Overview of bone structure, long bone.
can be classif
according to their shape.
than they are wide and consist oF a long shaFt (
) and two ends (
are roughly cube shaped, such
as wrist and ankle bones. Bone also can be classif
based on gross appearance and bone
oF a long bone is composed primarily oF
and an inner medullary cavity, which is f
oF long bones are composed mainly oF
, and the articular surFaces are cov-
ered by articular cartilage, providing a smooth joint surFace For articulation with the next bone. The
is a transitional
zone between the diaphysis and epiphysis; it represents the level that cancellous bone ends and the bone marrow cavity begins.
The external surFaces oF compact bone are covered by
, a thick layer oF dense connective tissue, which contains
, a thin layer oF connective tissue with a single layer oF osteoprogenitor cells and osteoblasts, Forms a boundary
between the bone and the medullary cavity (this layer may be continuous with the trabeculae oF the cancellous bone). The general
structure oF compact bone includes (1) the
, a canal surrounded by layers oF concentric lamellae; (2)
lamellae layers in between the osteons; (3)
outer circumferential lamellae
, outer layers oF lamellae located beneath the periosteum
and surrounding the outside oF the entire compact bone; and (4)
inner circumferential lamellae
, layers oF lamellae located beneath
the endosteum and Forming the innermost layer oF compact bone. The
is a central space through which blood
vessels pass; the
is the space that sits perpendicularly to the Haversian canals and Forms the connection between
two Haversian canals.
Functions of Bone
For internal organs, such as the brain, heart, lung, bladder, and reproductive organs.
For the body (e.g., long bones For limbs and skull For the support oF brain and Framework
For Facial Features).
in conjunction with the muscles and nervous system.
Produces blood cells (
) within the medullary cavity oF long bones and cancellous bone.
reserve For the body.
For stored heavy metals in the bone tissues. Removes these toxic materials From blood, thereby
reducing damage to other organs and tissues.
in the middle ear (auditory ossicles: malleus, incus, and stapes).