Overview of the Skeletal System

A dense, homogenous bone tissue, primarily found in long bones, with a continuous extracellular matrix.

A porous, heterogeneous bone tissue, mainly found in short bones. It has many open spaces (trabeculae) and is lighter than compact bone.

The structural unit of compact bone, a cylindrical unit of bone tissue.

Mature bone cell, spider shaped, living in the lacunae of bone.

Tiny cavities in bone that house osteocytes.

Concentric rings of calcified bone matrix (collagen and calcium salts) around the central canal.

The central channel within an osteon that contains blood vessels and nerves.

Tiny channels connecting lacunae, allowing for nutrient transport to osteocytes.

Canals that connect central canals and blood vessels of adjacent osteons, perpendicular to central canals

Small needle-like pieces of bone that make up spongy bone.

Bone stem cells that divide and differentiate into osteoblasts.

Bone-forming cells that secrete the bone matrix.

A break in a bone.

Mature bone cells, derived from osteoblasts. They are the primary bone cells; they can't divide.

A break in the bone that does not penetrate the skin.

Bone cells that break down and remove bone matrix (bone tissue). Essential for bone development, growth, health, and repair.

The organic component of bone, primarily collagen. Gives bones flexibility and tensile strength (ability to resist pulling forces).

A break in the bone that penetrates the skin.

Realignment of the broken bone.

Mineral salts, primarily calcium phosphate, making up about 65% of bone. Provides bone with hardness and compression strength.

Realigning the bone without surgery.

The process of red blood cell formation.

A hormone released by the kidneys that stimulates red blood cell formation.

Realigning the bone using surgery.

Marrow tissue that produces blood cells.

An incomplete fracture, common in children.

The inner cavity of a bone that contains bone marrow.

A complete fracture caused by twisting.

A complete fracture resulting in bone fragments.

Type of bone with a porous appearance.

A complete fracture at a right angle to the bone.

Dense bone, found on the outer surface of bones.

Carpals, tarsals, and patella (knee cap) are examples of these bones.

An incomplete longitudinal break.

Humerus, femur, radius, ulna, tibia, fibula, metacarpals, metatarsals, and phalanges (fingers/toes) are examples of these bones.

A fracture at an angle other than a right angle.

Blood clot forms around the break.

Ribs, sternum, cranial (skull) and facial bones.

Hip bones, vertebrae.

A temporary structure that splints the break.

Fibrocartilage callus replaced by bone.

Permanent bone patch formed.

A hematoma forms at the fracture site, a localized collection of blood.

Fibrocartilage callus formation: Fibroblasts produce fibrocartilage, filling the gap near blood vessels. A temporary patch forms.

A bony callus forms, replacing the fibrocartilage callus via osteoblasts, and filling the space. Bone is now bridging the gap.

Remodeling occurs, as osteoclasts remove excess bone, leading to a permanent patch to the original bone structure.

An incomplete fracture of the bone; commonly found in children.

Fracture in which the bone protrudes through the skin.

Medical procedure for fixing a simple fracture without surgery.

Fracture that breaks a bone into several pieces.

1. Hematoma formation; 2.Fibrocartilage callus formation; 3.Bony callus formation; 4. Remodeling into a permanent patch.

Bone-forming cell.

Bone-resorbing cell.

Inorganic component of bone, primarily calcium phosphate.

6-8 weeks for a normal fracture.

Flat bones develop from sheet-like layers of connective tissue.

Bone develops from a hyaline cartilage model, common for most bones.

Cartilage calcifies in the diaphysis's center (primary ossification center), while epiphyses remain cartilaginous with secondary ossification centers appearing later. The epiphyseal plate separates these centers.

The epiphyseal plate enables longitudinal bone growth during childhood and adolescence. Cartilage is added and replaced by bone on opposite sides of the plate.

Bone thickens due to osteoblasts laying down new compact bone on the outer surface while osteoclasts remove bone from the inner surface.

Growth in length, primarily occurring at the epiphyseal plates where cartilage cells multiply and are replaced by bone.

Growth rate is dictated by hormones, like human growth hormone (hGH) and sex hormones.

Continuous breakdown and rebuilding of bone throughout life, a process involving osteoblasts and osteoclasts.

Bones are constantly remodeled, with different parts being replaced at different rates. For example, the femur may be replaced every 4 months, while other regions may take a lifetime.

Bone growth ceases when the primary and secondary ossification centers meet.

Cells that break down bone matrix (reabsorption).

Cells that build bone matrix.

The continuous process of breaking down and rebuilding bone tissue, crucial for calcium homeostasis and repair.

A hormone that increases blood calcium levels by stimulating bone breakdown.

A hormone that lowers blood calcium levels by inhibiting bone breakdown.

Bone cells that break down bone tissue to release calcium into the blood.

Bone cells that build new bone tissue.

The process of maintaining a stable level of calcium in the blood.

Vitamin crucial for calcium absorption in the intestines and reducing calcium loss in urine.

Bone diseases caused by vitamin D deficiency, leading to weak and soft bones.

The main mineral component of bone tissue, which consists of calcium phosphate crystals.

The rate of exchange of bone calcium components in the human body.