Microscopic Anatomy of Long/Compact Bone Flashcards
What is the Haversian system or osteon?
- Repeating structural unit of compact bone.
- Elongated cylinder parallel to the long axis of the bone
What is the Lamella?
The lamella is each matrix tube in an osteon
* Weight-bearing, column-like matrix tubes composed mostly of collagen
* Looks similar to the rings inside of a tree trunk
Circumferential
- Just deep to the periosteum & just superficial to the endosteum.
- Extend around the entire circumference of the diaphysis
- Resists twisting of the long bone
Central/Haversian Canal
- Runs through the core of each osteon/Haversian canal
- Contains blood vessels and nerves
Volkmann’s Canal
- Lie at right angles to the long axis of the bone.
- Connect the blood & nerve supply of the periosteum to these in the the central canals of the medullary cavity.
- Lined with endosteum.
Sharpey’s Fibers
- What the periosteum is secured by
- Tuffs of collagen fibers that extend from fibrous layer into bone matrix.
Osteocytes
Mature bone cell
Lacunae
- Small cavities in bone that contain osteocytes
- Lacunae in bone are occupied by cells
Canaliculi
Hair-like canals connect lacunae to each other and central canal.
Which way does the canaliculi run?
It runs parallel to the long axis of the bone.
What does the canaliculi connect to?
The canaliculi connect to each other (other lacuna) and other canals
Why does the canaliculi connect?
The canaliculi connect cause they need blood and nutrients.
What makes up the periosteum?
Dense irregular tissue
What does the periosteum do?
The periosteum helps connect tendons to bone.
What do the Sharpey’s fibers do?
The Sharpey’s fibers secure the periosteum to the bone.
