The musculoskeletal system
supports your body, protects your internal organs, and allows for all of
the complex movements necessary for every day motion. Proper functioning
of the musculoskeletal system makes these movements possible and comfortable.
The structures that make up the musculoskeletal system are: bones, muscles,
joints, ligaments, tendons, fascia, and bursae.
Bone -- Bones provide the primary
framework that supports the entire body. Because the bones support
the body, they allow weight bearing and movement. Each bone is made
up of several layers of tissue in which new cells are constantly being
made and old ones re-absorbed. Some bones protect the tissue beneath
them, such as the skull protecting the brain.
Muscle -- There are three
types of muscles: cardiac (striated, involuntary), smooth (non striated,
involuntary), and skeletal (striated, voluntary). The heart is made up of cardiac
muscles which contract spontaneously to pump blood. Smooth muscle
is found in hollow organs, such as the stomach, intestines, and trachea.
Nerves and hormones regulate smooth muscle activity. Skeletal
muscles are attached to bones and require nerves to stimulate contraction.
When the muscles contract, it forces the bones to move.
Joint -- A joint, or articulation,
is the location where two bones come together. Joints keep the bones
in position, while allowing them to move next to each other. The
ends of the bones are covered with cartilage, which provides a cushion
between the two bones. Further cushioning is provided by synovial
fluid that fills a capsule surrounding the ends of the bones. Joints
are described based on the type of movement allowed. For example,
the hip and shoulder make up two ball and socket joints. The elbow
and knee are hinge joints. In the wrist, the bones move along
the surface of other bones making a gliding joint.
Ligament -- Ligaments
are made up of dense fibers and attach one bone to another. They
have no blood supply, so when damaged, they can take a long time to heal.
Tendon -- The fibers that attach
muscles to bones make up the tendons. Tendons have very little blood
supply, so when injured, they require longer to heal.
Fascia -- Fascia is the connective
tissue sitting under the skin and surrounding muscles. The fascia
separates muscles, keeping them apart, while allowing them to glide over
each other.
Bursae -- The bursae are small
sacs of connective tissue located around joints. The synovial fluid
inside these bursae function to prevent friction between the moving parts
of the joint.
