Bone, Cartilage and Osteogenesis - Hovorka Flashcards Preview

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Flashcards in Bone, Cartilage and Osteogenesis - Hovorka Deck (28)
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1

What are the 3 types of cells found in bone?

Osteoblasts
Osteocytes
Osteoclasts

2

Where are osteoblasts found?

At border between bone and periosteum

3

What do osteoblasts secrete?

Uncalcified bone matrix

4

Osteoblasts differentiate from what? Where?

Progenitor cells
Periosteum

5

From what do osteocytes differentiate?

Osteoblasts - only once they are surrounded by calcified bone matrix

6

Where are osteocytes found?

In lacunae

7

How do osteocytes receive nutrients?

From a central artery via their connections to neighboring cells in contact with the artery

8

What type of junctions to the osteocyte processes contain?

Gap junctions

9

What are osteoclasts?

Large, multinucleated cells that degrade bone matrix

10

From what do osteoclasts differentiate?

Monocytes

11

How do osteoclasts degrade bone matrix?

By secretion of protons and lysozomal enzymes

12

Differentiation and activity of osteoclasts increases due to which hormone?

Parathyroid hormone

13

What are the organic components of bone matrix?

Mostly type I collagen
Very little ground substance

14

How does bon become calcified?

By the deposition of calcium phosphate (hydroxyapatite) around the collagen fibers, displacing water

15

How is mature bone matrix organized?

Lamellae and osteons surrounding small central arteries

16

What is periosteum made of?

Dense connective tissue - containing fibroblasts and collagen bundles

17

The periosteum is continuous with what?

The tendons that insert on it

18

Where are the progenitor cells contained?

In the periosteum

19

What is the cylindrical unit of mature bone called?

Osteon

20

What are lamellae?

Rings of calcified bone matrix with collagen fibers oriented in a single direction

21

What contains the vessels and nerves in bone?

Haversian canal (central canal)

22

What are canaliculi?

Canals that interconnect lacunae within the osteon and facilitate the transport of nutrients and wastes between osteocytes

23

What interconnects central canals and periosteum/endosteum?

Perforating canals

24

What are the 5 steps to healing bone?

1. Hematoma
2. Connective tissue invades
3. Precallus - hyaline cartilage model
4. Callus - calcification and ossification of cartilaginous model creates immature bone
5. Mature bone

25

How do nutrients/wastes get in/out of cartilage?

Diffuse through the matrix to/from the surrounding perichondrium

26

What are the 2 cells types in cartilage?

Chondroblasts
Chondrocytes

27

Chondroblasts differentiate from what cells?

Progenitor cells

28

Where are progenitor cells found?

Border between bone and perichondrium