UNIT 2 - Compact/ Spongy Bones Flashcards
compact bone tissue is arranged in units called
osteons
osteons are …
- aligned in the same direction along lines of stress
- changes over time in response to physical demands placed on skeleton
Central (Haversian) canals
run longitudinally through the bone
concentric lamellae
rings of hard calcified matrix, around canals
compact bone is often called lamellar bone
Perforating (Volkmann’s) Canals
blood vessels, lymph vessels, and nerves from periosteum penetrate the compact bone
The vessels and nerves of perforating canal connect with …
those of medullary cavity, periosteum, and central aversion canal
lacunae
small spaces between lamellae - contain osteocytes
canaliculi
hair like canals that radiate from lacunae in all directions & filled with extracellular fluid
what does the canaliculi connect lacunae with?
other lacunae and with the central canals: providing many routes for blood-born nutrients, oxygen and cellular waste
interstitial lamellae
fill in spaces between osteons in compact bone
*remnants of osteons whose matrix components have been almost completely recycled by osteoclasts
circumferential lamellae
- found @ outer and inner surfaces of bone
- produced during growth of the bone
- covered by periosteum and endosteum
Through the center of each osteon runs the _______
Central (Haversian) Canals
Spongy bone doesn’t contain
osteons
Osteogenesis (Ossification/Bone Growth)
- Process of bone tissue formation
- bone growth continues into early adulthood as we increase in size
- BONES CAN GROW IN THICKNESS THROUGHOUT LIFE
- Ossification in adults serves only for remodeling and repair of bones
ossification
process of replacing other tissues with bone - term specifically refers to formation of bone
The process of bone formation is called _____._____.____
Osteogenesis, Ossification, bone growth
The process of bone destruction is known as ______
bone resorption
calcification
deposition of calcium salts on soft tissues
the skeleton of a human embryo is composed of
fibrous CT membranes OR pieces of hyaline cartilage that resemble bones
Ossification can follow two patterns :
Endochondrial Ossification and Intramembranous ossification
Endochondral ossification
formation of bone within hyaline cartilage
(–> mesenchymal cells are transformed into chondroblasts, which initially produced a hyaline cartilage model of bone
–> subsequently, osteoblasts gradually replace cartilage with bone)
zone of resting cartilage
small scattered chondrocytes that anchor the epiphyseal plate to the bone of epiphysis (cells don’t function in bone growth)
zone of proliferating cartilage (growth zone)
chondrocytes divided to replace those that die at the diaphyseal side of the epiphyseal plate
zone of hypertrophic cartilage (transformation zone )
cell division in the zone of proliferating cartilage and maturation of the cells in the zone of hypertrophic cartilage
-responsible for lengthening of diaphysis
zone of calcified cartilage (osteogenic zone)
-consists of mostly of dead chondrocytes (matrix around them has calcified)
zone of ossification
osteoblasts replace the calcified cartilage by laying down bone matrix
-therefore, the diaphyseal border of the epiphyseal plate is firmly cemented to the bone of diaphysis
