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98 Cards in this Set
- Front
- Back
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Bone tissue consist of
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organic matrix, Inorganic minerals and cells
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Formula for Hydroxyapatite crystals
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Ca10(PO4)6(OH)2
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What surrounds Hydroxyapatite crystal to faciliates exchange with body fluids
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hydration shell
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Bone cells
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osteoblast (formation), osteoclast (resorption) Osteocytes (control center)
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50% of the dry weight of bone is
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inorganic matter
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what are the components of hydroxyapatite crystal
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calcium and posphorous
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What are the components of Inorganic matter
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calcium, phosphorus, non-crystalline calcium carbonate, magnesium, potassium, sodium, bicarbonate and citrate
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Organic bone matrix is composed of
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callagen type I and ground substance (proteoglycans and glycoprotein)
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Glycoprotein plays what role in the organic bone matrix
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stimulating and organizing mineralization of type I collagen
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without organic matrix what would the bone texture be
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brittle
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Without inorganic matter, what would bone texture be like
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flexible
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Hardness of bone is from
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mineralization of type I collagen
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Osteoblast originated from
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osteoprogenitor cell in bone marrow and periosteum
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bone apposition
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bone forming
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what are osteocytes
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osteoblast trapped in the bone they formed.
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How do osteoblast lay down bone
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synthesize the matrix (osteoid), then mineralize it
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What are the shape of inactive osteoblast
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flat
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what is the shape of active osteoblast and what organelle is prominent
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cuboidal, rER
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Lacunae
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osteocytes lie in tiny chambers;
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How osteocyte communicate with each other
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gap junction at end of their cytoplasmic processes
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Canaliculi
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osteocyte processes extend through a network of bone channels
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What does the extracellular fluid in the canaliculi do
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transmit mechanical stress and strain and sends nutrition to the osteocytes
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how many osteoblast in each lacuna
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one
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what is osteocyte sensitive to
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mechanical stimuli esp. shear stress
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Is osteocytes long lived or short lived
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long
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What does the osteocytes death trigger
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bone resorption and new bone formation
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Osteoclast originate from
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fusion of monocytes from bone marrow
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large, multinucleated and highly mobile describe which bone cell
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osteoclast
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Osteoclast form a selaed depression on the bone surface
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Howship's lucuna
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Describe the border of osteoclast facing the bone
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folded, irregular, ruffled border. Surrounded by organelle free cytoplasm "clear zone"
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what does the osteoclast excrete
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proteolytic enzyme and protons (acids)
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Osteoclast are activated (stimulated and inhibited) by what cytokines
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stimulated: RANKL and IL-1
inhibit: Osteoprotegrin (OPG) |
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Osteoclast activation by hormones
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thyroid and calcitonin
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Osteoclast activation by parathyroid hormones
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stimulate osteoclast indirectly by stimulating osteoblast to produce IL-1
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Where are osteoclast lysosomal enzyme packaged
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golgi complex
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Briefly describe step of bone resorption
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dissolution of calcium phosphate by Hydrogen ions. bone matrix is removed and absorbed by osteoclast cytoplasm and transfer to the blood
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Where does the periosteum located
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on the outer surface of the bone
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What cells are contained in the periosteum CT layer
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osteoblast and progenitor cells
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what are the two layers of periosteum
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outer fibrous (collagen and fibroblast)
inner cellular (osteogenic) |
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What binds the collagen fibers of the periosteum to the bone
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sharpey's fibers
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What lines the inner cavities of the bone and includes the marrow cavity and trabecular surface
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endosteum
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Gross Architecture Compact
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cortical, lamellar
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cortical
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compact
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lamellar
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compact
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cancellous
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trabecular, spongy
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spongy
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cancellous
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trabecular
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cancellous
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Gross architecture
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compact, cancellous
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Microscopic Architecture
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immature, mature
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immature
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primary, woven
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primary
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immature
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woven
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immature
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mature
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secondary, cortical or canecellous
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secondary cortical or canecellous
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mature
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Embryologic formation
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endochondral, membranous
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endochondral what kind of formation
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embryologic
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membranous what kind of formation
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embryologic
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Endosteum is composed of what
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single layer of osteoprogenitor
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enosteum and periostem supply a constant supply of
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osteoblast
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In cortical bone there usually what in the shell
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cancellous bone
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Where is the mandible cortical
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everywhere, except the alveolar process
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maxilla consist of
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cortical plates filled w/ alveolar process w/ cancellous bone
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concentric layer in cortical bone called
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lamellae
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what is the vertical column that surrounds a central blood vessel in cortical bone
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osteon or haversian
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how are the collagen fibers in each lamella arranged
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right angle
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what is the structure b/w osteons in cortical bone
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interstitial lamellae
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Circumferential lamella is
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outer surface of the cortical bone
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inner circumferential lamellae
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Cortical bone: marrow cavity
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what is in center of haersian system (osteon)
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blood vessel, nerve and loose CT
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In Cortical bone, what connects central canal and marrow cavity
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Volkmann's canal
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hypomineralized matrix that is randomly aligned collagen fiber is
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immature bone
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What is the first formed bone in development and regeneration
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immature bone
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What is remodel into mature boen either compact or cancellous
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immature bone
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Tooth sockets are examples of
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primary bone
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Development and secondary growth, bone is formed in a scaffold of
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mesenchymal tissue
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how is craniofacial bone formed
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intramembranous bone
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what is not membranous formation of the facial bones
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mandible and skull base
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What bones are membranous formation
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hip, scapula, clavicle and sternum and craniofacial
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What happens to primary ossification center in membranous bone
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ossification of mesenchyme where cells differentiate into osteoblast
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Events of osteoblast in membranous formation
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osteoblast synthesize collagen, which traps cells, osteoblast differentiate into osteocytes
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What bone (development or 2ndry) form in scaffold of cartilage
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endochondral
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Enchondral formation starts as a collar around the scaffold yes, or no
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yes
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Events of endochondral formation
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cartilage cell death - cell hypertorphy - matrix calcification (1ry bone) - 1ry destroyed by osteoclast - open tunnel for vascular invasion - osteoblast invade
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Epiphyseal plate connects what structure
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epiphysis and diaphysis
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Hyper trophy of chondrocytes does what
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makes bone longer; separate epiphysis from diaphysis
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What in the epiphyseal plate is arranged in parallel direction of growth
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chondrocytes
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What are the five zones of epiphyseal plate
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resting, proliferative, hypertrophic, calcified cartilage, ossifaction
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What is in resting zone
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hyaline cartilage
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what happens in the proliferative zone
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proliferation of osteocytes
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Hypertrophy of chondrocytes accumulate what
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glycogen
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calcified cartilage zone what dies
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chondrocytes
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what resorbs calcified cartilage in ossification zone
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osteoclast
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what is the cartilage at the end of epiphysis called
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articular cartilage
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how much of the body calcium in bone
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99%
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calcitonin does what
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keeps osteoclast from destroying the bone, lower serum calcium level
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Parathyroid hormone does what
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stimulates osteoclast bone resorption via osteoblast released IL-1, increase serum calcium
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Parathyroid decrease or increase calcium in serum
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increase
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primary bone tumors and metastasis
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hypercalcemia
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