Bone Structure Flashcards
Long bone
The diaphysis of the long bone is its shaft. The elongated, usually cylindrical, diaphysis provides for the leverage and major weight support of a long bone. The hollow cylindrical space within the diaphysis is called the medullary(Marrow) cavity. And children, this cavity contains red bone marrow, which is later replaced by yellow bone marrow and adults.
Epiphysis
An expanded knobby region called the epiphysis is that each end of a long bone. It is composed of an outer thin layer of compact bone and an inner, More extensive region of spongy bone. Spongy bone within the epiphesis resist stress that is applied from many directions. Covering the joint is a thin layer of highly cartilage called the articular cartilage it helps reduce friction and absorb shock and movable joints.
Metaphysis
Region and a mature bone in between the diaphysis and epiphysis. In children it is called epiphyseal plate, And in adults it is called the epiphyseal line. It becomes compact bone when they are adults instead of cartilage.
Periosteum
A tough sheath that covers the outer surface of bone except for the areas covered by articular cartilage. It consist of two layers outer fibrous layer of density regular connective tissue that protects the bone from surrounding structures, anchors blood vessels and nerves to the surface of the bone, an serves as attachment site for ligaments And tendons.
Intercellular layer includes osteoprogenitor cells, Osteoblast, and osteoclasts.
endoosteum
Incomplete layer of cells that covers all internal surfaces of the bones within the medullary cavity.
Red bone marrow
hemopoietic (blood cells forming) I’m contains reticular connective tissue, immature blood cells, And fat. And children, red bone marrow is located In the spongy bone of most of the bones of the body as well as medullary cavity of long bones. Much of the red bone marrow degenerates and turns into a fatty substance called yellow bone marrow as children mature into adults. As a result, adults have red bone marrow only a selected portions of the axial skeleton, Such as the flat bones of the skull, the vertebrae, the ribs, the sternum, the ossa coxae. Adults also have red bone marrow and the proximal epiphysis of each humerus and femur.
Compact bone
Composed of small cylindrical structures called osteons. Osteon is the basic functional and structural unit of mature compact bone. They are oriented parallel to the diaphysis of the long bone.
The centric analysis cylindrical channel that lies in the center of the ostia on runs parallel to it. Traveling within the central canal are the blood vessels and nerves that supply to the bone.
Osteocytes are mature blood cells found in small spaces between adjacent concentric lamellae.
Lacunae are the small spaces that house and osteocyte
canaliculi are tiny, interconnecting channels within the bone connected tissue that extends from each lacuna, Travel through the lamella, and connect to other lacuane and the central canal.
Perforating canals resembles central canal and that they also contain blood vessels and nerves. Except they run perpendicular to central canals and connect multiple central canals within different osteon’s, Thus creating multiple osteons.
circumferential lamellae are rings of bone immediately internal to the periosteum of the bone or internal to the endosteum. .
Interstitial lamellae are either the components of compact bone that are between osteons or the leftover parts of osteons that have been reabsorbed. They are incomplete and typically have no central canal.
Spongy bone
Contains no osteons. Its structure is an open lattice of narrow rods and plates a bone , trabeulae. trabeculae often form a meshwork of crisscrossing bars and plates of small bone pieces. This structure provides a great distance to stress applied to many directions by distributing the stress throughout the entire framework
Bone cells
osteprogenitor divide by mitosis and become osteoblast. Osteoblast then become trapped and become calcified into osteoclast. Woven bone and its surrounding periosteum form. lamellar bone that replaces woven bone, as compact and spongy bone forms beneath.
