FOM 3.1.3 Flashcards
What are is this, what is it stained with and what are the arrows pointing at?
This is hyaline cartilage stained with H and E. The arrows are pointing at chondrocytes in their lacunae.
How does hyaline cartilage accomplish its role as a shock absorber?
Hyaline cartilage functions like a shock absorber or biomechanical spring: solvation water is bound water which interacts with the negatively charged proteoglycans and is squeezed out of cartilage on compression and returns and binds during decompression.
What is the rigidity of the hyaline cartilage dependent on?
Rigidity is dependent on the electrostatic interactions between type II collagen fibrils and the GAGs comprising the proteoglycans resulting in a cross-linked matrix.
What is responsible for rigidity of cartilage?
Type II collagen binding to the proteoglycan aggregate
How is the protein portion of the GAG synthesized and processed?
It is synthesized in the ER and sugars are added to it in the golgi
What is a main differenct between cartilage and bone andhow does this affect the way nutrients are delivered to it?
Cartilage lacks blood vessels, it is AVASCULAR which requires that nutrients and waste seep through the matrix by diffusion.
Deposition of lime salts in the form of hydroxyapatite crystals does what for bone?
It prevents the diffusion of metabolites and prevents interstitial growth, both of these occur in the cartilage
What is are the two types of bone?
Compact bone: dense without cavities
Cancellous (trabecular) bone: 3-dimensional lattice of branching bony spicules, forming trabeculae around marrow spaces
What are the arrows in this picture pointing to?
The top arrows are pointing to cancellous bone and the bottom arrows are pointing to compact bone
What does each of the numbers correspond to?
- Compact bone
- Periosteum
- Marrow cavities
- Trabecular bone
- Epiphysis
- Metaphysis
- Diaphysis
What is the composition of the bone matrix?
Organic Matrix 35% - consisting of 85-90% type I collagen, proteins, glycoproteins
Inorganic Salts - Hydroxyapatite crystals
What is an osteoprogenitor cell and what is its role?
Pluripotent stem cell from mesenchyme. Capable of differentiating into osteogenic cells, osteoblasts. Found in the periosteum and endosteum as bone lining cells in non-growing regions and differentiate into osteoblast following a fracture
What are osteoblasts and what are their role?
These cells synthesize and secrete organic matrix of the bone: types I collagen, non-collagenous protein and alkaline phosphatase.
What are osteocytes?
Osteoblasts that have trapped themselves in calcified matrix
What is an osteoclast?
These are giant multinucleated cells that are derived from monocytes. Produce an acidic environment ideal for the dissolution of bone matrix. These are also said to have a ruffled border