Download Skeletal Structures and Functions: Bones and Their Articulations

Skeletal Structures and Functions:
Bones and Their Articulations
Bones
Bones are the primary organs in the skeletal system. Their functions
include:
Protection of vital structures, such as the spinal cord, brain, heart,
and lungs.
• Support of body structures.
• Body locomotion through coordination with the muscular system.
• Hematopoiesis, or generation of blood cells, within the red marrow
spaces of bones.
• Storage and release of the inorganic minerals calcium and
phosphorous, which are needed for functions such as muscle
contraction and neural signal conduction.
It's common to think of the skeletal system as being made up of only
bones, but the skeletal system contains many types of structures. In
addition to localizing blood cell formation and storing calcium, bones
come together at locations called articulations (or joints) to allow for
locomotion and work. In any complex system that moves (such as a
bicycle or car), allowing functional, repetitive motion requires a lot of
control and support.
•
Connective Tissues
In addition to bones, the skeletal system contains other important
connective tissues including: cartilage and ligaments . Tendons ,
technically a structure of the muscular system, is also an important
connective tissue for stabilizing joints and supporting structures.
Cartilage is a firm yet pliable substance that performs a variety of
functions: protection, shape maintenance and support, lubrication, and
shock absorption. Its primary function is to coat the end of the bones
where they articulate with one another, providing a smooth, cushioned
surface. Furthermore, cartilage can serve as a template for bone
formation during development and bone healing (this will be further
discussed in the section about bone ossification).
Ligaments and tendons support articulations and control the muscle
attachment to the bones. Ligaments connect bones to one another and
stabilize articulations. Tendons connect bones to muscles.
The structures of ligaments and tendons are similar, in that both tissues
are made of fibrous proteins aligned in the direction of force. The types
of proteins and differences in stretch and recoil distinguish the
mechanical behavior of ligaments and tendons. Ligaments are stiffer,
but deform more, since they stabilize articulations. Tendons are
wrapped with a continuation of the fascia that surrounds muscle cells to
help transmit and dissipate force.