anat & phy - Module 5: Cartilage & Bone

Diaphysis

Shaft of a long bone; mainly compact bone.

Epiphysis

Ends of long bone; spongy bone with red marrow.

Metaphysis

Region between diaphysis and epiphysis; includes growth plate.

Medullary cavity

Central cavity in diaphysis; contains yellow marrow.

Spongy bone

Porous bone tissue with trabeculae; lighter and holds marrow.

Trabeculae

Lattice-like bony structures in spongy bone.

Compact bone

Dense, strong bone tissue; forms outer surface of bones.

Nutrient artery

Supplies diaphysis with blood.

Epiphyseal arteries

Supply epiphyses with blood.

Periosteum

Outer covering of bone; has blood vessels, nerves, osteoblasts.

Endosteum

Thin inner membrane lining medullary cavity; contains bone cells.

Osteoclast

Breaks down bone (bone resorption).

Osteoblast

Builds new bone matrix.

Osteocyte

Mature bone cell; maintains bone matrix.

Osteogenic (Osteoprogenitor) cell

Stem cell that gives rise to osteoblasts.

Red marrow

Hematopoietic tissue (makes blood cells).

Yellow marrow

Fat storage, found in the medullary cavity.

Osteon (Haversian system)

Structural unit of compact bone.

Central canal (Haversian canal)

Contains blood vessels/nerves in osteon.

Concentric lamellae

Rings of calcified matrix around central canal.

Circumferential lamellae

Layers of bone matrix around outer surface.

Lacunae

Small cavities housing osteocytes.

Canaliculi

Tiny canals connecting lacunae; allow nutrient/waste exchange.

Perforating canal (Volkmann's canal)

Connects central canals, carries blood vessels/nerves.

Intramembranous ossification

Bone develops directly from mesenchyme (flat bones).

Endochondral ossification

Bone replaces cartilage (long bones).

Periosteal bone collar

Early bone layer around cartilage model in endochondral ossification.

Interstitial bone growth

Growth in length at epiphyseal plate.

Epiphyseal plate (growth plate)

Cartilage plate where bone lengthens.

Appositional bone growth

Growth in width; new bone added to surface.

Remodeling

Continuous bone resorption & deposition.

Rickets

Vitamin D deficiency in children; soft, deformed bones.

Osteomalacia

Soft bones in adults, often due to vitamin D deficiency.

Osteoarthritis

Degeneration of articular cartilage → joint pain/stiffness.

Osteopenia

Reduced bone mass; precursor to osteoporosis.

Osteoporosis

Severe bone density loss; brittle bones.

Long bone

Longer than wide (femur, humerus).

Short bone

Cube-shaped (carpals, tarsals).

Flat bone

Thin, flat surfaces (skull, sternum).

Irregular bone

Complex shape (vertebrae).

Sesamoid bone

Small bones in tendons (patella).

Pneumatized bone

Bones with air spaces (ethmoid).

Chondrocytes

Mature cartilage cells; maintain matrix.

Chondroblasts

Produce cartilage matrix; become chondrocytes.

Hyaline cartilage

Most common; smooth, reduces friction (articular cartilage, nose).

Fibrocartilage

Strong, shock-absorbing; in intervertebral discs, menisci.

Elastic cartilage

Flexible; in ear, epiglottis.

Perichondrium

Dense connective tissue surrounding cartilage (except at joints).

Articular cartilage

Hyaline cartilage at joint surfaces; no perichondrium.

Interstitial cartilage growth

Growth from inside; chondrocytes divide within lacunae.

Appositional cartilage growth

Growth at surface; chondroblasts add new layers.