CH 6: Osseous Tissue and Bone Structure

Vocabulary flashcards summarizing key terms and definitions from Chapter 6 on Osseous Tissue and Bone Structure.

Skeletal System

Organ system composed of bones, associated cartilages, ligaments, and connective tissues that supports and protects the body and enables movement.

Axial Skeleton

Division of the skeleton containing 80 bones of the skull, thorax, and vertebral column that form the longitudinal axis of the body.

Appendicular Skeleton

Division of the skeleton with 126 bones of the limbs and the girdles that attach them to the axial skeleton.

Support (Skeletal Function)

Structural framework that gives the body shape and bears the weight of soft organs and tissues.

Mineral & Lipid Storage

Function of bone that stores calcium, phosphate, and lipids within the yellow marrow.

Blood Cell Production

Formation of red and white blood cells and platelets in red bone marrow (hematopoiesis).

Protection (Skeletal Function)

Shielding of vital organs—such as the brain, heart, and lungs—by skeletal structures.

Leverage

Bones act as levers that muscles pull on to produce movement.

Flat Bone

Thin, roughly parallel surfaces (e.g., parietal bone) providing protection and large surface area for muscle attachment.

Sutural (Wormian) Bone

Small, flat, irregular bone found between the flat bones of the skull within sutures.

Long Bone

Elongated bone with a shaft and two ends (e.g., humerus, femur).

Irregular Bone

Complexly shaped bone (e.g., vertebra) that does not fit other categories.

Sesamoid Bone

Small, round bone embedded in a tendon (e.g., patella).

Short Bone

Boxlike bone with approximately equal dimensions (e.g., carpal bones).

Surface Marking

Any structural feature on a bone that reflects functional adaptation such as attachment sites, passages, or articulations.

Process

Any projection or bump on a bone.

Tubercle

Small, rounded projection for tendon or ligament attachment.

Tuberosity

Rough projection taking up a broad area for muscle attachment.

Trochlea

Smooth, grooved articular process shaped like a pulley.

Condyle

Smooth, rounded articular process that forms a joint.

Trochanter

Large, rough projection found only on the femur.

Facet

Small, flat articular surface.

Crest

Prominent ridge on a bone.

Line

Low, delicate ridge less prominent than a crest.

Spine (Bone)

Pointed or narrow process.

Ramus

Extension of a bone that forms an angle with the rest of the structure.

Canal/Meatus

Large passageway through a bone (e.g., auditory meatus).

Sinus

Air-filled chamber within a bone that lightens the skull.

Foramen

Small, rounded opening for blood vessels or nerves (e.g., foramina of skull).

Fissure

Elongated cleft or gap in a bone.

Sulcus

Deep, narrow groove accommodating a vessel, nerve, or tendon.

Fossa

Shallow depression or recess on a bone surface.

Epiphysis

Expanded end of a long bone consisting mostly of spongy bone and covered by articular cartilage.

Metaphysis

Narrow region that connects the epiphysis to the diaphysis.

Diaphysis

Long tubular shaft of a long bone containing the medullary cavity and thick compact bone walls.

Medullary Cavity

Central cavity within the diaphysis that houses red or yellow marrow.

Articular Cartilage

Hyaline cartilage covering bone surfaces at joints; avascular and nourished by synovial fluid.

Nutrient Artery

Major vessel entering the bone through a nutrient foramen to supply the medullary cavity and inner compact bone.

Nutrient Foramen

Small opening in bone that allows passage of a nutrient artery and vein.

Metaphyseal Vessels

Arteries and veins that supply blood to and from the metaphysis and epiphyseal regions.

Periosteum

Fibrous outer covering of bone containing osteogenic cells, blood vessels, and nerves.

Endosteum

Cellular membrane lining the medullary cavity and trabeculae; contains osteogenic cells.

Osteocyte

Mature bone cell residing in a lacuna that maintains bone matrix and communicates via canaliculi.

Osteoblast

Bone-forming cell that secretes osteoid and initiates mineralization; becomes an osteocyte when entrapped.

Osteogenic Cell

Mesenchymal stem cell that differentiates into osteoblasts; vital for growth and fracture repair.

Osteoclast

Large multinucleated cell that resorbs bone matrix by osteolysis.

Osteon (Haversian System)

Structural unit of compact bone consisting of concentric lamellae around a central canal.

Lamellae

Layered rings of bone matrix within osteons (concentric) or filling spaces (interstitial, circumferential).

Central (Haversian) Canal

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

Canaliculi

Microscopic passageways connecting lacunae and enabling nutrient/waste exchange among osteocytes.

Trabeculae

Interconnecting struts of spongy bone that distribute stresses and house red marrow.

Appositional Growth

Increase in bone diameter by addition of bone matrix beneath the periosteum.

Endochondral Ossification

Process in which hyaline cartilage model is replaced by bone, forming most of the skeleton.

Primary Ossification Center

First location in the diaphysis where bone replaces cartilage during endochondral ossification.

Secondary Ossification Center

Region in each epiphysis where bone formation occurs after the primary center.

Epiphyseal Closure

Fusion of epiphyseal cartilage into bone, leaving an epiphyseal line and ending longitudinal growth.

Intramembranous Ossification

Bone formation within fibrous connective tissue without a cartilage model, producing dermal bones.

Spicule

Small strut of developing bone formed during intramembranous ossification.

Pituitary Growth Failure

Condition causing abnormally short bones due to insufficient growth hormone in childhood.

Achondroplasia

Genetic disorder where epiphyseal cartilage grows slowly, leading to short limbs but normal trunk size.

Marfan’s Syndrome

Inherited disorder with excessive cartilage at epiphyses, resulting in tall stature and connective-tissue problems.

Gigantism

Overproduction of growth hormone before puberty, producing extreme height.

Acromegaly

Excess growth hormone after epiphyseal closure causing thickened bones of face, jaw, and hands.

Fibrodysplasia Ossificans Progressiva (FOP)

Rare mutation causing soft tissues to ossify, forming bone in muscles and other locations.

Congenital Talipes Equinovarus (Clubfoot)

Developmental deformity where feet turn medially and invert; treated with casts or surgery.

Calcium Homeostasis

Regulation of blood calcium by coordinated actions of intestines, bones, and kidneys under hormonal control.

Parathyroid Hormone (PTH)

Hormone that raises blood calcium by stimulating osteoclasts, increasing intestinal absorption, and reducing urinary loss.

Calcitriol

Active form of vitamin D produced by kidneys that enhances intestinal absorption of calcium and phosphate.

Calcitonin

Thyroid hormone that lowers blood calcium by inhibiting osteoclasts and increasing renal calcium excretion.

Fracture Hematoma

Blood clot that forms immediately after a bone fracture, sealing damaged vessels.

Internal Callus

Network of spongy bone uniting the inner edges of a fracture during repair.

External Callus

Cartilage and bone collar stabilizing the outer edges of a fracture.

Closed (Simple) Fracture

Bone break that does not penetrate the skin.

Open (Compound) Fracture

Bone break that protrudes through the skin, posing infection risk.

Transverse Fracture

Break in which the shaft is fractured across its long axis.

Spiral Fracture

Fracture produced by twisting stresses that spread along the bone length.

Displaced Fracture

Fracture where bone fragments are misaligned.

Compression Fracture

Collapse of vertebrae under extreme stress, often linked to osteoporosis.

Greenstick Fracture

Partial fracture in children where one side of the bone breaks and the other bends.

Comminuted Fracture

Fracture that shatters the bone into multiple fragments.

Epiphyseal Fracture

Fracture through the epiphyseal plate that can disrupt growth if not managed.

Pott’s (Bimalleolar) Fracture

Break involving both medial and lateral malleoli at the ankle.

Colles Fracture

Fracture of the distal radius, typically from a fall onto an outstretched hand.