CH 10: Structure and function Flashcards
What is an intense metabolically active tissue?
Bone
What has a unique mechanical characteristics that are determined primarily by the structural components of tissue?
Bone
How much of bone tissue is mineral?
65%
How much of bone tissue is organic matrix?
35%
What is included in organic matrix of bone tissue?
- Lipids
- Collagen
- Noncollagenous protein
What is the major organic constituent of bone and representing about 90% of dry weight of bone?
Type I collagen
What is the remaining 10% of bone composed of?
- Noncollagenous matrix proteins
- Lipids
- Phospholipids
- Proteogylcans
- Phosphoproteins
What is the principal inorganic component of bone that is generally brittle, tolerating only small amounts of deformation before fracture?
Crystalline calcium phosphate hydroxyapatite
What is the remaining tissue volume composed of?
Fluid filled vascular channels and cellular spaces
What is living tissue that is constantly adapting with high metabolic activity?
Bone tissue
What are the three types of bone cells?
Osteoblasts
Osteocytes
Osteoclasts
What are the components of osteoblasts?
- Form bone matrix (osteoid)
- Synthesize Type I Collagen
- Commonly found on a bony surface
- Large volume of endoplastic recticulum, golgi apparatus, and mitchondira to synthesize collage and secrete matrix proteins
- Synthesis, deposition, mineralization of bone
- Derived from bone marrow
- Secrete procollagen on all active bone surfaces
What are the components of osteocytes?
- Demonstrate fewer organelles
- Greater nucleus-to-cytoplasmic ratio
- 90% of mature skeletal tissue
- Function metabolically to control extracellular concentrations of calcium and phosphorus.
How do osteoblasts become osteocytes?
- Synthesizes bone matrix to form layer on bone surface
- Becomes surrounded by mineralized matrix
- Buried into substance of bone tissue
What are actually osteoblasts that are embedded within newly formed mineralized bone matrix?
Osteocytes
What cells are that in an intermediate changeover from osteoblast to osteocyte?
Osteoid
Osteocyte
Osteocytic osteoblasts
When do osteoblasts become osteocytes?
When osteoblast is done forming bone
What are the components of osteoclasts?
- Giant cell multinucleated bone resportion cells
- Synthesize specific acid phosphate enzyme
- Produce hydrogen ions (lower pH environment)
- Reduced pH increases solubility of crystalline phosphate-hydroxyapatite that function to remove organic matrix crystals via acid proteolytic degradation
- Remove thick layer of osteoid covering, allowing osteoblasts to bind to bone
What are the two types of bone
- Normal, mature lamellar bone
- Weak, fragile, immature woven bone
What are the components of woven bone?
- Structurally immature
- Embryologically (primary) fragile
- Weak with random disorganized collagen arrangement
- Not nearly as strong
- More commonly seen in embryos and newborns
- Seen in adults in fracture repair callus, bone tumors, and various bone pathologies
What does the random arrangement of collagen in woven bone allow?
Strength in all directions while preferring strength in no specific direction
What is a unique feature of woven bone?
Can be deposited without any previous part of a cartilaginous model existing
What is the primary function of woven bone?
Provide temporary, quick-acting mechanical support for injured skeletal tissue
