Section II. SKELETAL MUSCLES
An organ is a collection of tissues that together perform a particular function.
The individual muscles of the body are individual organs. Their overall function is to
produce effects by the production of tensions. An individual muscle of the body is made
up of muscle tissues, fibrous connective tissues (FCT), and the muscular NAVL.
5-7. KINDS OF MUSCLES WITH STRIATED MUSCLE FIBERS
Several kinds of muscles have striated muscle fibers as their muscle tissue.
These include the:
a. Skeletal Muscles. The skeletal muscles are attached to the bones of the
skeleton. Since they cross joints, they produce motion at these joints.
b. Branchiomeric Muscles. The branchiomeric muscles are those associated
with the jaws, pharynx, palate, and larynx.
c. Extraocular Muscles. The extraocular muscles are within the orbit. They
are attached to and move the eyeball.
d. Integumentary Muscles. The integumentary muscles are developed in
association with the deep surface of the skin (integument proper). A prime example of
the integumentary muscles consists of the facial (mimetic) muscles.
MAKEUP OF AN INDIVIDUAL SKELETAL MUSCLE
The individual skeletal muscle is composed primarily of striated muscle fibers
and FCT fibers.
a. Striated Muscle Fibers. There are two types of striated muscle fibers--fast
(white) and slow (red).
(1) Fast (white). The fast striated muscle fibers can contract rapidly and
strongly but only for a short time.
(2) Slow (red). The slow striated muscle fibers tend to contract more slowly
but for a sustained duration. The red color of slow striated muscle fibers is because of
myoglobin protein. This protein has the capacity to store oxygen within the sarcoplasm.
Thus, oxygen is available for the production of energy during the contraction.