Bone Histology Flashcards
Connective tissue characterized by a mineralized extracellular matrix
Bone
What make up the primary mineralization of bone?
Hydroxyapotite crystals
What is the primary collagen in bone?
Type I collagen fibers
90% of total weight of bone matrix protiens
Also contains
Proteoglycan macromolecules, multiadhesive glycoproteins, Vitamin-K dependent proteins, growth factors; make up small compoenent
Bone
- bone cells, connected via canaliculi.
- Survive 10-20 years.
- Important for maintaining overall structure
- Sense for adaptation
Osteocytes
1 cause of morbitiy in ppl over 80 occurs after what?
bone breakage, seditary
Excersise places pressure on bones causing ____ to secrete more hydroxyappotite making bones denser and stronger
Osteocytes
gives rise to osteoblasts. Respond to markers in ECM, causing htem to differentiaie into osteoblast.
Osteoprogenitor cells
Differentiated bone-forming cell which secretes bone matrix (osteoid matrix)
Osteoblasts
Osteoblasts fo to where the Bone matrix is produced and secretes a _____
Osteoid matrix
Consist of collagen, glycoproteins etc
Osteoid matrix secreted by osteoblasts
Once osteoid matrix is down, ____ is secreted and traps osteoblast in matrix converting them to ___
Hydroxyapotitie, converting to osteocytes
- found on bone surface, derived from osteoblasts.
- Provide a foundation of cells that can quicly differentiate into osteoblasts.
- Bones always under stress microfractures, these cell fix these
Bone lining Cells
- resorb bone they are specialized with enzyme TRAP
Osteoclasts
What is the physiological marker of osteoclasts?
Enzyme TRAP
How do osteoclast function?
- Seal themselves on bone surface
- Clear zone on edge
- Ruffle zone in center, acid released to break down HA, and TRAP breaks down the rest of the EC components.
two types of bone
- Compact (dense)
- Spongey (cancellous
4 classifications of bone
- Long (femur)
- Short (carpals)
- Flat (hip)
- Irregular (vertebrae)
Explain three parts of long bone
- Diaphysis; main shaft
- Metaphysis on middle end
- Epiphysis; on either end lined with articular cartilage to reduce friction.
what part of long bone is cut off with joing replacments?
Metaphysis cut off and replaced with prosthetic
the outer covering of bones
Periosteum
articulating surfaces – then covering is ____; reduce fricion
cartilage
the main component of the periosteum in non-growing bones
Fibrous Layer
- may become osteoblasts with appropriate stimulus
- Important with repair, major break, disrupt periosteal layer, they can differentiatin into osteoblast. Bone producton
Periosteal Cells
In long bones, the bone cavites are line with ____ which contains ___ cells
Endosteum, osteoprogenitor cells
What marrow?
blood producing
Contains blood cells in different stages of development
red marrow cavity
What marrow?
found in adults, mostly fat cells
Can revert to blood producing in cases of extreme blood loss (trauma)
Yellow marrow cavity
organized in concentric lamina called ____ (nerve, artery, vein)
osteon
- Perpendicular to long axis
- Channal where blood vessle and nerve travel through
- Connect to haversian canal
- Metabolic transfer in/out
- Growth factors in
- Calcium control with blood
Volkmann Canals
- parallel with long axis to bone
- Connected to inner and outer surfaces
Haverisian Canal
Where do the nutrient diaphyseal and epiphyseal arteries arise from?
arise from the periosteal buds
Where do the nutrient metaphyseal arterry arise from?
From periosteal vessels during bone widening
Lymphatic drainage only occurs from the ___
Only in the periosteum
No lymphatic vessels in bone tissues
- Not organized – nonlamellar
- More cells per unit area than mature
- Random arrangement
- More ground substance
Immature bone
During development & repair x4
?
**Immature bone **
*lack of mineralization
?
**Mature bone **
*extensive secondary mineralization, organized
Derived from Mesenchymal stem cells
Can differentiate into many cell types: fibroblasts, osteoblasts, chondrocytes, muscle cells
Osteprogenitor cells
Located on internal and external bone surfaces
Osteoblast are responsible for what?
Calcification of the bone matric
How to osteoblast communicate?
Via gap junctions through canaliculi
How do osteocytes connect to one another?
Canaliculi
Mature bone cell enclosed in bone matrix occupying the lacuna
Osteocytes
Osteocytes respond to what?
Mechanical forces via mechanotransduction