Skeletal System Vocabulary Flashcards

Vocabulary flashcards covering essential terms, anatomical structures, cellular components, bone types, fractures, and joint classifications from the skeletal system lecture.

Bone

Hard and dense connective tissue found in locations where strength and rigidity are required.

Cartilage

A smooth, flexible connective tissue that is less rigid than bone, cushioning joints, reducing friction, and providing smooth surfaces for gliding.

Hematopoiesis

The process of blood cell creation taking place in the bone marrow, producing red blood cells, white blood cells, and platelets.

Axial Skeleton

The division of the skeletal system that forms the longitudinal axis of the body, consisting of the skull, vertebral column, and bony thorax.

Appendicular Skeleton

The division of the skeletal system composed of the limbs (appendages), pectoral girdle, and pelvic girdle.

Ligaments

Strong bands of connective tissue that connect bone to bone, holding joints together and preventing excessive movement.

Compact Bone

A dense, smooth, and homogeneous type of osseous tissue forming a hard outer shell on bones.

Spongy Bone

Osseous tissue composed of small needle-like pieces of bone with many open spaces inside.

Long Bones

Bones that are typically longer than they are wide, featuring a shaft with heads at both ends, composed mostly of compact bone (e.g., femur, humerus).

Short Bones

Generally cube-shaped bones containing mostly spongy bone, such as carpals and tarsals.

Flat Bones

Thin, flattened, and usually curved bones made of thin layers of compact bone surrounding a layer of spongy bone (e.g., skull, ribs, sternum).

Irregular Bones

Bones with complex shapes that do not fit into other shape classification categories, such as vertebrae and hip bones.

Sesamoid Bones

Small, round bones embedded within tendons or ligaments where pressure or friction occurs, protecting tendons from compressive forces.

Diaphysis

The shaft of a long bone, composed mainly of compact bone.

Epiphysis

The ends of a long bone, composed mostly of spongy bone.

Periosteum

A fibrous connective tissue membrane covering the outside of the diaphysis that protects, provides attachment sites, and houses osteoblasts and osteoclasts.

Articular Cartilage

A smooth layer of hyaline cartilage covering the external surface of the epiphyses to decrease friction at joint surfaces.

Medullary Cavity

The cavity of the long bone shaft that contains yellow marrow (mostly fat) in adults and red marrow (for blood cell formation) in infants.

Ossification

The process of bone formation.

Appositional Growth

The process by which bones increase in diameter.

Osteocytes

Mature bone cells encased in the bone matrix that maintain its mineral concentration.

Osteoblasts

Bone-forming cells that sit on the periphery of bone and secrete bone matrix.

Osteoclasts

Multinucleated, bone-destroying cells that sit on bone surfaces, breaking down bone matrix for remodeling and releasing calcium into the blood.

Osteogenic Cells

Bone stem cells found in the periosteum and bone marrow that differentiate into osteoblasts.

Comminuted Fracture

A bone break in which the bone breaks into many fragments; particularly common in the aged.

Greenstick Fracture

An incomplete bone break, common in children whose bones are more flexible than those of adults.

Spiral Fracture

A ragged bone break occurring when excessive twisting forces are applied to a bone; common in sports.

Stages of Repair in Bone Breaks

The four-step healing process of a bone break: (A) Fracture hematoma formation, (B) Cartilaginous callus formation, (C) Replacement with bony callus, and (D) Deposition of compact bone.

Sutures

Immovable joints that connect the bones of the skull.

Mandible

The lower jawbone; the only skull bone attached by a freely movable joint.

Paranasal Sinuses

Hollow portions of bones surrounding the nasal cavity that lighten the skull and provide resonance and amplification to the voice.

Hyoid Bone

The only bone in the body that does not articulate with another bone, serving as a moveable base for the tongue.

Synarthroses

Functionally classified joints that are immovable.

Amphiarthroses

Functionally classified joints that are slightly moveable.

Diarthroses

Functionally classified joints that are freely moveable.

Fibrous Joints

Structurally classified joints where bones are united by fibrous tissue, classified functionally as synarthrosis or largely immovable.

Cartilaginous Joints

Structurally classified joints where bones are connected by cartilage, mostly amphiarthrotic (e.g., pubic symphysis, intervertebral joints).

Synovial Joints

Freely movable joints in which articulating bones are separated by a joint cavity containing synovial fluid.

Bursae

Flattened fibrous sacs lined with synovial membranes and filled with synovial fluid that help reduce friction near joints.

Tendon Sheath

An elongated bursa that wraps completely around a tendon.

Osteoarthritis

The most common chronic form of arthritis, typically related to normal aging processes.

Rheumatoid Arthritis

An autoimmune disease in which the body's immune system attacks the joints, beginning with bilateral inflammation and often leading to deformities.

Gouty Arthritis

Inflammation of joints caused by a deposition of urate crystals from the blood.