SOLUTIONS TO EXERCISES, LESSON 5
1. Muscle tissues are specialized to produce tension by contraction. In fact, they
function solely by contraction. As a by-product, muscle tissues also produce heat. The
term "contraction" means the production of tension through the interaction of the muscle
2. Myofilaments are long complexes of protein molecules. There are two main types
of myofilaments: actin and myosin. The myosin filaments are thicker and have
appendages known as myosin bridges. The myosin filaments are surrounded by
thinner actin filaments. Great numbers of well-developed mitochondria are found in
3. A popular theory explaining the contraction of striated muscle fibers is the "sliding
filament" theory. This theory emphasized the role of the myosin bridges, which swing
and draw the actin filaments over the myosin filaments.
What is the "all-or-none" phenomenon concerning the contraction of striated muscle
fibers? When stimulated to contract by a nervous impulse, a striated muscle fiber
contracts totally or not at all.
The tension produced by a striated muscle fiber is potentially greatest when the
4. Striated muscle fibers are found in skeletal muscles, branchiomeric muscles,
extraocular muscles, and integumentary muscles. (para 5-7)
5. The individual skeletal muscle is composed primarily of striated muscle fibers and
FCT fibers. White striated muscle fibers are fast. Red striated muscle fibers are slow.
The fast striated muscle fibers can contract rapidly and strongly but for a short time.
The slow striated muscle fibers can contract for a long time. (para 5-8)
6. Muscle soreness is often the result of the tearing of the FCT attachment to the
7. A multipennate muscle is generally much stronger than a ribbon muscle. The
ribbon muscles have a longer distance of contraction than that of the multipennate
8. As a muscle extends beyond its resting length, the tension produced by FCT fibers
becomes greater and greater. Thus, as a whole skeletal muscle lengthens, the tension