    Muscles have to be able to both contract and relax in order to be effective.  All of these movements depend on the cytoskeleton within them.   Therefore, you will see that muscles have elaborately fashioned cytoskeletal machinery.

There are three types of muscle tissue:

    All three of these muscular tissues are full of cytoskeletal elements, which I will now refer to as contractile machinery.  They just have differing amounts, slight differences in arrangement, and slight differences in molecular make-up of contractile machinery.  All of these muscle tissue types are well vascularized.

Skeletal Muscle (a.k.a. striated muscle)

    This muscle has the most regular arrangement of contractile machinery and produces the most force.  This is the type of muscle that we use to carry out all of our voluntary movements.

Cardiac Muscle

    This muscle is similar to skeletal muscle... but it doesn't produce quite as much force.  This muscle is only used in our hearts to pump blood through our bodies.

Smooth Muscle

    This muscle produces the least amount of force.  It is used to carry out all of our involuntary movements; for example, when our stomach churns.

© 2006 STCC Foundation Press
written by Dawn A. Tamarkin, Ph.D.