cont. skeletal tissues: cartilage skeletal tissues: …orzo.union.edu/~curreyj/bng-338_files/lecture...
TRANSCRIPT
BNG-338: Lecture 7
Cont. Skeletal Tissues: Cartilage
Skeletal Tissues: Bone
First LBL Presentation on Friday
Wednesday, April 15, 15
Learning ObjectivesDescribe composition of cartilage and types
Describe composition of bone
Name the types of bone cells and describe their roles
Explain the difference between woven and lamellar bone and when they “appear”
Explain the process of intramembranous ossification
Wednesday, April 15, 15
Hyaline Cartilage
Appears glassy in living tissue
60% to 78% of net weight is water
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Elastic CartilageComposed of same components as hyaline cartilage matrix, plus elastic fibers and interconnecting sheets of elastic material
Surrounded by a perichondrium
does not calcify
Wednesday, April 15, 15
Fibrocartilage
Difficult to distinguish from dense regular connective tissue
Existence of fibrocartilage indicated that the tissue is required to resist compressive and shear forces
Wednesday, April 15, 15
Bone
Specialized connective tissue consisting of a mineralized extracellular matrix with cells residing within this matrix
Mineral contained within the matrix is calcium phosphate in the form of hydroxyapatite crystals
Wednesday, April 15, 15
The SEM images of collagen/hydroxyapatite composite materials, recorded at different magnification; (a) parallel view with the fibres, (b–c) perpendicular view with the fibres, (d) high resolution SEM at 80,000× magnification.
Ficai, A et al. Chemical Engineering Journal. 160:2: Pages 794-800
Wednesday, April 15, 15
OsteocytesReside in lacunae surrounded by EC fluid
Osteocytes have “arms” that extend into canaliculi and meet processes of other osteocytes
Can pass ions from one cell to another
Believed to be sensors of mechanical load and deformation and can transmit signals to other cells
Wednesday, April 15, 15
Bone Cells
There are 4 types of bone cells:
osteocytes
osteoprogenitor cells (bone lining cells)
osteoblasts
osteoclasts
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Types of BonesLong bones~ longer in one dimension that the other
Short bones~ nearly equal in length and diameter
Flat bones~ thin and plate like
Irregular or sesamoid bones~ shape does not fit into the 3 previous categories
Wednesday, April 15, 15
BoneCortical (Compact) Bone
Porosity of 5-10%
Pores categorized as Haversian canals, Volkmann’s canals, and resorption cavities
Cancellous (Spongy) Bone
Porosity of 75-95%
Pores are filled with Marrow
Made up of trabeculae, 200um thick
Wednesday, April 15, 15
Bone Continued
Endosteum
Lines marrow cavity and cavities of cortical and cancellous bone
One cell thick which have the capacity to differentiate into osteoblast
Periosteum
Covers outer surface of bone
Contains osteoprogenitor cells
Wednesday, April 15, 15