Lab 6: Bone Histology - Cells, Compact Bone, and Spongy Bone

(Anatomy & Physiology I)

Osteoblast

Bone-forming cell that produces and builds bone matrix.

Osteocyte

Mature bone cell that maintains bone tissue. Located in lacunae.

Lacunae

Where are osteocytes located?

Osteoclast

Bone-resorbing cell that breaks down bone matrix using lysosomes.

Osteogenic cell

Bone stem cell that can develop into osteoblasts.

Bone matrix

Combination of bone cells and extracellular matrix.

Extracellular matrix

Nonliving material surrounding bone cells. Contains collagen fibers and minerals.

Lamella

Layer of extracellular bone matrix.

Collagen fibers

Protein fibers that provide flexibility and strength to bone.

Compact bone

Dense outer layer of bone that provides strength and support.

Osteon

Basic structural unit of compact bone.

Central canal

Canal in the center of an osteon containing arteries, veins, and nerves.

Concentric lamellae

Circular layers of bone matrix surrounding the central canal.

Lacuna

Small space that contains an osteocyte.

Canaliculus, canaliculi

Tiny channels connecting lacunae that allow nutrient and waste exchange between osteocytes.

Interstitial lamellae

Remnants of old osteons located between newer osteons.

Circumferential lamellae

Layers of bone matrix that surround the outer and inner surfaces of compact bone.

Perforating canals

Channels that connect central canals to blood vessels on the outside of bone.

Spongy bone

Lightweight bone tissue made of trabeculae. Contains red bone marrow.

Red bone marrow

What does spongy bone contain?

Trabeculae

Thin plates or beams of spongy bone that provide support.

Parallel lamellae

Layers of bone matrix arranged along trabeculae.

Lacunae in spongy bone

Spaces containing osteocytes within trabeculae. (Spongy bone)

Canaliculi in spongy bone

Tiny channels connecting osteocytes within trabeculae. (Spongy bone)

Periosteum

Outer covering of bone made of dense irregular connective tissue. Protects bone and provides attachment for tendons and ligaments.

Dense irregular connective tissue

What kind of tissue covers the periosteum?

Dense irregular connective tissue

Tissue with collagen fibers arranged in many directions. Provides strength in multiple directions.

Sharpey’s fibers, perforating fibers

Collagen fibers that attach the periosteum firmly to bone.

Endosteum

Thin inner membrane lining the medullary cavity and internal bone surfaces.

Yellow bone marrow

Adipose connective tissue that stores energy as fat.

Red bone marrow

Reticular connective tissue responsible for producing blood cells.

Medullary cavity

Hollow central space inside a long bone containing bone marrow.

Nutrient canals

Passageways that allow blood vessels to enter bone.