9/12 Bone Histology Flashcards
bone segments
compact bone vs. spongy bone
what is the immature bone called? and matured bone?
woven bone and lamellar bone
organic bone vs. inorganic bone
what does the organic bone contain?
what doess the inorganic bone contain?
Osteoprogenitor cells
- Mesenchymal origin w/ properties of stem cells – Proliferative potential – Capacity to differentiate
- Found in inner layer of ____and ____
- Give rise to ______
- Reactivated during times of bone repair
periosteum and endosteum
osteoblasts
Osteoblasts
- Epithelial-like cells w/ ____or ____shapes
- Deposit ____ and control mineralization of osteoid
- Give a strong cytochemical reaction for Alkaline Phosphatase (AlkPhos) – AlkPhos disappears when osteoblasts become osteocytes
cuboidal and columnar
osteoid
Osteocytes
Osteoblasts trapped inside ____ w/in the osteoid matrix they deposited
- Highly branched cells that create a complicated communicating network allowing them to get nutrients to survive
- Life of the bone matrix depends on osteocytes being alive
lacunae
Osteoclasts
- Derived from ______ lineage – Not osteoprogenitor lineage – Originate as monocytes that enter bone via blood stream then form osteoclasts
- Generate a seculded acidic environment for bone resorption – Mediated by H+ -ATPase – Causes enzymatic degradation of organic matrix via ______
- Important role in bone remodeling and renewal
- Reside in Howship’s lacuna
monocyte macrophage
Cathepsin K protease
Osteoclast Differentiation
histology of the bone
Periosteum
Principal functions:
- Nutrition of osseous tissue
- Continuous supply of new cells for growth and repair
- Periosteum does not cover articular surfaces of bone
Periosteum 2 layers
• Inner Layer
o _____ cells
o Osteogenic layer
• Outer Layer
o Rich in blood vessels and nerves
o Fibroblasts and collagen fibers
o Sharpey’s fibers – anchoring collagen fibers penetrate the outer circumferential lamellae
Osteoprogenitor
Endosteum
osteon/haversian system
cement line is surrounded which structure?
osteon
Haversian canal:
• ＿＿＿＿＿ (direction) vascular channel • Housing capillaries and post-capillary venules • Center of osteon
Volkmann’s canal:
• _______ (direction) vascular channels • Connect Haversian canals
Longitudinal
Transverse
osteon/Haversian system
osteon/Haversian system
intramembrane ossification
endochondral ossification is from which structure?
where is the primary ossification center located? and secondary ossification center?
hyaline cartilage
primary - shaft
secondary - head
Zones of Endochondral Ossification
Periosteal Bone Growth
Periosteal Bone Growth
Bone Fracture Repair
what’s are the two critical elements formation for the fracture repair?
Achondroplasia
- Autosomal dominant mutation in _____
- MC form of dwarfism
- Presentation:
– Shortening of proximal extremities – Relatively normal trunk length – Small midface – Altered spinal curvature – Intelligence not usually affected
FGFR3
Rickets
- ____deficiency during growth, which causes a defect in mineralization of cartilage in growth plate
- Caused by insufficient Ca intake or vitamin _____
- Presentation:
– Delayed closure of fontanelles – Bowed lower limbs – Parietal and frontal bossing – Widening of wrists and bowing of distal radius and ulna
calcium
D
Osteomalacia
- Adult form of Rickets – progressive softening and bending of bone
- Caused by vitamin D deficiency or GI disease (MC cause in U.S.)
- Presentation:
– Bone and joint pain – Muscle weakness, spasms, and cramps – Fracture – Difficulty walking/waddling gait
Osteoporosis
- Progressive loss of normal bone density w/ deterioration of its microarchitecture
- Caused by imbalance b/w osteoclast resorption of bone and osteoblast deposition of bone
- MC occurring bone disease
- Commonly occurs in elderly and postmenopausal females
- Presentation: – Easy fractures
