Skeletal System Structure, Function, and Disorders

Comprehensive vocabulary flashcards covering the anatomy, cellular biology, hormonal regulation, and clinical disorders of the skeletal system based on the provided lecture notes.

Axial Skeleton

The portion of the skeleton along the body's axis, including the skull, thorax, and vertebral column.

Appendicular Skeleton

The part of the skeleton that appends to the axis, consisting of the shoulder girdle, pelvic girdle, upper limbs, and lower limbs.

Cortical (Compact) Bone

The rigid outside shell of bone that makes up approximately $80\%$ of the skeleton.

Cancellous (Spongy) Bone

The interior of the bone containing trabeculae and spicules in a lattice-like pattern filled with marrow.

Osteoblasts

Bone cells that lay down the extracellular matrix and synthesize and secrete bone constituents; known as 'bone building' cells.

Osteoclasts

Cells that break down the extracellular matrix to remove damaged areas or release minerals; known as 'bone crushing' cells.

Osteocytes

Mature bone cells responsible for maintaining the extracellular matrix.

Osteogenic Cells

Cells that divide to form other types of bone cells.

Hyaline Cartilage

A type of supportive connective tissue with very few protein fibers in its extracellular matrix.

Fibrocartilage

Cartilage characterized by the presence of some elastin fibers.

Elastic Cartilage

Cartilage containing many elastin fibers in the extracellular matrix.

Parathyroid Hormone (PTH)

A hormone released when blood calcium levels decrease; it raises levels by stimulating osteoclasts, promoting kidney reabsorption, and increasing intestinal absorption.

Calcitonin

A hormone released by the thyroid when blood calcium is too high; it inhibits calcium release from bone and reduces osteoclast activity.

Epiphysis

The end part of a long bone.

Diaphysis

The shaft of a long bone which contains bone marrow.

Metaphysis

The widening section of a bone before the end ($epiphysis$).

Tendons

Connective tissue structures that connect muscles to bones.

Ligaments

Connective tissue structures that connect bones to bones.

Synarthroses

Joints that provide little to no mobility.

Amphiarthroses

Joints that provide slight mobility.

Diarthrosis

A highly mobile joint, such as those lined with a synovial membrane.

Bursae

Small synovial sacs that cushion tendons within a joint.

Strains

A stretching or partial-tear injury to a muscle or muscle-tendon unit, commonly in the low back or cervical spine.

Sprains

An incomplete or complete tear of a ligament surrounding a joint, most common in the ankle.

Dislocations

The displacement or separation of bone ends of a joint with loss of articulation; most commonly occurring in the shoulder.

Loose Bodies

Small pieces of bone or cartilage within a joint space resulting from trauma or necrosis.

Meniscus

C-shaped fibrocartilage ($medial$ and $lateral$) between the femur and tibia used for load bearing and shock absorption.

Chondromalacia

Degeneration of articular cartilage often due to patellar dislocation or overuse.

Compartment Syndrome

Increased pressure within a limited space that compromises circulation and function, often causing severe pain out of proportion to the original injury.

Osteomyelitis

An infection of the bone caused by direct contamination, hematogenous spread, or skin lesions.

Osteonecrosis

Bone death caused by ischemia ($loss of blood supply$) due to injury, thrombosis, or corticosteroid use.

Osteosarcoma

The most common primary malignant bone tumor, appearing most frequently in areas of fast bone growth.

Ewing Sarcoma

A common malignant bone tumor typically found in teenagers.

Genu Varum

A torsional deformity commonly referred to as bowleg.

Genu Valgum

A torsional deformity where the knees angle in and touch each other.

Talipes Varus

A foot deformity where the foot is inverted at the heel.

Talipes Valgus

A foot deformity where the foot is everted at the heel.

Talipes Equinus

A foot deformity characterized by plantarflexion, where the toes are lower than the heel.

Talipes Calcaneus

A foot deformity characterized by dorsiflexion, where the heel is below the toes.

Osteogenesis Imperfecta

A condition caused by mutations in genes for collagen, leading to abnormal bone formation.

Scoliosis

A lateral curvature of the spine which can be postural, structural, neuromuscular, or idiopathic.

Osteopenia

A condition characterized by decreased bone density.

Osteoporosis

A metabolic bone disease characterized by decreased bone mass, reduced cancellous bone strength, and high fracture risk.

Osteomalacia

A condition where bone is not mineralized properly and becomes soft or non-rigid, often due to insufficient calcium or phosphate.

Paget Disease

A disorder involving regions of excessive, disorganized bone turnover leading to deformation and fractures.

Rheumatoid Arthritis

An autoimmune disorder where antibodies cause joint inflammation and the formation of granulation tissue called pannus.

Osteoarthritis

Degenerative joint disease where damaged cartilage tries to heal, resulting in the creation of spurs or osteophytes.

Systemic Lupus Erythematous (SLE)

A chronic inflammatory autoimmune disease characterized by antinuclear antibodies ($ANA$) that can affect any organ system.

Systemic Sclerosis

Also known as scleroderma, a condition where collagen deposits in the skin and internal organs.

Gout Syndrome

A metabolic disorder caused by increased serum uric acid leading to crystal precipitation in joints and the formation of tophi.