Lecture 4 - Bone Tissue Flashcards
What is bone?
Bone is a living tissue that has cells, as well as a calcified extra cellular matrix. Bone can respond to the forces coming to your body.
What sort of tissue is bone?
Bone is a hard connective tissue. It supports other tissues/organs and maintains form.
What are the two extra cellular components of bone?
- Organic (all connective tissue made and also proteins)
2. Inorganic (hard aspect of bone)
What are extracellular components?
Anything in a tissue that is not a cell.
If bone is organic what are its properties?
- Collagen (protein) exists in fibers that run through the mineral part of the bone
- Ground substance (proteoglycans)
- Function = resists tension
If bone is inorganic what is its properties?
- Hydroxyapatite + other Ca minerals
What is a mineral component?
The thing that makes your bones resistant to compression.
What would happen to your bones if you soaked them in acid?
It would take out the inorganic part of the bone and make the bone loose and floppy and wouldn’t be able to hold weight and have a posture
The cellular component of bone makes up what percentage of bone by weight?
2%
What are the four types of cells in bone?
- Osteogenic
- Osteoblasts
- Osteocytes
- Osteoclasts
Osteogenic cells are :
Stem cells that produce osteoblasts
Osteoblast cells are :
MAKERS : produce new bone matrix
Osteocyte cells are :
MAINTAINERS : recycle protein and minerals from matrix
Osteoclast cells are :
DESTROYERS - remove bone matrix
What is the gross structure of compact bone?
Osteon structure. Organized structure around osteons
What is the gross structure of cancellous bone?
Trabecular structure. Laced and branching off each other
Bone macroscopically is :
Outer surfaces seem dense and impenetrable (periosteum)
Foramina/holes for blood supply - nerve and nutrient supply
Bone microscopically is :
Made up of circumferential lamellar and units called osteons
What are osteons?
Osteons are cylindrical structures that contain a mineral matrix and living osteocytes connected by canaliculi, which transports blood. Each osteon consists of lamellar, which are layers of compact matrix that surround a central canal.
Within an osteon, what holds blood vessel and nerves?
Central canal
Within an osteon, a series of cylinders formed of ECM around the central canal are called…
Concentric lamellae
The canaliculi…..
Channels for osteocytes through ECM and runs through the central canal to lamellae.
The Lacunae is…
Lakes for osteocytes
Why are cancellous bones trabecular?
The organization of trabecular resists force from multiple directions. Direct force from the body weight in single direction down the shaft. Trabecular helps spread out weight to the entire bone instead of in one specific place which is why cancellous bone is weight resistant.
