Skeletal System: Bone Structure and Function

Comprehensive vocabulary flashcards covering the anatomy, histology, growth, and regulation of the skeletal system based on Chapter 7 lecture notes.

Skeletal System

A supporting framework of dynamic living tissues that continually rebuilds and remodels itself, consisting of bones, cartilage, ligaments, and other connective tissue.

Hyaline Cartilage

A semirigid, flexible connective tissue containing chondrocytes in lacunae; it forms the fetal skeleton model and covers joint surfaces as articular cartilage.

Fibrocartilage

A type of cartilage containing collagen fibers and chondrocytes in lacunae, known for its ground substance and structural integrity.

Tendon

Dense regular connective tissue that connects muscle to bone.

Ligament

Dense regular connective tissue that connects bone to bone.

Hematopoiesis

The process of blood cell and platelet production which occurs in red bone marrow connective tissue.

Red Bone Marrow

Hemopoietic myeloid tissue located in the spongy bone and medullary cavity of children, and in the spongy bone of adults.

Yellow Bone Marrow

A fatty substance stored within the medullary cavities of adult long bones.

Long Bones

Bones that are classified as being taller than they are wide.

Short Bones

Bones that have an equal length and width.

Flat Bones

Bones that are flat and may be slightly curved.

Irregular Bones

Bones with complex shapes that do not fit into other categories.

Diaphysis

The shaft of a long bone containing a hollow space called the medullary cavity.

Epiphysis

The end of a long bone (proximal or distal) composed of an outer thin layer of compact bone and an inner region of spongy bone.

Articular Cartilage

A thin layer of hyaline cartilage covering joint surfaces to reduce friction and absorb shock in moveable joints.

Metaphysis

The region of a long bone located between the diaphysis and the epiphysis containing the growth plate.

Epiphyseal (Growth) Plate

A thin layer of hyaline cartilage located in the metaphysis that provides for lengthwise bone growth.

Periosteum

A tough sheath covering the outer surface of bone consisting of an outer fibrous layer of dense irregular CT and an inner cellular layer with osteoblasts and osteoclasts.

Endosteum

A membrane covering all internal surfaces of bone within the medullary cavity, containing osteoprogenitor cells, osteoblasts, and osteoclasts.

Osteoprogenitor Cells

Stem cells that produce osteoblasts.

Osteoblasts

Cells that produce the bone matrix.

Osteocytes

Mature bone cells located in lacunae that maintain the bone matrix.

Osteoclasts

Cells that reabsorb bone matrix using enzymes and $HCl$.

Osteoid

The organic component of bone matrix produced by osteoblasts, consisting of collagen protein and semisolid ground substance.

Hydroxyapatite

Inorganic salt crystals that harden the bone matrix and account for the rigidity of bones.

Osteon

The basic functional and structural unit of mature compact bone, also known as a Haversian system.

Central Canal

A channel at the center of an osteon containing blood vessels and nerves.

Concentric Lamellae

Rings of bone connective tissue that surround the central canal of an osteon.

Canaliculi

Tiny canals occupied by osteocyte processes that allow for the transfer of nutrients and waste between cells through gap junctions.

Perforating (Volkmann) Canals

Canals running perpendicular to central canals that connect central canals within different osteons.

Trabeculae

An open lattice of narrow rods and plates of bone found in spongy bone tissue.

Chondroblasts

Cells that produce the cartilage matrix.

Interstitial Growth

Skeletal growth in length that occurs deep in cartilage beginning during embryologic development.

Appositional Growth

Growth in width or diameter that occurs on the outside edge of cartilage or within the periosteum of bone.

Ossification (Osteogenesis)

The process of formation and development of bone connective tissue.

Intramembranous Ossification

Bone growth within a membrane that forms many skull bones, starting with the thickening of mesenchyme.

Endochondral Ossification

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

Calcitriol

A hormone produced via the skin, liver, and kidneys that stimulates the absorption of calcium ions from the small intestine into the blood.

Parathyroid Hormone (PTH)

A hormone released by parathyroid glands in response to reduced blood calcium that increases osteoclast activity and kidney calcium reabsorption.

Calcitonin

A hormone released from the thyroid gland in response to high blood calcium levels that inhibits osteoclast activity and increases calcium loss in urine.