Skeletal System 6: Bone Structure and Function

Practice flashcards covering the structure, cellular composition, matrix, and development processes (ossification) of the skeletal system based on the lecture transcript.

Hemopoesis

The process of blood cell production that occurs within the skeletal system.

Long bone

A bone classification based on shape, such as the femur or humerus.

Diaphysis

The shaft or central part of a long bone.

Epiphysis

The expanded end of a long bone, categorized as either proximal or distal.

Metaphysis

The region in a mature bone between the diaphysis and the epiphysis containing the epiphyseal line.

Articular cartilage

A thin layer of hyaline cartilage covering the joint surface of a bone.

Medullary cavity

The hollow space within the diaphysis that contains yellow bone marrow in adults.

Periosteum

A tough sheath covering the outer surface of bone, consisting of an outer fibrous layer and an inner cellular layer.

Endosteum

An incomplete layer of cells that lines the internal marrow cavity and covers the trabeculae of spongy bone.

Diploë

The specific name for the spongy bone layer found between the layers of compact bone in the flat bones of the skull.

Red bone marrow

The type of marrow responsible for hemopoiesis.

Yellow bone marrow

A fatty tissue found in the medullary cavities of adult long bones which serves as energy storage.

Osteoprogenitor cells

Stem cells derived from mesenchyme that develop into osteoblasts.

Osteoblasts

Cells found on bone surfaces that secrete osteoid to form the bone matrix.

Osteocytes

Mature bone cells that maintain the bone matrix and detect mechanical stress on the bone.

Osteoclasts

Large, multinuclear cells formed from fused monocytes that participate in bone resorption.

Osteoid

The organic component of the bone matrix, consisting of collagen and proteoglycans, making up approximately $35\%$ of the matrix.

Hydroxyapatite

The inorganic component of bone matrix formed by the precipitation of calcium phosphate and calcium hydroxide, represented as $Ca_{10}(PO_4)_6(OH)_2$.

Bone Resorption

The process where the bone matrix is destroyed by proteolytic enzymes and hydrochloric acid ($HCl$) released by osteoclasts.

Trabeculae

The interconnected lattice or scaffold of bone found in spongy bone that provides strength with minimal weight.

Osteon

The basic functional and structural unit of mature compact bone, consisting of concentric lamellae and a central canal.

Canaliculi

Tiny channels that connect lacunae, allowing osteocytes to communicate and exchange nutrients.

Chondroblasts

Specialized cells that produce the matrix of hyaline cartilage.

Chondrocytes

Mature cartilage cells that reside in lacunae and maintain the cartilage matrix.

Perichondrium

A layer of dense irregular connective tissue that surrounds hyaline cartilage.

Interstitial growth

Cartilage growth that occurs within the internal regions of the tissue, resulting in an increase in length.

Appositional growth

Cartilage growth that occurs on the outside edge or surface of the tissue, resulting in an increase in width.

Ossification

Also known as osteogenesis, the process of forming and developing bone connective tissue.

Intramembranous Ossification

A method of bone formation that begins with thickened regions of mesenchyme, producing flat bones of the skull, some facial bones, the mandible, and the clavicle.

Endochondral Ossification

A method of bone formation that begins with a hyaline cartilage model and produces most bones of the skeleton.

Primary ossification center

The first major center of bone formation, typically located in the diaphysis of a long bone.

Secondary ossification center

Centers of bone formation that develop in the epiphyses of bones, often around the time of birth.

Epiphyseal plate

A layer of hyaline cartilage between the epiphysis and diaphysis where lengthwise bone growth occurs.

Epiphyseal line

The remnant of the epiphyseal plate in adults, indicating that the bone has reached its full length.