Cartilage And Bones

Question 1

What are the functions of cartilage?

Answer 1

Provides firmness, elasticity and tensile strength
Shock absorbing in synovial joints
Form fetal skeleton

Question 2

What are the characteristics of cartilage?

Answer 2

Originates from mesenchyme during 5th week
Avascular-nutrition by diffusion
Has 2 types of growth-interstitial (from inside) and appositional (from periphery)
Has poor regeneration and forms fibrous scar

Question 3

What are the major elements of cartilage?

Answer 3

Cells-chondroblasts and chondrocytes
ECM
Perichondrium- CT capsule

Question 4

What are the characteristics of chondroblasts?

Answer 4

Cartilage surface
Basophilic cytoplasm
Synthesize protein
Growth appositionally 
Turn into chondrocytes

Question 5

What are the characteristics of chondrocytes?

Answer 5

Surrounded by matrix
Have lacunae
Produce ECM
Growth interstitially and forms isogenous groups

Question 6

What are the characteristics of ECM?

Answer 6

Contain collagen mostly type 2
Ground substance
2 types:
Territorial- around lacunae, fewer fibers, rich in GAGs and stain intensely
Interterritorial- less stained

Question 7

What are the types of cartilage?

Answer 7

Hyaline
Elastic
Fibrocartilage

Question 8

What are the characteristics of hyaline cartilage?

Answer 8

Perichondrium has collagen type 1 fibers, spindle shaped fibroblasts, blood and lymphatic vessels
Matrix made of collagen type 2
Have chondroblasts and chondrocytes

Question 9

What are the location of hyaline cartilage?

Answer 9

Embryonic skeleton
Most moveable joints (has no perichondrium)
Epiphyseal plates
Costal cartilages
Respiratory system

Question 10

What are the characteristics of elastic cartilage?

Answer 10

Perichondrium
Matrix possess type 2 collagen and elastic fibers
Large lacunae with chondrocytes
No calcification or ossification

Question 11

What are the locations of elastic cartilage?

Answer 11

Ear auricle
External auditory canal
Eustachian tubes
Epiglottis

Question 12

What are the characteristics of fibrocartilage?

Answer 12

No perichondrium
Have collagen type 1 and 2
Lacunae
Found in intervertebral discs, public cartilage and STM joints

Question 13

What is chondrosarcoma?

Answer 13

Cancer of cartilage
Has a wide age range
More predominant in male
Slow growth

Question 14

What are the characteristics of bone?

Answer 14

ECM has mineralized and organic matrix (type 1 collagen and little ground substance)
Withstand compression, deformation and stress
Supplied by blood and lymphatic vessels and nerves

Question 15

What is the bone architecture?

Answer 15

Compact bone-rigid outer shell
Spongy bone-trabecular meshwork
Marrow cavity-reticular CT, fat

Question 16

What are the bone coverings?

Answer 16

Periosteum-dense irregular CT, outer layer contains collagen fibers and Fibroblasts, inner layer is vascularized and has osteoprogenitor cells
Endosteum-has osteoprogenitor cells

Question 17

What are the components of bone matrix?

Answer 17

Organic matrix-type 1 collagen, proteoglycans and multiadhesive glycoproyteins
Inorganic matrix-calcium phosphate and calcium carbonate

Question 18

What are the types of bone cells?

Answer 18

Osteoprogenitor cells
Osteoblasts
Osteocytes
Osteoclasts

Question 19

What are the characteristics of osteoprogenitor cells?

Answer 19

Derived from mesenchymal cells
Found in periosteum and endosteum
Differentiate into osteoblasts
Responsible for appositional growth

Question 20

What are the characteristics of osteoblasts?

Answer 20

Found between bone and CT
Active osteoblasts are cuboidal cells with well developed RER
Inactive osteoblasts are squamous cells

Question 21

What are the characteristics of osteocytes?

Answer 21

Trapped in the matrix
Have lacunae
Communicate to others through canaliculi.

Question 22

What are the characteristics of osteoclasts ?

Answer 22

Giant cells
Multinucleated 
Derived from monocytes 
Have ruffle border
Resorb bone

Question 23

What are some bone cells pathologies?

Answer 23

Osteosarcoma-malignant tumor of osteoblasts, common in teenagers
Osteoblasts sarcoma-Benign tumor of osteoblasts,primary bone deposit
Paget’s disease-uncontrolled osteoclasts activity and production of osteoid by osteoblasts

Question 24

What is the bone microstructure?

Answer 24

Primary (woven)- immature, collagen fibers are irregular, for development and repair
Bone remodeling
SSecondary (lamellar)- mature,strong, collagen fibers in lamella, osteons (Haversian systems)

Question 25

What is the Haversian system?

Answer 25

Unit of compact bone
Has a canal with blood vessels
Form concentric lamellae with lacunae in between
Communicated tranversally through Volkmann’s canal

Question 26

What are the characteristics of mature bone?

Answer 26

Interstitial lamella are remnants of osteons
Outer circumferential lamellae is the outer bone surface laid down by perisosteal osteoblasts
Inner circumferential lamellae is the innner bone surface and is laid down by endosteal osteoblasts

Question 27

What are the types of bone development?

Answer 27

Intrramembranous-flat bones, within CT

Endochondral -cartilage template

Question 28

What are the characteristics of intramembranous bone development?

Answer 28

Mesenchymal cells give osteoblasts and form the primary ossification center
Appositional growth
Osteoblasts give osteocytes
Examples: skull bones

Question 29

What are the characteristics of endochondral bone development?

Answer 29

Hyaline cartilage model
Bony collar
Perichondrion becomes periosteum
Cartilage hypertrophy/calcification
Degradation of chondrocytes
Angiogenesis 
Migration of osteoprogenitor cells
Bone formation
Removal of calcified cartilage

Question 30

What are the different zones in a developing bone?

Answer 30

Zone of ossification
Zone of calcification
Zone of hypertrophy
Zone of proliferation
Zone of reserve cartilage