CH 10: Structure and function

Question 1

What is an intense metabolically active tissue?

Answer 1

Bone

Question 2

What has a unique mechanical characteristics that are determined primarily by the structural components of tissue?

Answer 2

Bone

Question 3

How much of bone tissue is mineral?

Answer 3

65%

Question 4

How much of bone tissue is organic matrix?

Answer 4

35%

Question 5

What is included in organic matrix of bone tissue?

Answer 5

• Lipids
• Collagen
• Noncollagenous protein

Question 6

What is the major organic constituent of bone and representing about 90% of dry weight of bone?

Answer 6

Type I collagen

Question 7

What is the remaining 10% of bone composed of?

Answer 7

• Noncollagenous matrix proteins
• Lipids
• Phospholipids
• Proteogylcans
• Phosphoproteins

Question 8

What is the principal inorganic component of bone that is generally brittle, tolerating only small amounts of deformation before fracture?

Answer 8

Crystalline calcium phosphate hydroxyapatite

Question 9

What is the remaining tissue volume composed of?

Answer 9

Fluid filled vascular channels and cellular spaces

Question 10

What is living tissue that is constantly adapting with high metabolic activity?

Answer 10

Bone tissue

Question 11

What are the three types of bone cells?

Answer 11

Osteoblasts
Osteocytes
Osteoclasts

Question 12

What are the components of osteoblasts?

Answer 12

• 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

Question 13

What are the components of osteocytes?

Answer 13

• Demonstrate fewer organelles
• Greater nucleus-to-cytoplasmic ratio
• 90% of mature skeletal tissue
• Function metabolically to control extracellular concentrations of calcium and phosphorus.

Question 14

How do osteoblasts become osteocytes?

Answer 14

• Synthesizes bone matrix to form layer on bone surface
• Becomes surrounded by mineralized matrix
• Buried into substance of bone tissue

Question 15

What are actually osteoblasts that are embedded within newly formed mineralized bone matrix?

Answer 15

Osteocytes

Question 16

What cells are that in an intermediate changeover from osteoblast to osteocyte?

Answer 16

Osteoid
Osteocyte
Osteocytic osteoblasts

Question 17

When do osteoblasts become osteocytes?

Answer 17

When osteoblast is done forming bone

Question 18

What are the components of osteoclasts?

Answer 18

• 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

Question 19

What are the two types of bone

Answer 19

• Normal, mature lamellar bone

- Weak, fragile, immature woven bone

Question 20

What are the components of woven bone?

Answer 20

• 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

Question 21

What does the random arrangement of collagen in woven bone allow?

Answer 21

Strength in all directions while preferring strength in no specific direction

Question 22

What is a unique feature of woven bone?

Answer 22

Can be deposited without any previous part of a cartilaginous model existing

Question 23

What is the primary function of woven bone?

Answer 23

Provide temporary, quick-acting mechanical support for injured skeletal tissue