2.6.3. HISTO LAB - Cartilage and Bone

Question 1

What is a prerequisite for osteoclast formation?

Answer 1

Osteoclast precursors must interact with cells of the osteoblast lineage

Question 2

What is Cbfa1?

Answer 2

An osteoblast-specific transcription factor that is essential for osteoblast differentiation and bone formation

Question 3

What is OPG?

Answer 3

An osteoblast-secreted glycoprotein that functions as a potent inhibitor of osteoclast differentiation and bone resorption

Question 4

How was osteoporosis first treated?

Answer 4

Used a drug designed to inhibit osteoclasts

Question 5

What are chondrocytes?

Answer 5

They make cartilage

Question 6

What are two types of cartilage growth?

Answer 6

Appositional and Interstitial

Question 7

Appositional Growth

Answer 7

maturation and growth of the cells at the periphery of the cartilage

Question 8

Interstitial Growth

Answer 8

Cells in hyaline cartilage can divide and mature near each other; when the cells do this, this causes the cartilage matrix to expand since there is limited space, and the cells are growing and multiplying next to each other

Question 9

3 types of cartilage

Answer 9

Hyaline, Elastic, Firbrocartilage

Question 10

Hyaline Cartilage

Answer 10

• template during embryogenesis
• articular surface of joints of mature bones
• mostly avascular

Question 11

What type of cartilage is hyaline?

Answer 11

Type II, with a high ratio of GAGs and proteins

Question 12

Elastic Cartilage

Answer 12

Looks a lot like hyaline, but it has elastic fibers (hyaline does not)

Question 13

Fibrocartilage

Answer 13

Found in the transition from hyaline cartilage to bone

Lacks a perichondrium and chondrocytes have a feathery appearance (look for columns of nuclei)

Question 14

What type of cartilage if Fibrocartilage?

Answer 14

Type I and Type II

Question 15

Two types of bone growth

Answer 15

Intramembraneous (mesenchyme model)

Endochondral (cartilage model)

Question 16

Age of Bone

Answer 16

Primary (new/woven), Secondary (mature)

Question 17

Types of Bone

Answer 17

Spongy (trabecular) and compact (lamellar)

Question 18

How to prepare bone samples for a slide

Answer 18

Demineralized (organic material is left)

Ground (matrix is left)

Question 19

How does bone develop?

Answer 19

Same process as cartilage:

Homeobox genes → limb outgrowth → early form → pattern differentiation

Question 20

What are homeobox genes

Answer 20

Part of the overall set of instructions for bone development; if this gene is mutated, the end skeletal structure will be modified, most likely NOT in a good way

Question 21

What marks the end of bone growth?

Answer 21

Once the cells are locked in the calcified matrix

Question 22

Intramembranous growth

Answer 22

in the immature CT, the bone becomes formed by osteoblasts inside that CT, so the bone is formed from the inside of the CT

Question 23

Stages of Bone Growth

Answer 23

1. Proliferation
2. Hypertrophy
3. Calcification
4. Ossification

Question 24

Endochondral growth

Answer 24

Shaft forms first with primary ossification center; secondary ossification centers will occur at the terminal ends of the bone to continue its growth (epiphyseal plate)

Question 25

Osteoclast characteristics

Answer 25

• derived from granulocyte/monocyte lineage
• esosinophilic because they contain lots of mitochondria (for proton pumps)
• multinucleated