Bone Flashcards
What does bone contain
cells, vessels, nerve fibers, ECM, and fibers
Function of bone
- storage depot for mineralize
- Make blood cells
- Supports
- Protects
What is the result of pressure applied to bone
bone resorption (breakdown)
What is the result of tension applied to bone
bone deposition (addition)
Long bone components
- Diaphysis (long cylindrical shaft)
- Epiphysis (bulbous ends)
- Medually cavity
- Outer aspect (shell)
Epiphyseal (growth) plate
made up of hyaline cartilage
allows the long bone to grow in length
Periosteum
external connective tissue of bone
Endosteum
inner connective tissue of bone
Outer fibrous layer of active periosteum
protective and supportive. Contains fribroblasts. Forms collagen bundles, contains blood and lymphatic vessels and nerve fiber
Inner cellular layer of active periosteum
allows for bone growth on surface of bone
contains osteoprogenitor cells
Early stage, immature bone cells
Osteoid
soft, organic, non mineralized bone
Sharpey’s fibers
run perpendicular to longitudinal axis of bone. Anchor periosteium to underlying bone to keep it from peeling/sliding off
What do osteoprogenitor cells differentiate into
osteoblasts
Inorganic componetnts of bone matrix
hydroxyapatite crystals (calcium phosphate) - man component bicarb, citrate, Mg++, Na+,K+
Organic components of bone matrix
Mostly type I collagen
proteoglycans
glycoproteins
growth factors
Osteonectin
binds hydroxyapaptite crystals to collagen fibers
Sialoproteins and osteopontin
anchor bone cells to ECM
osteocalcin
traps calcium ions from blood stream so that they can stay in bone matrix to mineralize bone
Bone morphogenic proteins (BMPs)
stimulate mesenchymal cells to differentiate into osteoblasts to start laying down bone
Can use after surgery to promote bone growth
Osteoblasts
synthesize bone
Osteocytes
osteoblasts that migrate into the bone matrix and become completely surrounded by it
Osteoclasts
derived from mononuclear hemopoietic progenitor cells
break down bone, involved in bone remodeling
Bone spicule/traveculae
an island of bone
What does the osteoid look like
a halo
Chronic renal failure (CRF)
results in inadequate calcium and phosphate ions available to mineralize bone
Haversian system
multiple concentric lamellae around one Haversian canal. Contains blood vessels, but not lymphatics
Canaliculi
act as sipping straws for nutrients. Connect to other canaliculi. Point towards the Haversian canal
How do metabolic waste products travel
backwards through canaliculi towards haverisian canal
Ruffled border
located at the face of the matrix that’s to be broken down. Project into subosteoclastic space. Acts to reabsorb
Clear zone
does not have major structures. Only real thing it has is actin microfilaments that form a ring around ruffle border. Acts as a plunger to help osteoclast surface adhere to underlying bone. Makes sure acidic contents of re absorption compartment don’t leak out
Basolateral region
contains all the nuclei and organelles of osteoclast
Comppact (Dense) bone
has no bubbles or spaces
Canellous (spongy) bone
Has lots of holes, filled with marrow. Contains irregular bone lamellae.
Primary bone
first bone formed by osteoblasts
Lines tooth sockets
Secondary bone
lamallae are parallel
stronger, more mineralized
Difference between Haversian system and Volkmann’s canal
Haversian system has concentric lamellae. Volkmann’s canal does not
Rheumatoid Arthritis
Hyaline cartilage damaged. Dis-figuration of hands. Causes pain
Gouty Arthiritis
uric crystals accumulate in joints. Very painful
Rickets
Not enough calcium and/or vitamin D to mineralize bone tissue. Bone matrix remains soft. Caused bow-leggedness
Osteoprorosis
reduction of bone mass. Makes bone weak and prone to fractures
