Skeletal System Flashcards
- Development of Cartilage Model
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
- Growth of Cartilage Model
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
- Development of Primary Ossification Center
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
- Formation of Medullary Cavity
Osteoclasts are brought in to the center of the model and break down spongy bone to create hollow medullary cavity
- Development of Secondary Ossification Center
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
6 Growth in Length
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
5 types of tissues that make up skeletal system
Epithelial
Nervous
Cartilage
Adipose
Blood
5 Functions of bone
Attachment point for muscles
Protection
Blood cell production
Energy storage - adipose tissue (yellow bone marrow)
Mineral storage - calcium and phosphate
What is the periosteum?
Superficial membrane covering bone
Does NOT cover cartilage
What is the endosteum?
Lining of the marrow cavity
What is an Osteoprogenitor cell?
Unspecialized bone stem cell
What is an osteocyte?
Mature bone cell that maintains bone tissue
What does an osteoclast do?
Breaks down bone tissue (remodels)