Cartilage Flashcards
Why do cartilage grafts not have to be donor matched?
The perichondrium (seen in hyaline & elastic cartilage) is an immunoprivelaged area, which means that no antibodies can move into this area due to their size.
List the five features of hyaline cartilage.
- Ridgid & tough
- Compressible (resists compression)
- Has perichondrium
- Little repairative capacity
- Avascular & anuerogenic
What are the locations of hyaline cartilage?
Fetal skeleton, ribs, larynx, tracheal & bronchial rings, nose, and articular surfaces of bones.
List four features of elastic cartilage.
- ridgid BUT FLEXIBLE
- Has perichondrium
- undergoes perichondrial repair
- Avascular and anuerogenic
What are four locations of elastic cartilage?
- Larynx
- External Ear
- Auditory Tube
- Epiglottis
List seven features of fibrocartilage.
- No perichondrium
- Looks like dense connective tissue, but has lacunae
- Mostly type I collagen (for strength), but also has some type II collagen
- Some synnovial nutrients
- Some innervation
- Some repairative capacity
- Very few isogenous groups
List four locations to find fibrocartilage.
- Intervertebral disks (annulus is 100% fibrocartilage, nuclues is fibrocartilage on its edges, mucoid like in the center)
- Meniscuses (varying levels of vasculature, mean varying repairative capacity)
- Symphis Pubis
- Ligamentum of femur
Describe the ground substance of hyaline and elastic cartilage.
Hylauronic acid (HUA) is th backbone of the matrix
The proteoglycan complex is attached to the HAU backbone, it is composed of:
Aggrecan is a core protein bound to HUA via link proteins
GAG’s (e.g. keratin sulfate & chondroitine) bind to the aggrecan
Explain compressive loading force of hyaline cartliage.
The proteoglycan complex is the functional unit of resistance to compression by acting as a water sponge.
The GAG’s, which are anionic, bind H20 and cations (when uncompressed). This leads to expansion of cartilage, but expansion is limited by the collagen type II fibers.
When compression occurs, water is forced out until eequilibrium is reached. Once the load is released the water comes backs in.
In regards to age, what happens to compressibility of the hyaline cartliage?
As you age, less proteoglycan complexes are produced by the chondrocytes to replaced the enyzmatically degraded complexes. So the load capacity would decrease.
Distinguish interstitial and appositional growth
Interstitial (expands from within - bone length) and can only happen in cartilage, while appositional (adds to the surface - bone width) is able to occur in both.
Interstitial cartilage growth for bone length stops in endochondral cartilage after puberty
In adults, the perichondrium has a layer of flattened (chondrogenic layer) of cells that could become chondroblasts and continue appositional growth.
Explain the repair of meniscus relative to its blood supply.
Red part, which is well vascularized, can repair easily.
Red-White part, is less vascularized, and may heal.
White part, your out of luck.
What is osteoarthritis?
Thinning of fibrocartilage until it is bone-on-bone.
This may hurt.
Don’t be a fat old athletic woman who had a knee replacement.