BONES

Question 1

What are the three types of bone cells

Answer 1

Osteoblasts, osteoclasts, osteoblasts

Question 2

What makes up the organic part of the matrix (30%)

Answer 2

Collagen 1 fibres, GAGs, Proteoglycan, glycoproteins

Question 3

What makes up the inorganic part (70%)

Answer 3

Calcium and phosphate ions

Question 4

Explain osteoprogenitor cells

Answer 4

Spindle shaped cells with pale staining nucleus. It is located in periosteum and endosteum and develops into osteoblasts

Question 5

What are osteoblasts cells

Answer 5

Produce uncalcified ECM called osteoid which is later mineralised to form bone. They lie on the peripheral surface

Question 6

What are osteocytes cells

Answer 6

Osteoblasts become trapped within the calcified within matrix between lamella in lacuna where they form osteocytes. They monitor minerals and proteins to regulate bone mass and maintain connections with other osteoblasts and osteocytes

Question 7

What are osteoclasts cells

Answer 7

Are large multi-nucleated cells made from monocytes and macrophages that resorb bones by releasing H+ ions and lysosomal enzymes. They help remodel injured bones and create pathways for nerves and blood vessels to travel through

Question 8

Explain the histology of woven bone

Answer 8

Consists of osteoid with collagen fibres arranged randomly and is later replaced by mature lamellar bone

Question 9

Explain histology of lamellar bone

Answer 9

Highly organised sheets of mineralised osteoid.

Question 10

List down some features of compact bone

Answer 10

Has lamella arranged into concentric circles to surround a vertical harvesian canal
The harvesian canal transmits neurovascular and lymphatic vessels
Osteocytes that are located between lamellas
Lacuna connected by interconnecting tunnels called caniculi
Volkmanns canal perpendicular to HC interconnects with other arteries of HCs together
Volkmanns canal also transmits blood vessels from the periosteum

Question 11

List down some features of spongy bone

Answer 11

Interior of bones containing large spaces.
Forms an irregular trabeculae
Light porous bone which is strong against multidirectional lines of forces
Lightness of spongy bone that is crucial in locomotion.
Bone marrow fills the spaces of trabeculae.
No volkmans canal or harvesian system

Question 12

What are sharpeys fibres

Answer 12

collagenous bundle of fibres that extend from the periosteum into the outer circumferential that attach the periosteum firmly to the bone.