Class Notes - Cartilage and Bones Flashcards
what is appositional growth
adjacent to perichondrium
what is interstitial growth
within the matrix of the cartilage
chondrocites divide -> move
what are the cells of the bone?
osteoprogenitor cells
osteoblasts
osteocytes
osteoclasts
what are osteoprogenitor cells
- dividing stem cells
- immature bone cells that will differentiate
- youngest
what are osteoblasts
immature bone cells that create a matrix
what are osteocytes
mature cells, surrounded by lacuna
what are osteoclasts
derived from white blood cells, use hydrochloric acid
what is the extracellular matrix of the bone cells made up of
ground substance rich in minerals (hydroxyapatites -> mostly calcium and phosphate)
- collagen
what are the properties of bone tissues?
- resistant to compression
- resistant to tension
- vascularized and innervated
why are bones organs?
- contain all 4 types of connective tissue
- also contain epithelial and nervous tissue
- have numerous and diverse functions
how can you classify bones?
compact/spongy - tissue organization
long/short/flat/irregular - shape
diaphysis
elongated shaft of a long bone
epiphyses
the end of a long bone, attached to the shaft
metaphyses
(aka epiphyseal plates or epiphyseal lines)
plate of hyaline cartilage at the junction of the diaphysis (shaft) and epiphysis (end) of most bones in the growing skeleton; provides growth in the length of the bone
periosteum
membrane of fibrous connective tissue that covers the external surface of bones of the skeleton
endosteum
layer of cells lining the internal surfaces of bone, specifically, lining the central canals of osteons and the medullary cavity, and covering the trabeculae of spongy bone
Marrow cavity
what is the internal structure of flat bones
2 outer layers of compact bone
+ spongy bone middle
how are osteocytes organized
osteocytes reside in lacunae
- osteocyte organized into osteons or haversian systems
Haversian canal
tube-shaped unit of mature, compact bone; consists of concentric layers of bone lamellae surrounding a central canal
Lamina
a thin layer or flat plate
what are the steps of Intramembranous ossification?
Centers
Osteoid
Woven
Compact
1st step of intramembranous ossification
(centers)
- ossification centers develop in the fibrous connective tissue membrane
- mesechymal cells cluster and differentiate into osteoblasts forming an ossification center
2nd step of intramembranous ossification
osteoid)
- osteoid is secreted and calcifies
- osteoblasts continue to secrete osteoid, which calcifies in a few days
- trapped osteoblasts become osteocytes
