9/14 .Histology Bone - Dennis (Completed) Flashcards
What gives bone its extreme strength? 4
The addition of bone salts (Ca2+)
What are important functions of bones? 4
Hematopoiesis
Storage
Movement, protection, support
Where within a bone, do we find compact bone? 6
External surface of long and flat bones
Lamellar bone (mature bone)
Where do we find spongy bone? 6
Makes up cancellous or trabecullar bone 🍖
Found deep to compact bone
What is the role of spongy bone (trabeculae)? 6
Houses bone marrow
This bone type can be lamellar or woven
What are the characteristics of lamellar bone? 7
Mature/secondary bone
Regular parallel arrangement of collagen fibers
What are the characteristics of woven bone (nonlamellar)? 7
Immature/primary bone
Loose arrangement of collagen fibers
Lower mineral content
More cells
During repair what bone type forms? 7
Woven bone
What part of the bone contains the epiphyseal plate? 8
The Epiphysis
What do we call the elongated shaft of a bone? 8
Diaphysis
Within a bone, what houses the bone marrow? 8
The medullary cavity
What is the metaphysis of a bone? 8
Spongy/cancellous bone between diaphysis and epiphysis
What forms the border between the epiphysis and metaphysis? 8
The epiphyseal plate/line
What tissue makes up the periosteum? What cells does it contain? 9
Dense irregular CT
Contains osteoblasts
What anchors the periosteum to the endosteum? 9
Anchored by sharpey’s fibers (perforating fibers)
What cells are found within the endosteum? 9
Osteoprogenitor cells
Reticular cells
CT fibers
What is present in the Inner layer (cellular layer) of the periosteum? 10
Osteoprogenitor cells which retain their potential in case of bone injury
What components make up bone matrix? 11
Water - 10%
Organic components
Inorganic components
What are the organic components of bone? 11
Type I collagen
Proteoglycans
Osteocalcin, osteopontin, osteonectin
What are the inorganic components of bone matrix? 11
Calcium hydroxyapatite
Mg
K
Na
F
What houses the nerve, artery, and vein that runs through a bone? 12
The central canal (Haversian canal)
What do we call the cylindrical shafts that run through lamellar bone? 12
Ostensibly
What runs between central canals? 12
Perforating canals (volkmann’s canal)
What are cylindrical channels that allows interaction between osteocytes? 12
Canaliculi
What’s the difference between concentric lamellae and outer circumferential lamellae? 12
Concentric lamellae –> ring of bone around central canal
Outer Circumferential lamellae –> ring of bone along periosteum
What are bone stem cells that produce osteoblasts? 15
Osteoprogenitors
What cells initiate/produces and controls mineralization of the osteoid? 15
Osteoblasts (Ob)
What is Osteoid? 15
No mineralized organic matrix that mineralizes over time
What cell is embedded in the matrix and maintains the matrix? 15
Osteocytes (differentiated from osteoblasts)
What cell remodels and resorbs bone? 15
Osteoclasts - has ruffled borders
How do Osteoclasts remodel bone? Why do Osteoclasts remodel bone?15
Using H+ and lysosomal proteins
Damaged or old bone is broken down by the osteoclast. Osteoblasts then must come in to replace the void
What’s the source of Intramembranous Ossification? What type of bones develop from this growth? 17
Bones developing from mesenchyme precursor
Flat bones of skull and some facial bones
mandible
center of clavicle
What’s the source of Endochondral Ossification? What bones develop from this process? 17
Bone develops from a hyaline cartilage model
Extremities Pectoral & pelvic girdle Pelvis Vertebrae Ends of clavicle
What is the process of Intramembraneous Ossification? 18
Ossification centers within mesenchyme form called an osteoid
Osteoid/ossification center undergoes calcification
Woven bone forms first
Spongy and compact bone form
Lamellar bone eventually forms
Walk-through Endochondral ossification. 20
Inner portion of hyaline cartilage model changes shape and deteriorates
Draws osteoprogenitor cells and vasculature to this site
Primary Ossification center forms in the diaphysis with secondary centers on both ends in the epiphysis
What are the four zones of endochondral ossification? 23, 24
Reserve zone/running zone
Proliferative zone
Hypertrophic zone
Vascular invasion zone
Which zone of endochondral ossification is responsible for lengthening of bone and contains primitive hyaline cartilage? 24
Reserve zone
What zone shows shape changes and formation of calcified matrix during endochondral ossification? 24
Hypertrophic zone
What zone shows calcified cartilage and blends with the epiphyseal plate during endochondral ossification? 24
Vascular invasion zone
What growth induces widening of bone? 25
Periosteal bone growth
walk-through of a bone fracture repair. 27
Fracture occurs, hematoma forms
Hematoma replaced (φ/osteoclasts) by fibrocartilage and regenerative BVs
Primary bone forms
Compact bone (secondary bone) forms with the original site now being larger then before break
What are the symptoms of Achondroplasia
Altered spinal curvature
Small midface
Shortening of long bones (dwarfism)
What causes Achondroplasia? 28
Mutation in FGFR3 (autosomal dominant)
What occurs in Osteomalacia? 29
Progressive shortening and bending of bone
What causes Rickets? 30
Defective mineralization of cartilage in growth plate, aka juvenile osteomalacia
What causes Rickets (Juvenile Osteomalacia)? 30
Vitamin D deficiency or decreased Ca2+ intake
What occurs in Osteoporosis? 31
Decrease in bone mass (cant produce organic matrix)
Loss of bone salts (Ca2+)
What is present in the Outer layer (fibrous layer) of the periosteum? 10
Rich in vasculature
Sharpey fibers
Fibroblasts and collagen fibers
What is the Interstitial lamellae? 12
Pieces of old osteon that results from remodeling
