Cartilage/Bone Flashcards
Chondroblasts
Chondrogenic cells give rise to chondroblasts
Synthesize cartilage matrix
Responsible for external growth of cartilage
What type of growth is chondroblasts responsible for?
Appositional growth
Chondrocytes
Are matured chondroblasts located in the lacunae and surrounded by matrix
-Located deeper to the chondroblasts and are more spherical
Isogenous groups
Groups of 4-8 chondrocytes that are suggestive of internal growth (interstitial growth)
Interstitial growth
Internal growth of chondrocytes
Chondroclast
Originates from monocytes
Help to remodel the cartilage
What type of collage composes the extracellular matrix?
Type II collagen (Hyaline cartilage)
Capsular matrix
Matrix adjacent to the chondrocyte
Territorial matrix (TM)
Matrix found around isogenous groups
Interterritorial matrix (IM)
Matrix in-between isogenous groups
Territorial Matrix composition
Randomly arranged network of type II collagen fibrils with smaller quantities of type IX collagen
-Lower concentration of sulfated proteoglycans
-Less basophilic than the capsular matrix
Perichondrium layers
- Outer fibrous layer contains fibroblasts: synthesize collagen type I and matrix
- Inner cellular layer/chondrogenic layer: chondrogenic cells
Is cartilage avascular or vascular?
Avascular: Nutrients are supplied by vessels from perichondrium by diffusion or from the synovial fluid at the articular surfaces
Inner cellular layer (CL) of perichondrium
Source of chondroblasts
Outer fibrous layer (FL)
- Contains fibroblasts
- Type I collagen
- Blood vessels
Hyaline cartilage collagen type
Type 2: Glassy like appearance
Elastic cartilage collagen type
Type 2 collagen with elastic fibers
Fibrocartilage collagen type
Mix of type 1 and type 2 cartilage lacks a perichondrium
Appositional growth
The process that forms new cartilage at the surface of an existing cartilage
Type of cell that is metabolically active and multifunctional that respond to mechanical forces applied to the bone.
Osteocytes
Key regulator of calcium and phosphate levels in the extracellular fluid
Parathyroid hormone
PTH acts to:
Raise low blood blood calcium levels to normal
PTH is secreted by
the principal (chief) cells of the parathyroid glands
Calcitonin acts on:
The bone to lower elevated blood calcium levels to normal
Calcitonin is secreted by
The parafollicular cells of the thyroid gland.
