Anatomy and Microscopic Structure of Bone

Vocabulary practice flashcards covering gross bone anatomy, compact and spongy bone structures, bone marrow types, matrix composition, microscopic osteon organization, and bone fracture repair.

Tendons

Connective tissues that attach muscle to bone.

Ligaments

Connective tissues that attach bone to bone.

Epiphysis

The rounded end of a long bone that is covered with articular cartilage.

Diaphysis

The central shaft of a long bone.

Articular Cartilage

Hyaline cartilage that covers the articular surface of an epiphysis.

Metaphysis

The transitional region of a long bone located between the diaphysis and the epiphysis.

Epiphyseal Plate

A layer of hyaline cartilage, also called the 'growth plate,' that acts as the growth center of a long bone allowing it to lengthen until skeletal maturity is reached in adolescence.

Compact Bone

Dense bone tissue organized into osteons that forms the outer layer of all bones and the diaphysis of long bones, providing strength, protection, and resistance to stress.

Spongy Bone

Also called trabecular or cancellous bone; a porous bone tissue featuring a lattice-like network of trabeculae found within the interior of epiphyses that provides structural support, absorbs shock, reduces weight, and houses marrow.

Trabeculae

The lattice-like structural plates or network of bone tissue found in spongy bone.

Periosteum

A dense connective tissue layer lining the exterior of compact bone that contains osteoblasts, blood vessels, and nerves.

Sharpey's Fibers

Perforating connective tissue fibers that anchor the periosteum to the underlying bone tissue.

Medullary Cavity

The hollow interior space within the diaphysis of a long bone that houses yellow bone marrow.

Endosteum

The internal connective tissue membrane lining the medullary cavity and inner bone surfaces that contains osteoclasts.

Red Marrow

Marrow located in the spaces of spongy bone containing stem cells that differentiate into RBCs, WBCs, and platelets.

Yellow Marrow

Adipose-rich tissue located in the medullary cavity that stores fat as an energy reserve.

Hematopoiesis

The production and development of red blood cells, white blood cells, and platelets by stem cells in red marrow.

Organic Bone Matrix

The $\frac{1}{3}$ fraction of the bone matrix comprised of collagen, which gives bone flexibility, strength, resistance to stretching and twisting, and prevents it from breaking easily.

Inorganic Bone Matrix

The $\frac{2}{3}$ fraction of the bone matrix containing minerals such as $Na$, $K$, $F$, $C$, $Mg$, and hydroxyapatite that make bone hard enough to bear body weight and resist compression, as well as $Ca$ and $P$.

Osteon

The cylindrical, circular structural unit of compact bone.

Lamellae

Ringlike sheets or concentric layers of calcified bone matrix that form an osteon.

Lacunae

Dark, hollow pits located between concentric lamellae that contain osteocytes.

Osteocyte

A mature bone cell residing within a lacuna that maintains bone tissue.

Osteoblasts

Bone-building cells found in the periosteum that synthesize and secrete new bone cells and bone matrix.

Osteoclasts

Bone-resorbing cells found in the endosteum that dissolve and reshape bone matrix.

Haversian Canal

The central canal located at the core of each osteon through which blood vessels pass to supply oxygen and nutrients.

Volkmann's Canal

A transverse canal that connects adjacent Haversian (central) canals to each other.

Canaliculi

Microscopic passageways linking lacunae to each other and to the central canal, allowing nutrients and wastes to diffuse between osteocytes.

Bone Fracture Repair

The healing sequence following a fracture: (1) hematoma formation from severed blood vessels, (2) delivery of nutrients and repair cells by blood vessels, (3) bone matrix generation by periosteal osteoblasts, and (4) bony callus formation and subsequent remodeling into normal bone.