Bone Structure
central canal
core of osteon; contain blood vessels used to give cells nutrients
articular cartilage
covers surface of joints
endosteal membrane
covers surface of trabeculae
endosteum
covers trabeculae of spongy bone in medullary cavity; contains osteoblasts & osteoclasts
short bone
cube-like; no internal cavities; houses hematopoietic (diploe) cells; mostly spongy bone (patella, carpal)
periosteum
double layer at edge of bone; contains outer & inner (osteogenic) membranes
epiphyseal plate
region of hyaline cartilage that grows during development
epiphyseal line
remnant of epiphyseal plate made of hyaline cartilage
osteon
run down long axis of bone, tubular structure; house lacunae & canaliculi
canaliculi
canals that connect lacunae to each other & to central canal
appositional growth
cartilage forming cells (chondroblasts) in perichondrium; add new cartilage to outside of existing cartilage
lacunae
cavities containing osteocytes
interstitial growth
chondrocytes within lacunae divide & add more matrix between cells
fibrocartilage
compressible with tensile strength; sites of heavy pressure (vertebral discs, knee)
fibrous layer of periosteum
outer layer of the periosteum made up of dense irregular CT
interstitial lamellae
between open spaces of tubular osteons; tied together by circumferential lamina
epiphysis
bone ends; no medullary cavity; spongy bone on inside & compact on outer surface; epiphyseal line
irregular bone
bones that don't fit into other 3 categories; complicated shapes; mostly spongy bone (vertebrae & hip bone)
osteoclasts
breaks down bone; found in inner layer of periosteum & endosteum
compact bone
external surface of bone; made up of layering osteons
endochondral ossification
forms bone cartilage for bone construction; begins at end of 4th week
osteoblasts
forms new bone; found in inner layer of periosteum & endosteum
osteogenic layer of periosteum
inner layer of periosteum that holds osteoblasts & osteoclasts; touches compact bone
medullary cavity
internal open space of diaphysis; contains yellow marrow (red during growth)
spongy bone
internal surface of bone; made up of individual shards (trabeculae); no internal canal bringing blood vessels to cells
concentric lamellae
layers of osteon that run around central canal; sheets of collagen fiber
long bone
longer than wide, has a shaft with 2 ends, mostly compact bone (humerus, femur)
osteocytes
maintains bone matrix; found in lacunae
circumferential lamellae
make up the outer surface of compact bone; tie together intersititial lamina
elastic cartilage
more elastic fibers; ears & epiglottis
hyaline cartilage
most abundant; articular cartilage, costal cartilage, laryngeal cartilage, tracheal & bronchial cartilage, nasal cartilage
trabeculae
needle-like flat pieces of spongy bone; woven together
perpendicular canals
network connecting inside of bone of periosteum to central & medullary cavities; blood supply to compact bone
flat bone
no internal cavities; thin/flat/curved; spongy bone embedded within parallel layers of thin compact bone (sternum, scapula)
intramembranous ossification
occurs in skull, clavicles, flat bones during 8th week to 2 years of life
diaphysis
shaft; contains medullary cavity; made of compact bone
functions of bone
support, protection, movement, mineral storage, hematopoiesis
