Introduction to Bone and Axial Skeleton - Week 2

Flashcards covering the introduction to bone, including functions, tissue characteristics, types, cells, structure of long and flat bones, and bone formation processes.

Skeletal System Functions

Support, storage of minerals and lipids, blood cell production, protection, and leverage.

Osseous tissue

Another term for bone tissue, a supporting connective tissue containing cells in a matrix.

Osteocytes

The cells found within bone tissue.

Bone Matrix

The non-cellular component of bone tissue, containing calcium salts and collagen and phosphate.

Compact bone

A type of bone tissue characterized by its dense structure.

Spongy bone (Trabecular bone)

A type of bone tissue characterized by a network of thin rods or plates (trabeculae), giving it a porous appearance.

Long bones

Bones that are longer than they are wide, found in arms, legs, hands, and feet (excluding wrists and ankles).

Short bones

Bones that are roughly cube-shaped, found in wrists and ankles (carpals and tarsals).

Flat bones

Thin, flattened, and often slightly curved bones, such as ribs, sternum, shoulder blades, pelvic bones, and skull bones.

Irregular bones

Bones with complex and peculiar shapes, such as vertebrae and facial bones.

Osteon (Haversian system)

The basic functional unit of compact bone.

Lamellae

Ring-like layers of osteocytes organized concentrically around a central canal in compact bone.

Central (Haversian) canal

A canal running lengthwise through the center of an osteon, carrying blood vessels.

Perforating canals

Canals that connect central canals to blood vessels in the periosteum and marrow cavity.

Articular cartilage

Cartilage that protects bone ends within joint areas.

Trabeculae

Thin rods or plates of lamellae that make up spongy bone, with spaces filled with red bone marrow.

Red bone marrow

Tissue filling the spaces between trabeculae in spongy bone, involved in blood cell production.

Osteoblasts

Bone-forming cells that incorporate calcium into the bone matrix via ossification; they become osteocytes when surrounded by matrix.

Osteoclasts

Large cells that break down the bone matrix by secreting acid and enzymes, releasing minerals through a process called resorption.

Resorption

The process by which osteoclasts break down bone matrix and release minerals.

Diaphysis

The central shaft of a long bone, surrounding the medullary cavity.

Medullary cavity

The central cavity within the diaphysis of a long bone, containing yellow marrow.

Endosteum

A membrane that lines the inner surfaces of bone and the spongy bone within the marrow cavity, active during bone growth, remodeling, and repair.

Yellow marrow

Adipose tissue found within the medullary cavity of long bones.

Nutrient foramen

An opening in the diaphysis through which blood vessels enter and exit the bone.

Epiphysis

The expanded portions at each end of a long bone, covered with articular cartilage and containing red marrow.

Epiphyseal line

The remnant of the epiphyseal plate in mature bones, indicating longitudinal growth is complete.

Periosteum

A membrane covering the outer surface of bone, isolating bone from surrounding tissue and providing attachment points for tendons and ligaments.

Epiphyseal plate (Growth plate)

A hyaline cartilage plate found in children and adolescents, serving as the site of longitudinal bone growth.

Diploë

The layer of spongy bone found between two layers of compact bone in flat bones, often containing red bone marrow.

Ossification

The process by which cartilaginous formations are replaced with bone during embryonic development and growth.

Intramembranous ossification

A type of ossification where bone develops directly from fibrous connective tissue, forming flat bones like the skull and mandible.

Endochondral ossification

A type of ossification where bone forms by replacing a hyaline cartilage model, responsible for the formation of most bones of the skeleton.

Calcification

The process of depositing calcium salts within a tissue, occurring during ossification.

Bone remodeling

The continuous process of recycling and renewal of organic and mineral components of the bone matrix, involving osteocytes, osteoclasts, and osteoblasts.

Ossification center

The site where mesenchymal cells cluster and differentiate into osteoblasts to begin intramembranous ossification.

Mesenchymal cells

Stem cells that can differentiate into osteoblasts during bone formation.

Osteoid

Uncalcified bone matrix secreted by osteoblasts before it calcifies.