Lecture 6 Flashcards
(100 cards)
Role & Function of Bone
- Provides a rigid framework which
supports & protects body tissues - Forms a system of rigid levers that can be moved by forces from the attaching muscles
The composition & structure of bone yield a material that is
strong despite its relatively light weight
Composition of bone
Mineral
Collagen
Water
Minerals composition of bone weight
60-70% of bone weight
Minerals that make up the bone
Calcium carbonate, calcium phosphate
Also Mg2+, Na2+, Fl
Functions of Minerals that make up the bone
Also Mg2+, Na2+, Fl contribute to growth & development
Give the bone its stiffness; primary determiners of bone’s compressive strength
What type of collagen primarily makes up bone
Type 1
Describe the collagen compostion of bone and teh function
ype 1 collagen, cross-links; protein provides bone with flexibility and contributes to its tensile strength.
What does breakdown of collagen with age decrease?
s bone toughness & strength by up to 60%
Howe much water makes up the bone composition
25-30%
What is the fuction of water in the bone
contributes to bone strength, medium for nutrient diffusion, viscoelasticity
What modulus is tied to collagen of. bone?
Low Young’s modulus of elasticity- meaning?, good tensile strength, poor compressive strength
Why are minerals good for bone
stiff & brittle, good compressive strength
All bones are composed of 2 types of osseous tissue at the macroscopic level name them.
Cortical (compact bone)
Cancellouis bone (trabecular)
Compact bone describe
forms the outer shell/cortex of bone, dense structure similar to ivory
Cancellous (trabecular) bone
within the ‘shell’, honeycomb structure, composed of thin rods/plates (trabeculae) in a loose mesh network; spaces between trabeculae are filled with red bone marrow, porous
Which type of bone is more porous, cancellous or cortical bone?
Cancellous bone is more porous than cortical bone.
How does the porosity of bone affect its composition
The more porous the bone, the smaller the proportion of minerals and greater the proportion of collagen.
What is the main difference between cortical and cancellous bone in terms of mechanical characteristics?
Cortical bone is stiffer and can withstand greater stress but less strain compared to cancellous bone.
What is the advantage of trabecular bone over cortical bone in terms of strain before fracturing?
Trabecular bone, being more spongy, can undergo more strain before fracturing, indicating a large capacity for energy storage.
: Describe the structural characteristics of cortical and cancellous bone in terms of strength and flexibility.
Cortical bone is strong but brittle, while cancellous bone is weak but flexible.
What determines the structure of a bone?
The function of a bone determines its structure.
Which type of bone forms the shafts of long bones?
The shafts of long bones are composed of strong cortical bone.
Question:
How does the relatively high trabecular bone content contribute to the vertebrae?
The relatively high trabecular bone content of the vertebrae contributes to their shock-absorbing capability.