Skeletal System and Bone Tissue Vocabulary

Vocabulary flashcards generated from lecture notes covering cartilage types, bone structures, bone markings, remodeling processes, fracture types, and skeletal diseases.

Skeleton cartilage

Highly resilient, molded cartilage tissue consisting primarily of water, which contains no blood vessels or nerves.

Perichrondrium

Layers of dense connective tissue surrounding cartilage like a girdle that help resist outward expansion and deliver nutrients via blood vessels.

Chondrocytes

The cells that cartilage is made of, encased in small cavities called lacunae within a jelly-like extracellular matrix.

Lacunae

The small cavities within the jelly-like extracellular matrix in which chondrocytes are encased.

Hyaline cartilage

The most abundant type of cartilage; provides support, flexibility, and resilience, and contains only collagen fibers.

Elastic cartilage

Cartilage similar to hyaline cartilage, found in the external ear and epiglottis.

Fibrocartilage

Cartilage containing thick collagen fibers with great tensile strength, located in the menisci of the knee and vertebral discs.

Appositional growth

Growth in thickness where cartilage-forming cells in the perichondrium secrete matrix against the external face of existing cartilage.

Interstitial growth

Growth in length where chondrocytes within lacunae divide and secrete new matrix, expanding cartilage from within.

Hematopoiesis

Blood cell formation that occurs in red marrow cavities of certain bones.

Osteocalcin

A hormone secreted by bones that helps regulate insulin secretion, glucose levels, and metabolism.

Axial skeleton

Bones forming the long axis of the body, including the skull, vertebral column, and rib cage.

Appendicular skeleton

Bones of the upper and lower limbs, along with the girdles attaching the limbs to the axial skeleton.

Long bones

Bones that are longer than they are wide, present in limbs.

Short bones

Cube-shaped bones found in the wrist and ankle, including sesamoid bones formed within tendons.

Flat bones

Thin, flat, slightly curved bones such as the sternum, scapulae, ribs, and most skull bones.

Irregular bones

Bones with complicated shapes, such as vertebrae and hip bones.

Compact bone

Dense outer layer present on every bone that appears smooth and solid.

Spongy bone

Internal layer of bone made up of a honeycomb of small, needle-like or flat pieces called trabeculae.

Trabeculae

Small, needle-like or flat pieces of bone forming the honeycomb structure of spongy bone.

Diploë

Thin plates of spongy bone covered by compact bone in short, irregular, and flat bones.

Periosteum

White, double-layered membrane covering external bone surfaces except joints, consisting of an outer fibrous layer and an inner osteogenic layer.

Endosteum

Delicate connective tissue membrane covering internal bone surfaces, trabeculae of spongy bone, and lining canals passing through compact bone.

Diaphysis

Tubular shaft forming the long axis of a long bone, consisting of compact bone surrounding a central medullary cavity filled with yellow marrow in adults.

Epiphyses

Ends of long bones consisting of compact bone externally and spongy bone internally.

Epiphyseal line

Remnant of the childhood epiphyseal plate located between the diaphysis and epiphysis.

Red marrow

Tissue found in trabecular cavities of spongy bone and diploë of flat bones where hematopoiesis takes place.

Bone markings

Sites of muscle, ligament, and tendon attachment on external bone surfaces, or areas involved in joint formation or conduits for blood vessels and nerves.

Tuberosity

Large rounded projection on a bone that may be roughened.

Crest

Narrow, usually prominent ridge of bone.

Trochanter

Very large, blunt, irregularly shaped process, with the only examples located on the femur.

Line

Narrow ridge of bone that is less prominent than a crest.

Tubercle

Small rounded projection or process on a bone.

Epicondyle

Raised area on or above a condyle.

Spine

Sharp, slender, often pointed projection on a bone.

Process

Any bony prominence.

Head

Bony expansion carried on a narrow neck.

Facet

Smooth, nearly flat articular surface on a bone.

Condyle

Rounded articular projection on a bone.

Ramus

Armlike bar of bone.

Groove

Furrow on a bone surface.

Fissure

Narrow, slitlike opening through a bone.

Foramen

Round or oval opening through a bone.

Notch

Indentation at the edge of a structure.

Meatus

Canal-like passageway through a bone.

Sinus

Cavity within a bone, filled with air and lined with a mucous membrane.

Fossa

Shallow, basin-like depression in a bone, often serving as an articular surface.

Epiphyseal plate closure

Fusion of the epiphysis and diaphysis that halts bone lengthening, occurring around $18\,\text{years}$ of age for females and $21\,\text{years}$ for males.

Bone remodeling

Process consisting of both bone deposit and bone resorption coordinated by adjacent packets of osteoblasts and osteoclasts.

Parathyroid hormone

Hormone produced by parathyroid glands in response to low blood calcium levels that stimulates osteoclasts to resorb bone.

Calcitonin

Hormone produced by parafollicular cells of the thyroid gland in response to high blood calcium levels.

Leptin

Hormone released by adipose tissue that may regulate bone density by inhibiting osteoblasts.

Serotonin

Neurotransmitter that regulates mood and sleep and interferes with osteoblast activity after meals.

Hypocalcemia

Condition caused by low levels of blood calcium leading to hyperexcitability.

Hypercalcemia

Condition caused by high levels of blood calcium leading to unresponsiveness.

Wolff's law

Law stating that bones grow or remodel in response to demands placed on them.

Nondisplaced fracture

Fracture where bone ends retain their normal position.

Displaced fracture

Fracture where bone ends are out of normal alignment.

Complete fracture

Fracture where the bone is broken all the way through.

Incomplete fracture

Fracture where the bone is not broken all the way through.

Compound fracture

Fracture where the broken bone penetrates the skin.

Simple fracture

Fracture where the skin is not penetrated.

Comminuted fracture

Fracture in which bone fragments into $3$ or more pieces, common in the elderly.

Spiral fracture

Ragged break occurring when excessive twisting forces are applied to a bone, common as a sports fracture.

Compression fracture

Fracture in which bone is crushed, common in porous bones subject to extreme trauma.

Epiphyseal fracture

Fracture in which the epiphysis separates from the diaphysis along the epiphyseal plate.

Depressed fracture

Fracture in which the broken bone portion is pressed inward, typical of skull fractures.

Greenstick fracture

Incomplete fracture where one side of the shaft breaks and the other side bends, common in children.

Closed reduction

Realignment procedure where a physician manipulates broken bone ends back into position without surgery.

Open reduction

Realignment procedure where surgical pins or wires secure broken bone ends.

Hematoma

Mass of clotted blood that forms at a fracture site due to torn blood vessels hemorrhaging.

Fibrocartilaginous callus

Mass of repair tissue consisting of collagen fibers, cartilage, and osteogenic cells spanning a fracture break.

Bony callus

Hard callus composed of spongy bone that replaces the fibrocartilaginous callus during bone repair.

Osteomalacia

Disease in which bones are poorly mineralized because osteoid is produced but calcium salts are inadequately deposited, causing soft, weak bones.

Rickets

Osteomalacia in children caused by vitamin D deficiency or insufficient dietary calcium, resulting in bowed legs and bone deformities.

Osteoporosis

Group of diseases in which bone resorption exceeds deposit, leading to a decline in bone mass while matrix remains normal.

Paget's disease

Disease characterized by excessive and haphazard bone deposit and resorption, producing pagetic bone with a high ratio of spongy to compact bone.