Cartilage (Grace) Flashcards
Cartilage belongs to what tissue group?
What is the main function of this group?
It is a supporting connective tissue (so is bone)
main functions: supports soft tissues and body weight
What are 3 main functions of cartilage?
It provides shock absorption, support and flexibility to areas where the body must withstand deforminty.
What is the most common type of cartilage in the body? Why?
Hyaline Cartilage is the most common. It provided the primary supportive structure for the body during development until much of it was replaced by bone.
Where is hyaline cartilage found in the body? (7)
Articular surfaces of long bones
Nose
Trachea
Larynx
Costal cartilage
Fetal skeleton
Epiphyseal plates
What are the main cells found in hyaline cartilage? What are groups of these cells called?
Chondrocytes.
Groups are called Isogenous Groups
What are the cavities surrounding chondrocytes called?
What surrounds both of these structures in hyaline cartilage tissue?
Lacuna. (potential space)
The extracellylar matrix surrounds the lacuna and chondrocytes.
What is the structure of Fibrocartilage?
- It has numerous coarse, readily visible fibers arranged in irregular bundles between large chondrocytes.
(intermediate in character between hyaline cartilage and dense connective tissue)
- Abundant TYPE I collagen fibers; (at low magnification, it resembles dense connective tissue) *
- ground substance contains equal amounts of dermatan sulfate & chondroitin sulfate.
- capsular matrix resembles that of hyaline cartilage and contains some TYPE II collagen
- chondrocytes are distributed in columnar isogenous groups (b/t the densely packed type I collagen bundles)
- No perichondrium
Where is fibrocartilage found in the body? (3)
ALWAYS associated with dense connective tissue
Intervertebral discs (annulus fibrosus)
Pubic symphysis
Menisci
What is the defining structure in Elastic Cartilage?
Where is it found in the body? (4)
It contains numerous elastic fibers.
- contains TYPE II collagen-
It is yellow when fresh and is more flexible than hyaline.
Has a perichondrium.
It is found in the:
external ear
the external auditory canals and auditory tubes
the epiglottis
the corniculate and cuneiform cartilages of the larynx
What type of cartilege is present in the synovial joints of long bones?
Where is it located and how does it contribute to the joint?
Hyaline cartilage creates the articulating surface at the end of long bones. The synovial membrane is located between the 2 articulating ends, which helps reduce firstion at the joint.
What components make up the cartilage matrix? (4)
- proteoglycans (derived form chondrotin sulfates)
- COLLAGEN II
- ground substance (gel-like)
- Chondrocytes (surrounded by lacunae chambers)
What is the vascular structure of cartilage?
- Avascular (no blood vessels)
- chondroctyes produce an antiangiogenesis factor (prevents blood vessels from forming)
* Perichondrium provides vascular supply to cartilage*
Describe the location, layers and functions of the perichondrium?
Location: surrounds some hyaline and elastic cartilages
- Outer fiberous layer - dense, irregular CT; contains fibroblasts which produce collagen I fibers; (strength)
- Inner cellular layer - chondrogenic; contains fibroblasts which produce chondroblasts chondrocytes; small blood vessels: (growth & maintenance)
The Chondrocyte.
- Describe the physical structure
- What type of collegan is produced and where?
- how does it produce energy?
- Cell is round; eccentric (non-medial) nucleus; prominent nucleolus; basophilic cytoplasm.
- Collagen II fibers are produced on the RER (as is ground substance)
- Chondroctyes use “anerobic glycolysis” to produce energy.
What is “anerobic glycolysis”?
productions of energy in a low-oxygen environment.
- transformation of glucose to pyruvate
- produces 2 ATP : 1 glucose molecule (5% of energy potential)
What are 5 components of cartilage ground substance?
1.GAGs (Glycosaminoglycans)
- which are mostly chondroitin sulfates & hyaluronan (also include smaller amounts of keratin sulfate and heparan sulfate)
2. Proteoglycans
- which are core proteins with covalently bound GAG side chains.
**3.Proteoglycan aggregates **
- which are proteoglycans noncovalently linked to long chains of hyaluronan by link protein.
4.Glycoproteins
- including link protein, fibronectin, and chondronectin, which attach various matrix components to one another and cells to the matrix.
5.Tissue fluid
- an ultrafiltrate of blood plasma.
What are GAGs?
“Glycosaminoglycans”
(aka mucopolysaccharides)
long unbranched polysaccharides –> repeating disaccharide unit.
The repeating unit (except for keratan) consists of an amino sugar along with a uronic sugar or galactose.
Glycosaminoglycans are highly polar and attract water. They are therefore useful to the body as a lubricant or as a shock absorber.
What is the organization of hyaline cartilage?
- extensive cross-linking of components (creates firmness)
- link proteins attach protoglycan proteins to long, hyaluronan chains (Proteoglycan Aggregates)
- GAG side chains of aggregate associates w. TYPE II collagen
What enhances & inhibits cartilage matrix growth?
Enhancers: growth hormone, thyroxine, and testosterone
Inhibitors: estradiol and excess cortisone.
What is Interstitial Growth?
Why is it important in the fetus & post-partum?
The division of existing chondrocytes and gives rise to theisogenous groups.
Fetal importance: forms the fetal skeleton
Post-Partum: continues in the epiphyseal plates and articular cartilages
What are the 2 growth processes of cartilage?
what is involved in both?
Interstitial growth & Appositional growth.
Both involve mitosis & the deposition of additional matrix.
What is Appositional Growth?
What type of growth is it responsible for?
The differentiation of chondroblasts and stem cells into immature chondrocytes on the perichondrium’s inner surface + deposition of new matrix.
Responsible for increases in the girth of the cartilage masses.
How is cartilage repaired?
It involves invasion of the breach by mesenchymal stem cells from the perichondrium, which subsequently differentiate into chondrocytes. If the gap is large, a dense connective tissue scar may form.
What are the functions of Fibrocartilage?
- resist deformation under great stress
- attaching bone to bone
- providing restricted mobility
