Skeletal System

Question 1

1. Development of Cartilage Model

Answer 1

Mesenchymal cells organize into rough shape of skeleton
Then differentiate into chondroblasts
Chondroblasts then begin producing cartilage
This is surrounded by a membrane called Perichondrium

Question 2

2. Growth of Cartilage Model

Answer 2

Interstitial growth (length) happens via chondrocyte cell division
Appositional growth (width) happens via new cartilage layers added deep to the perichondrium

Chondrocytes in the mid-region burst causing calcification

Question 3

3. Development of Primary Ossification Center

Answer 3

Perichondrium changes to Periosteum

Nutrient artery penetrates the middle of the cartilage model

Osteoblasts deposit bone matrix over calcified cartilage forming spongy bone

New bone development proceeds in both directions

Question 4

4. Formation of Medullary Cavity

Answer 4

Osteoclasts are brought in to the center of the model and break down spongy bone to create hollow medullary cavity

Question 5

5. Development of Secondary Ossification Center

Answer 5

Occurs around the time of birth when cartilage in the epiphysis starts to calcify

Epiphysial artery penetrates the cartilage and brings in osteoblasts to lay down spongy bone over calcified cartilage

Articular cartilage remains and no medullary cavity develops

Question 6

6 Growth in Length

Answer 6

Occurs at epiphysial (growth) plate until the end of puberty

2 Processes:
- Growth of cartilage on epiphysial plate
- Replacement of cartilage with bone on epiphysial plate

As long as above happens keeping pace with each other growth continues

Question 7

5 types of tissues that make up skeletal system

Answer 7

Epithelial
Nervous
Cartilage
Adipose
Blood

Question 8

5 Functions of bone

Answer 8

Attachment point for muscles
Protection
Blood cell production
Energy storage - adipose tissue (yellow bone marrow)
Mineral storage - calcium and phosphate

Question 9

What is the periosteum?

Answer 9

Superficial membrane covering bone
Does NOT cover cartilage

Question 10

What is the endosteum?

Answer 10

Lining of the marrow cavity

Question 11

What is an Osteoprogenitor cell?

Answer 11

Unspecialized bone stem cell

Question 12

What is an osteocyte?

Answer 12

Mature bone cell that maintains bone tissue

Question 13

What does an osteoclast do?

Answer 13

Breaks down bone tissue (remodels)