Bone Formation and Growth Flashcards Preview

Week 45: Joint Fracture > Bone Formation and Growth > Flashcards

Flashcards in Bone Formation and Growth Deck (23)
Loading flashcards...
1

Things in the
1. Organic
2. Inorganic
matrix of bone

1. Type 1 collagen, proteoglycans, proteins, growth factors
2. Hydroxyapatite, Ca, P, Mg, citrate, K, Na

2

What type of strength does the
1. Organic
2. Inorganic
matrix give to bone?

1. Tensile strength
2. Compression strength

3

Axial skeleton

Skull
Rib cage
Vertebral column

4

Appendicular skeleton

Limbs
Pelvic girdle
Clavicle
Pectoral girdle

5

2 types of bone

Compact/cortical/dense
Spongy/trabecular/cancellous

6

Periosteum

Covers the outer surface of bones (not where the cartilage is)
Has 2 layers: outer (fibroblasts, collagen, nerves, bvs), and inner (periosteal cells)

7

Sharpey fibers

Anchor the periosteum to the bone
Collagen fibers

8

Endosteum

Inner lining of bones
In contact with bone marrow
Often 1 cell layer thick
Endosteal cells (osteoprogenitor cells and bone lining cells)

9

Osteoprogenitor cells

Precursors for osteoblasts
Cannot tell apart from mesenchymal cells on histology

10

Osteoblasts

Bone forming cells
Secrete: type 1 collagen, bone matrix proteins, glycoproteins and proteoglycans, calcify the bone matrix

11

Osteocytes

Bone maintenance cells
Secrete matrix in response to mechanical stress
Degrade matrix to help maintain calcium homeostasis
Completely embedded in the bone matrix (in lacuna, communicate via canaliculi)

12

Osteoclast

Large, multinucleated cells
Derived from monocyte precursors
Responsible for the resorption of bone
Occupy a shallow canal (howship's lacuna)

13

Osteoporosis

Imbalance between osteoclast mediated resorption and osteoblast mediated bone deposition
Decreased bone mass and enhanced bone fragility

14

Intramembranous bone formation

Develops directly from mesenchyme
No cartilage model precursor
Flat bones of the skull and face, mandible, and clavicle

15

Endochondral bone formation

Cartilage model serves as precursor to bone
Bones of the extremities and axial skeleton that bear weight

16

5 zones of growth plate

Zone of reserve cartilage
Zone of proliferation
Zone of hypertrophy
Zone of calcified cartilage
Zone of resorption

17

Immature bone (woven bone)

No organized lamellae
Contains more cells per unit area
Cells are randomly arranged
Less mineralization
Gets remodelled into either compact or spongy bone

18

Compact bone

Made up of osteons (Haversian system)
Contains a central canal (Haversian canal - contains vascular and nerve supply)

19

Volkmann canals

In compact bone
Connects the endosteum to the periosteum

20

Metaphysis

Area of the bone that flares out
When bone matures and epiphyseal plate closes, clinicans just call the end the metaphysis

21

Metaphyseal inwaisting

Metaphysis gets trimmed as the bone grows so there is not a balloon in the middle

22

Bone metabolizing unit

Contains osteoblasts, osteoclasts, and osteocytes
Cortical bone = osteons
Cancellous bone = trabeculae

23

Wolff's law

Bone will adapt to the loads it is placed under
If loading on a bone increases/decreases the bone will become stronger/weaker to adapt to that