1.1B Compact and Spongy Bone Tissue

Compact Bone

Located at bone exterior •

Appears white, smooth, and solid •

Composed of osteons and lamellae •

Associated with both periosteum and endosteum bone membranes •

Contains perforating foramen, perforating and Central canals

Spongy Bone

Located internal to compact bone

• Appears porous, with space between bone tissue containing red bone marrow

• Composed of trabeculae

• Associated with endosteum bone membrane

Interstitial Lamellae

Compact bone remains of a partially resorbed osteon found between newer, complete osteons

External Circumferential lamellae

Rings of compact bone that surround the entire outer compact bone surface; found immediately internal to bone periosteum

Osteon

Functional unit of compact bone composed of concentric lamellae and a central cana

Internal circumferential Lamellae

Rings of compact bone that line the inner edge of compact bone tissue; found adjacent to the endosteum

concentric lamellae

Lamellae that surrounds the central canal

what is each lamellae composed of

inorganic crystals deposited between collagen fibers

orientation of fibers regarding lamellae

within each concentric lamellae the collagen fibers are parallel

amongst each adjacent concentric lamelae the parallel collagen fibers are 90 degrees from the one in the adjacent lamellae … creates an alternating patern

how do osteocytes form

osteoblasts that are surrounded by mineralized bone matrix develop into osteocytes

where are osteocytes located

between adjacent coencentric lamellae

where osteocyte cell body housed at

lacunae

caaliculi

the things that HOUSE the extensions of the osteocytes… not the extensiions themselves

what allows bome cells to communicate with eachother

canaliculi connections which are joined through gap junctions

what do the osteocytes closest to the middle of osteon connect to

central canal blood supply

what do the osteocytes connection to eachother allow them to do

exchange of nutrients wastes and respiratory gases

how do osteocytes connect to adjacent osteocytes

through concentric lamellae through gap junctions

what do osteocytes do

monitor stress and respond by stimulating osteoblasts, initiating bone deposition

periosteum

• Connected to compact bone by Perforating Fibers • Double layer bone covering adjacent to compact bone (external circumferential lamellae) • Outer fibrous layer composed of connective tissue • Inner cellular layer contains osteoprogenitor cells, osteoblasts, and osteoclasts

Endosteum

Incomplete cellular layer that lines the canals and internal circumferential lamellae in compact bone

Central Canal

Carry blood vessels and nerves through the center of individual osteons

Perforating Canal

Carries blood vessels and nerves through compact bone, interconnecting the central canals of osteons

Nutrient Foramen

Opening in the bone where vessels and nerves enter and exit

Spongy Bone

Found in the bone interior of bones at various locations depending upon the size and shape of the bone

Trabeculae

open lattice of narrow rods and plates in spongy bone

what are spaces between trabeculae fillled with

bone marrow and blood vessels

what is trabeculae composed of

flattened layers of bone matrix called parallel lamellae

what is located beetween lamellae in spongy bone

osteocytes housed in lacunae

what is the outter surface of the trabeculae

covered by an incomplete endosteum