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What are the types of cartilage?
- 1. Hyaline cartilage
- 2. Elastic cartilage
- 3. Fibrocartilage
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Where is hyaline cartilage found?
- embryonic skeleton
- articular surfaces
- ribs ends
- respiratory system
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Where is elastic cartilage found?
- pinna of the ear
- nose
- epiglottis
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Where is fibrocartilage found?
- intvertebral dics
- symphysis pubis
- menisci of the knee
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What are the parts of cartilage?
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What are the cells in the cartilage?
- 1. Chondroblasts
- 2. Chondrocytes
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Where are the chondroblasts located?
in the chondrogenic layer of the perichondrium
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Where are the chondrocytes located?
in the lacuna within the matrix
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What is found in the matrix of catrilage?
- 1. 40% Collagen Fibers
- 2. Amorphous Ground Substance
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What is an example of Amorphous Ground Substance?
Glycosaminoglycans (GAG'S) : e.g., hyluronic acid, chondrotin sulfate, karatan sulfate
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How does cartilage grow?
- 1. Appositional
- 2. Interstitial
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What is Appositional growth?
division of chondroblasts in the pericondrium
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What is Interstitial growth?
divisionn of chondrocytes located in the lacuna
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What are the types of bone?
- 1. Spongy (Calcellous, Trabecular)
- 2. Compact (Dense)
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What is the difference between spongy and compact bone?
Spongy bone DOES NOT have the osteon of Haversian system, where as compact bone DOES.
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What are the parts of bone?
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What is the inorganic portion of bone?
- Hydroxyapatitie Crystals
- approxiamately 67% of bone (calcium, phosphate, carbonate)
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What is the organic portion of bone?
- 1. ECM- collagen fibers (protiens)approximately 33% of bone
- 2. CellsOsteoprogenitor cells
- Osteoblasts
- Osteocytes
- Osteoclasts
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What are Osteoprogenitor cells?
immature or stem cells that form osteoblasts
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What do osteoblasts do?
form bone called osteoid along surfaces of bone
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What do osteocytes do?
maintain surrounding bone and are located in the lacuna
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What do osteoclasts do?
destroy bone, originate from fusion of blood monocytes
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Where does growth occur on the bone and by what means?
- 1. on the surfaces by APPOSITIONAL at osteogenic layer of periosteum and endosteum
- 2. in length of long bones at EPIPHYSIAL PLATES by growth of hyaline cartilage and eventual replacemant of it with bone
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What is intramembranous ossification/bone formation?
- mesenchyme --> bone formation
- mostly skull bones
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What is endochondral ossification/bone formation?
mesenchyme --> hyaline cartilage model --> cartilage death --> bone formation
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How do fractures heal?
- similar to endochondral ossification
- injury --> bone death --> hyaline cartilage formation --> cartilage death --> bone formation
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Is cartilage avascular or vascular?
avascular
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Does cartilage have nerves
no
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Does cartilage grow?
yes, but very slowly through either appositional or interstitial growth
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Does cartilage have a low or high metibolic rate?
low
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What are the five components of the structure of compact bone?
- 1. Osteon or Haversian System
- 2. Interstitial Lamellae
- 3. Inner Circumferential Lamellae
- 4. Outer Circumferential Lamellea
- 5. Perforating Canal of Volkmann
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What is the Osteon or Haversian System/what are the components?
- central canal of Haversian (parallel to length of bone)
- concentric lamellae
- lacunae that contain osteocytes
- canaliculi that contain osteocyte processes which communicate with other osteocytes via gap junctions
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What does the central canal of Haversian contain?
- endosteum
- blood vessels (small arteries and veins)
- nerve
- may contain lymphatic vessel
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What is interstitial lamellae?
- parts of old osteons located between complete osteons
- lacunae with osteocytes and osteocyte processes in canaliculi
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What is inner circumferential lamellae?
several layers of lamellae next to endosteum of bone marrow cavity
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What is outer circumferential lamellae?
several layers of lamellae next to osteogenic layer of periosteum
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What does the perforating canal of volkmann contain?
- contains same structures as central canal of osteon
- does not have concentric lamellae surrounding the canal
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What are the parts of the long bone?
- diaphysis
- epiphysis
- metaphysis
- articular ends
- marrow cavity (red marrow and yellow marrow)
- coverings (periosteum and endosteum)
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What is the diaphysis?
the shaft of the long bone
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What is the epiphysis?
the ends that articulate with other bones on the long bone
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What is the metaphysis?
- between shaft and ends of the long bone
- location of the epiphyseal plate
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What are the articular ends covered with?
hyaline cartilage
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What is red marrow?
- the site of blood cell production?
- (young people)
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What is yellow marrow?
- mostly fat cells
- (older people)
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Where are the periosteum coverings located?
on the outside of the bone
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Where are the coverings of the endosteum located?
inside surfaces of bone
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What is Wotlff's Law?
bone reponds to stress
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