Cartilage

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Cartilage

• Skeletal cartilage
• Mostly water. No nerves or blood vessels
• Periochondrium
• Basic components
• Chondrocytes
• Lacunae
• Extracellular matrix

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Hyaline Cartilage

• Flexible and resilient
• Articular cartilages
• Costal cartilages
• Respiratory cartilages
• Nasal cartilages

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Elastic Fibrocartilage

• Elastic cartilage
• Elastic fibers
• External ear Epiglottis
• Fibrocartilage
• Compressible great tensile strength
• Thick collagen fibers
• Menisici intervertebral discs

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Growth

• Appositional Growth
• Interstitial Growth
• Usually ends during adolescence.
• Calcified cartilage is not bone.

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Bone Classification

• 206 bones in the human body. May vary.
• Axial Skeleton
• Appendicular skeleton
• Classified according to shape.
• Long Bonesshaft 2 ends. Bones of the limbs.
• Short Bonescube shaped. Wrist ankle bones.
• Sesamoid Bonessesame seed shaped. Within
  tendonds. Patella.
• Flat BonesThin, flattened, curved. Sternum
  bones of the skull.
• Irregular Bonescomplicated shapes vertebrae
  hip bones.

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Functions of Bones

• Support
• Protection
• Movement
• Mineral StorageHeavy metals.
• Hematopoiesis

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Bone Structure

• Bones are organs.
• Compact Bone
• Spongy Bone
• TrabeculaeRed Marrow
• Long Bone Structure
• Diaphysis
• Medullary cavity
• Yellow bone marrow
• Epiphysis
• Articular cartilage
• Epiphyseal lineepiphyseal plate

• Periosteum
• Fibrous layer
• Osteogenic layer
• Osteoblasts
• Osteoclasts
• Endosteum
• Internal
• Osteoblasts Osteoclasts

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Bone Structure

• Diploeinternal layer of spongy bone.
• Red Marrowin cavities of spongy bone of long
  bones diploe of flat bones.
• In adults, most hematopoeisis happens in the
  heads of the humerus femur and the sternum
  hip bones.

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Microscopic StructureCompact Bone

• Osteon or Haversian System
• Cylinder oriented parallel to the long bone
  structure.
• Like a weight-bearing column.
• Composed of matrix tubes called lamella.
• Layed down the rings of a tree.

• Lamella
• Collagen fibers run in opposite directions
• Resists twisting.
• Haversian Canal
• Volkmanns canals
• Osteocytes
• Lacunae
• Canaliculi
• Connect osteocytes to each other to the blood
  supply.

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Spongy Bone

• Trabeculae
• Aligned to reduce stress
• Canaliculi
• Osteocytes
• Lamellaeirregularly arranged

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Composition of Bone

• Osteoidorganic
• 1/3 of matrix
• Proteins collagen fibers
• Hydroxyapatitesinorganic
• Calcium phosphates
• Hardness

• Bone Markings
• Passageways
• Tendon/ligament/or muscle connections
• See Table on Next Slide

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Osteogenesis OssificationIntramembranous
Ossification
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Endochondral OssificationMost Bones form this way
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Bone Growth

• Do some bones grow throughout life?
• Epiphyseal Plate
• Side abutting the shaftcell divisionpush
  epiphysis away from the diaphysis.
• Transformation ZoneCalcification.
• Osteogenic Zonemarrow cavity formation
• Epiphyseal plate closure
• Appositional Growth--Width

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Bone Growth Remodeling

• Hormonal regulation
• Growth hormone
• Thyroid hormones
• Sex hormones
• Gigantism
• Dwarfism
• 5-7 of bone mass is recycle each week.

• Remodeling
• Some are remodeled more that others.
• Bone depositinjury or stress.
• Osteoid seamunmineralized seam of matrix.
• Calcification front.
• Resorption
• Osteoclasts
• Lysosomal enzymes
• acids

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Calcium ion regulation

• Negative feedback
• Parathyroid Hormone (PTH)
• Stimulates Osteoclasts.
• Raises blood calcium levels.
• Calcitonin (from the thyroid)Encourages calcium
  deposition. Reduces blood calcium levels.
• Homeostasis

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Mechanical Stress

• Gravitation
• Mechanical Stress
• Electrical Impulses

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Repair of Fractures

• Types of fractures
• Nondisplaced
• Displaced
• Complete
• Incomplete
• Linear---parallel to long axis
• Transverseperpendicular to long axis.
• Open
• closed

• Reductionrealignment
• Closed reduction
• Open reductionpins wires used.
• 6-8 weeks healing time

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Bone Repair
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Bone Disorders, Etc

• Osteomalacia
• Rickets
• Osteoporosis
• Causes
• Insufficient exercise.
• Diet poor in calcium protein.
• Abnormal vitamin D receptors.
• Smoking
• Hormone-related conditions

• Treatments
• Calcium supplements
• HRT therapy
• New drugs
• Fluoridated water
• Electrical stimulation
• Ultrasound
• Free vascular fibular graft.
• Bone substitutes