Lab4 - Bones Flashcards
What are the 5 zones of the epiphyseal plate?
*on the compact bone side
1. Zone of resting cartilage
2. Zone of proliferating cartilage (chondrocytes in hyalin cartilage do mitosis)
3. Zone of hypertrophic cartilage (chondrocytes get larger)
4. Zone of calcified cartilage/Zone of cell death (chondrocytes dye and leave behind a calcified matrix)
5. Zone of ossification/zone of mixed spicules → (calcified matrix replaced with bone) → where osteoprogenitor cells arrive and become osteoblasts, no more chondrocytes
*Osteoblasts secrete bone matrix on calcified cartilage
What is mixed spicules?
Calcified matrix and bone deposited by osteoblasts at the bone surface
What is lamellar vs woven bone classification?
Lamellar → Arranged in sheets (80% within compact bone, 20% within spongy bone)
Woven → Arranged randomly, Growing and developing bones
How can osteoblasts be described?
- Cuboidal
- Eccentrically located nucleus
How can Osteocytes be described?
- Most abundant
- Appear flattened (with projections)
How can osteoclasts be described?
- large round multi-nucleated cells
- Function → resorption of bone
What are the Diaphysis vs Epiphysis of a long bone?
Diaphysis = compact bone surrounding marrow cavity
Epiphyses = Spongy bone within/surrounded of compact bone and cartilage on the joint surfaces (both ends)
What is the Epiphyseal plate?
It is a growth plate of hyaline cartilage at the end of each long bone where the growth takes place
→ Not bone, it is cartilage!!
*Grows mostly during childhood
What are the layers of the periosteum?
→ Outer fibrous layer of dense irregular CT
→ Inner osteogenic layer containing primitive stem cells
What compartement of the bone is the marrow in?
In the medullary cavity
What is the epiphyseal line?
It is an epiphyseal plate that has become ossified (separates epiphysis and diaphysis)
*Formed from the remnant of the epiphyseal plate, when it becomes bone
When epiphyseal plate becomes line, stop growin taller
What are periostal arteries and periostal veins?
They run outide the periosteum,
Connected to haversian canals by Volkmann’s canals
Where do osteocytes sit?
They sit in lacunae
What surrounds the inside of a harvesian canal?
A single layer of osteoblasts → stained purple
How can we differentiate Volkmann and Haversian canals in a tissue slice?
PLAN OF SECTION → they are perpendicular to each other (Harversian will appear as a circle often and Volkmann more as a line-ish)
*They will have red inside them because they have blood vessels
