The Muscle System
The Muscle System
A chickens muscle system is comprised of 3 types of muscles. These are the smooth muscles, cardiac muscles, and skeletal muscles. The smooth muscles are found in the blood vessels, intestines and gizzard. The cardiac muscles comprise the muscles of the heart. The skeletal muscles are the muscles that shape the bird and are responsible for voluntary movement. The skeletal muscles are the edible muscles on a carcass.
Diagram 7 shows the muscle structure of a chicken
Muscles are structured from special muscle cells in the form of fibres that have the ability to contract or shorten. When they relax the muscle lengthens.
There are three main types of muscles found in any animal body. These are:
Muscle contractions are the result of a stimulus passing into the muscle fibers. This stimulus causes the myofibril segments to shorten because actin filaments slide across the myosin filaments. Much of the energy taken from digested feed is used in muscle contractions, particularly calcium.
There are white and red types of skeletal muscle fibers found in birds and all muscles have some white fibers and some red fibers. However, the proportion varies and some muscles are predominantly white and others predominantly red or dark. White fibers lack a compound called myoglobin, but store more glycogen and have a fast contraction of short duration. They have little staying power. The breast muscles of fowls, the muscles of flight, are predominantly white fibers and fowls have very poor flying ability. They fly very short distances with a very rapid wing movement. Red fibers have myoglobin and other cellular structures for continuous production of energy for contraction. These fibers have a slow contraction of long duration. The flight muscles of flying birds consist mainly of red fibers.
The next page will discuss the reproductive system.
Diagram 7 shows the muscle structure of a chicken
Muscles are structured from special muscle cells in the form of fibres that have the ability to contract or shorten. When they relax the muscle lengthens.
There are three main types of muscles found in any animal body. These are:
- Involuntary muscles found in the walls of the alimentary canal, blood vessels, air passages and other tubular structures. These muscles are beyond the control of the will and are called involuntary muscles. The fibers of these muscles do not carry transverse striation or stripes and are therefore said to be ‘unstriped’ or ‘unstriated’.
- Cardiac muscle of the heart. This too is involuntary muscle but is striated and is structured differently to other muscle. It is nucleated, contains many Purkinje Fibers and forms a syncytium with many nuclei but no differentiation of the protoplasm into cells.
- The striated or striped, voluntary muscles of the body that move the various parts of the skeleton or appendages. These consist of very minute thread-like muscle fibers in bundles enclosed by sheaths of fibrous tissue.
Muscle contractions are the result of a stimulus passing into the muscle fibers. This stimulus causes the myofibril segments to shorten because actin filaments slide across the myosin filaments. Much of the energy taken from digested feed is used in muscle contractions, particularly calcium.
There are white and red types of skeletal muscle fibers found in birds and all muscles have some white fibers and some red fibers. However, the proportion varies and some muscles are predominantly white and others predominantly red or dark. White fibers lack a compound called myoglobin, but store more glycogen and have a fast contraction of short duration. They have little staying power. The breast muscles of fowls, the muscles of flight, are predominantly white fibers and fowls have very poor flying ability. They fly very short distances with a very rapid wing movement. Red fibers have myoglobin and other cellular structures for continuous production of energy for contraction. These fibers have a slow contraction of long duration. The flight muscles of flying birds consist mainly of red fibers.
The next page will discuss the reproductive system.
- Next page: The Reproductive System
- Previous page: The Skeletal System
