Histology of Cartilage Flashcards
What is mesenchyme?
embryonic stem cells giving rise to many other tissue types
Why is the role of mesenchyme in cartilage formation?
it gives rise to all adult CT, specifically producing chondroblasts
3 main components of cartilage
- cells
- ECM
- Perichondrium
Cell types in cartilage
- chondroblasts
2. chondrocytes
Chondroblasts
secrete ECM, come from mesenchymal stem cells
Chondrocytes
maintain/produce ECM, come from chondroblasts, reside in lacunae
What percent of cartilage is formed by ECM?
95%+
Perichondrium
DCT capsule, covers some cartilages, contains BVs, nerves, fibroblasts, type I collagen, essential for growth/maintenance of some cartilage
Mechanisms of cartilage growth
- Appositional growth
2. Interstitial growth
Appositional growth
addition to an existing surface, generation of new chondroblasts
Interstitial growth
internal expansion, proliferation of chondrocytes and formation of isogenous groups
3 types of cartilage
- Hyaline cartilage
- Elastic Cartilage
- Fibrocartilage
ECM component of Hyaline cartilage
75% water (allows for diffusion), proteoglycans, hyaluronic acid, type II collagen
Location of Hyaline cartilage
articular surfaces, nose, larynx, tracheal rings, epiphyseal plates, fetal bone models
Appearance of Hyaline cartilage
fresh: blue/white
histo: basophilic matrix, indistinguishable collagen fibers with H+E stain
Territorial matrix
area directly surrounding isogenous groups, darker
Interterritorial matrix
space between territorial matrix, lighter
ECM component of Elastic cartilage
same as Hyaline, plus elastic fibers (more bendy than Hyaline)
Location of Elastic cartilage
auricle, auditory canal, auditory tube, epiglottis
Perichondrium of Hyaline cartilage
present
Perichondrium of Elastic cartilage
present
Appearance of Elastic cartilage
fresh: yellowish
histo: prominent elastic fibers with special stain
ECM component of Fibrocartilage
type I collagen (like DCT), less proteoglycans than other cartilage (vvery very strong)
Location of Fibrocartilage
intervertebral discs, pubic symphysis, major tendon-bone anchorages (areas that undergo pulling forces)
Perichondrium of Fibrocartilage
absent
Appearance of Fibrocartilage
looks like cross between DCT and hyaline cartilage, chondrocytes arranged in long rows separated by coarse collagen fibers, acidophilic matrix
