Exercise Phys 6: Bones, joints and movement

Question 1

Classifications of bone? give brief description

Answer 1

Long bones e.g. femur, tibia. fibular, fingers
- long shaft, two articular surfaces, mostly compact

Short bones e.g. wrist, ankle
- cube shaped, thin layer of compact bone with spongy centre

Flat bones e.g. skull, sternum
- Parallel layers of compact bone and spongy centre

Irregular bones e.g. vertebrae, pelvis
- thin laters of compact bone, surrounding a spongy centre

Sesamoid bones - e.g. patella
- bones embedded in tendon or muscle

LSFIS (late students fail in summer)

Question 2

Describe general bone structure of long bone

Answer 2

Proximal epiphysis (end of bone)
Metaphysis
Diaphysis (shaft)

Metaphysis
Distal epiphysis

Articular cartilage at each end

Bone comprised of compact and spongy bone

Question 3

Two types of bone marrow and their characteristics?

Answer 3

Red bone marrow - production of red blood cells, platelets, most white cells

Yellow bone marrow - (higher fat content) production of some white cells

Question 4

How does fat act as an endocrine organ?

Answer 4

increases serum adiponectin

Question 5

% if spongy/compact bone in Osseous tissue?

Answer 5

75-80% compact (cortical) bone

20-25% spongy (trabecular) bone

Question 6

Describe components of the extracellular matrix of bone

Answer 6

25% water
25% collagen fibres (for flexibility)

50% crystallised mineral salts (for hardness)

• hydroxypatite (calcium phosphate, calcium carbonate)
• mineral deposition in framework formed by collagen fibres - calcification

Question 7

Cell types of bone? Location and function?

Answer 7

Osteogenic cells
- inner periosteum, endosteum, bone canals with blood vessels. Cell division to form osteoblasts

Osteoblasts
- bone building cells. Make and secrete collagen for ECM. Initiate calcification. When trappd in ECM, become osteocytes

Osteocytes
- mature cells. Most numerous. Maintain metabolism, exchanging nutrients and waste with blood. Full range of functions unclear

Osteoclasts
- Large cells formed from fusion of many monocytes. Release enzymes and acids to breakdown ECM - resorption - development, growth, maintenance and repair