Muscular
Functions:
There are more that 650 muscles in the Muscular system. So if
you weigh 80 pounds, you have approximately 40 pounds of muscle. But
that is a good thing, since everything you do requires muscles. Muscles can
only pull, so every muscle has a partner to undo what the other muscle did.
Muscles also hold your body in position.
In each muscle, there are strands called muscle fascicles. In each
muscle fascicle, there are even smaller strands called muscle fibers. In each
muscle fiber, there are strands called muscle fibrils. In each muscle fibril,
there are strands called muscle filaments. Muscle filaments slide over each
other when a muscle contracts, and the muscle shortens. The striped
appearance of the filaments is caused by the overlapping of the filaments.
Major parts and organs:
Some of the major parts and organs of the muscular system are
skeletal muscles, smooth muscles, and cardiac muscles. Skeletal
muscles form the body�s fleshy bulk. Skeletal muscles are called voluntary
muscles because they don�t move on their own, you have to tell them to
move. Skeletal muscles pull on bones to cause deliberate movement.
Smooth muscles form layers inside the body�s organs. Smooth muscles are
called involuntary muscles because you don�t have to think about moving
them for them to move. Cardiac muscle is only found in the heart�s walls,
and it never tires.
Interactions with other systems:
The Musculatory system depends on many of the other body
systems. Two of them are the Skeletal and Nervous systems. The
muscles are attached to your bones. The Muscular system supports the
bones. The movement of your muscles is controlled by the Nervous system. The
Nervous system contains specialized nerve cells, called motor neurons, that
stimulate muscle contraction.
Diseases:
Cramps, Muscular Dystrophy, and Myasthenia Gravis are three
conditions that affect the Muscular system. Muscular Dystrophy is a
crippling disease. It gradually wastes the skeletal muscles. One treatment for
this is the use of Prednisone. Myasthenia Gravis is a chronic disease that
is marked by progressive weakness and abnormally rapid fatigue of the
voluntary muscles. The use of drugs is the best treatment for this disease.
Cramps are painful conditions of the muscles in which there is excessive and
prolinged contraction of the muscle fibers due to the exertion, repetitive
motion, or lack of blood flow. A good treatment for cramps is stretching the
muscles.