bones

Question 1

what is bone made of?

Answer 1

cells (osteoblasts, osteocytes, osteoclasts)

ECM- 20% water, 35% collagen and 40% hydroxyapatite

Question 2

osteoblasts

Answer 2

form bone matrix

formed by osteoprogenitor cells in endoosteum and peristeoum

Question 3

osteocytes

Answer 3

formed when osteoblasts become completely surrounded by matrix.
found in lacunae which are connected by Cannuculi which allow communication.
help maintain bone matrix

Question 4

osteoclasts

Answer 4

formed by macrophages.
involved in reabsorption of bone matrix.
multinucleate.
on bone surface.
large with ruffled border.

Question 5

Ossification of bones

Answer 5

two ways:
Endochondrial: Hyaline cartilage in growth plate is invaded by blood vessels and replaced by bone. Mainly in Long Bones
Intermembranous: Original foetus membrane is replaced by bone. Occurs in flat bones of Skull, Jaw, Clavicle, Face

Question 6

Bone growth

Answer 6

Appositional: Bone added from the periosteum
Interstitial: Bone develops as a result of cell division in the growth plate.

Question 7

Functions of different components of bone

Answer 7

Collagen: 
-High strength under tension
-Gives the bone some flexibility so it doesn't break 
Minerals:
-Make bone stiff 
-High strength under compression

Question 8

How does intermembranous ossification occur

Answer 8

Mesenchymal cells- osteoprogenitor cells- Osteoblasts which lay down new bone
Residual mesenchymal cells form blood vessels and bone marrow

Question 9

Function of compact bone?

Answer 9

Support

Question 10

Function of spongy bone?

Answer 10

Mineral store

Question 11

Function of bone marrow?

Answer 11

Red blood cell formation

Question 12

Function of the periosteum?

Answer 12

Protection

Supplies nutrients