Lecture 17: Bone Flashcards

1
Q

What are the primary functions of the skeleton

A

Support the body
Model body shape and form
Provide a system of levers for locomotion
Protects soft parts and collapsible body cavities

The skeleton has secondary roles in:

  • mineral reserves-calcium and phosphates
  • acid base homeostasis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bone is a composite material of two things, what are they?

A
  1. Meshwork of collagen fibres: soft, flexible, resistant to lengthening
    - resistance to tension
  2. Crystals of hydroxyapatite (calcium phosphate)
    - extremely hard but brittle
    - resistant to compression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is bone constantly being remodelled

A

Bony units- osteons- laid down by osteoblasts; maintained by osteocytes; eaten away by osteoclasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are osteoblasts

A

They lay down the organic matrix osteons which then becomes mineralised to form bone
-full mineralization may take weeks or months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are osteocytes?

A

= osteoblasts entombed by mineralised matrix

  • regulate mineral flux in matrix under hormonal control
  • respond to stresses in bone to control remodelling (ie signals osteoclasts)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are osteoclasts?

A

Large multinucleated cells

  • break down calcified matrix
  • eroded surface attracts osteoblasts and the cycle repeats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When loaded, stress/strain line are concentrated to the outermost parts. True or false

A

True!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is wolffs law?

A

The architecture of bone is dictated by the stresses acting apon it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Bone shape

What are the different kind of loads bone can have?

A

Symmetrical load (pure compression)
Asymmetrical load
Asymmetrical force
Refer to lecture slides for pictures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly