Bone And Cartilage

Question 1

What are characteristics of collagen?

Answer 1

Avascular, some types contain a perichondrium, and some types contain isogenous groups.

Question 2

What is the perichondrium composed of?

Answer 2

Outer layer- fibroblasts

Inner layer- chondroblasts

Question 3

What are the three types of cartilage?

Answer 3

Hyaline, Elastic, and Fibrocartilage.

Question 4

Give characteristics of hyaline cartilage and where it might be found.

Answer 4

~Type II collagen
~isogenous
~growth is appositional and interstitial

Can be found: external auditory meatus, larynx, tracheal cartilage, bronchial cartilage, fetal long bones, and articular ends of bones.

Question 5

Give characteristics of elastic cartilage and where it might be found.

Answer 5

~Type II collagen
~Chondrocytes located singly

Can be found: auricle of the ear and the epiglottis.

Question 6

Give characteristics of Fibrocartilage and describe where it can be found.

Answer 6

~Type 1 collagen
~Not surrounded by perichondrium
~ Single sparse chondrocytes

Can be found: intervertebral discs, pubic symphysis, insertion of tendons and ligaments, associated with dense connective tissue

Question 7

Give bone tissue characteristics.

Answer 7

Highly vascular
Based on canalicular system
Increase in bone length happens through appositional growth of hyaline cartilage.
Very dynamic

Question 8

What is the process of chondrogenisis

Answer 8

Development of chondrocytes..chondroblasts are surrounded by territorial matrix and they divide and add extra layers to the chondroblasts= appositional growth

Question 9

What are the organic and inorganic components of bone?

Answer 9

Osteoid-organic

Hydroxyapatite- inorganic

Question 10

What makes up the periosteum?

Answer 10

Outer layer- cartilage

Inner layer- osteoprogenitor cells

Question 11

What are characteristics of osteoblasts?

Answer 11

Alkaline phosphate and vitamin D3

Question 12

Explain how PTH affects bone.

Answer 12

Low PTH- bone formation with osteoblasts

High PTH- osteoblasts release M-CSF

Question 13

Explain the process of osteoclast formation.

Answer 13

PTH attaches to osteoblast
Osteoblast makes and releases M-CSF
M-CSF attaches to a monocyte
Monocyte now expresses RANK and is considered a macrophage.
RANK binds with RANKL and is now an osteoclast.

Question 14

What does the osteoblast secrete that acts as an inhibitor for RANK

Answer 14

Osteoprotegrin- acts as an inhibitor for RANK and doesn’t allow osteoclast formation.

Question 15

What is the role of calcitonin?

Answer 15

Bone builder

Question 16

What is the mechanism of the osteoclast?

Answer 16

Gets into a groove of bone, releases HCl and Cathepsin K to dissolve the bone.

Question 17

Describe the process of intramembraneous (fetal) bone formation.

Answer 17

Mesenchymal cells make osteoblasts
Osteoblasts secrete osteoid
Osteoid traps osteoblasts= blastema= chondrocytes
mineralization via Calcium ions
Osteoblasts make an epi like layer over the surface of the primary bone by secreting osteoid
Primary ossification site becomes trabeculae
Trabeculae come together to make spongy bone.

Question 18

Describe the process of bone replacing cartilage.

Answer 18

Begins at the diaphysis of the muscle.
Chondrocytes get bigger and secrete vascular endothelial growth factor.
Blood vessels break through perichondrium and bring osteoprogenitor cells.
Hyper chondrocytes die and leave strands of calcification matrix
Osteoblasts use the strands to deposit osteoid.
Osteoid is calcified.

Question 19

What are the components of cartilage?

Answer 19

Cellular components- chondroblasts and chondrocytes

Extracellular matrix- collagen and territorial (high in GAGS low in collagen) and inter-territorial ( low in GAGS high in collagen).