Bones and Cartilage

Question 1

What are the three types of Cartilage?

Answer 1

1-Hyaline
2-Elastic
3-Fibrocartilage

Question 2

What are 4 main differences between cartilage and CT proper?

Answer 2

1-Avascular
2-Only one cell type-chondrocyte
3-Type II collagen
4-Ground substance has aggregan(in hyaline cartilage) and chondronectin

Question 3

What are cartilage cells derived from?

Answer 3

Mesenchymal stem cells

Question 4

Which amino acids are important for type I collagen?

Answer 4

• Glycine (33%)
• hydroxyproline (modified proline
• hydroxylysine (modified lysine)

Question 5

What is critical for amino acid hydroxylation? (absence may lead to scurvy)

Answer 5

Vitamin C

Question 6

What is the general organization of collagen fibers?

Answer 6

Type I and III fibrils associate to form fibers, type II remains as a fibril with finer structure

Question 7

What gives tensile strength and resilience to cartilage?

Answer 7

proteoglycan aggregates binding to water and ions

Question 8

Hyaline cartilage is _________distributed. It has both _______ and _________ locations

Answer 8

Widely, permanent, transient

Question 9

What is hyaline cartilage primarily made of?

Answer 9

Type II collagen fibrils

Question 10

What attaches cells to the ECM in hyaline cartilage matrices?

Answer 10

Chondronectin

Question 11

What surrounds permanent hyaline cartilage? (except articular)

Answer 11

Perichondrium (Type I fibers)

Question 12

What doe chondroblasts and young chondrocytes do?

Answer 12

Secrete ECM

Question 13

Where do chondrocytes reside?

Answer 13

Lacunae

Question 14

Darker staining Matrix, rich in GAGs, found surrounding lacunae is called what?

Answer 14

Territorial matrix

Question 15

Matrix found in-between individual lacunae is called what?

Answer 15

Interterritorial matrix

Question 16

What are isogenous aggregates?

Answer 16

groups of 4-8 cells that originate from a single chondrocyte (also called nests)

Question 17

<p>What are the two grow mechanisms of cartilage?</p>

Answer 17

<p>1-Appositional growth (perichondrium chondroblastsadd to existing cartilage) 2-Interstitial growth (proliferation and hypertrophy of existing chondrocytes)</p>

Question 18

What is different about elastic cartilage?

Answer 18

matrix contains elastic fibers (more cells/matrix than hyaline cartilage)

Question 19

What is different about fibrocartilage?

Answer 19

Matrix contains type I and type II collagen fibers (very little ground substance, mostly fiber) Pubic symphysis, intervertebral disks

Question 20

What are the regions of mature bone made of?

Answer 20

Outer: compact/cortical bone
Interior: trabecular/spongy/cancellous bone
(these are microscopically identical)

Question 21

What covers the outer surface of bone?

Answer 21

periosteum (attached by sharpey’s fibers)

Question 22

What covers the interior surface of bone?

Answer 22

endosteum

Question 23

what is on the end of long bones instead of periosteum?

Answer 23

articular cartilage

Question 24

What are osteoblasts and osteoclasts derived from?

Answer 24

• bone forming osteoblasts: mesenchyme

- bone resorbing osteoclasts: monocytes

Question 25

Once surrounded by bone matrix, what are osteoblasts?

Answer 25

osteocytes

Question 26

What connects the extended processes of osteocytes in canaliculi?

Answer 26

gap junctions

Question 27

What space is formed under osteoclasts?

Answer 27

howships lacunae

Question 28

What are the main organic and inorganic components of bone matrix?

Answer 28

organic: Type I colagen, gags and proteoglycans
Inorganic: hydroxyapatite

Question 29

What are the two processes by which bone is made?

Answer 29

Intramembranous (loose CT)

Endochondral (cartilage matrix)

Question 30

What are the two steps of bone formation?

Answer 30

1-Primary bone/woven bone

2-secondary bone/lamellar bone

Question 31

What is the bone surrounding haversians canals called?

Answer 31

osteons

Question 32

What are the lateral connections between haversian canals called?

Answer 32

volkmanns canals

Question 33

Growth in diameter of long bones is done by?

Answer 33

intramembranous ossification (also initiates bone formation in diaphysis)

Question 34

Growth in length of long bones is done by?

Answer 34

endochondral ossification at the epiphyseal growth plate

Question 35

What regulates bone growth at the epiphyseal growth plate?

Answer 35

Growth Hormones and chondroblast produced factors

Question 36

Incorrect chondrocyte differentiation resulting in loss of articular cartilage can lead to what?

Answer 36

Osteoarthritis