Cartilage (Grace)

Question 1

Cartilage belongs to what tissue group?

What is the main function of this group?

Answer 1

It is a supporting connective tissue (so is bone)

main functions: supports soft tissues and body weight

Question 2

What are 3 main functions of cartilage?

Answer 2

It provides shock absorption, support and flexibility to areas where the body must withstand deforminty.

Question 3

What is the most common type of cartilage in the body? Why?

Answer 3

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.

Question 4

Where is hyaline cartilage found in the body? (7)

Answer 4

Articular surfaces of long bones
Nose
Trachea
Larynx
Costal cartilage
Fetal skeleton
Epiphyseal plates

Question 5

What are the main cells found in hyaline cartilage? What are groups of these cells called?

Answer 5

Chondrocytes.

Groups are called Isogenous Groups

Question 6

What are the cavities surrounding chondrocytes called?

What surrounds both of these structures in hyaline cartilage tissue?

Answer 6

Lacuna. (potential space)

The extracellylar matrix surrounds the lacuna and chondrocytes.

Question 7

What is the structure of Fibrocartilage?

Answer 7

• 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

Question 9

Where is fibrocartilage found in the body? (3)

Answer 9

ALWAYS associated with dense connective tissue

Intervertebral discs (annulus fibrosus)
Pubic symphysis
Menisci

Question 10

What is the defining structure in Elastic Cartilage?

Where is it found in the body? (4)

Answer 10

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

Question 11

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?

Answer 11

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.

Question 12

What components make up the cartilage matrix? (4)

Answer 12

1. proteoglycans (derived form chondrotin sulfates)
2. COLLAGEN II
3. ground substance (gel-like)
4. Chondrocytes (surrounded by lacunae chambers)

Question 13

What is the vascular structure of cartilage?

Answer 13

1. Avascular (no blood vessels)
   - chondroctyes produce an antiangiogenesis factor (prevents blood vessels from forming)

* Perichondrium provides vascular supply to cartilage*

Question 14

Describe the location, layers and functions of the perichondrium?

Answer 14

Location: surrounds some hyaline and elastic cartilages

1. Outer fiberous layer - dense, irregular CT; contains fibroblasts which produce collagen I fibers; (strength)
2. Inner cellular layer - chondrogenic; contains fibroblasts which produce chondroblasts chondrocytes; small blood vessels: (growth & maintenance)

Question 15

The Chondrocyte.

1. Describe the physical structure
2. What type of collegan is produced and where?
3. how does it produce energy?

Answer 15

1. Cell is round; eccentric (non-medial) nucleus; prominent nucleolus; basophilic cytoplasm.
2. Collagen II fibers are produced on the RER (as is ground substance)
3. Chondroctyes use “anerobic glycolysis” to produce energy.

Question 16

What is “anerobic glycolysis”?

Answer 16

productions of energy in a low-oxygen environment.

• transformation of glucose to pyruvate
• produces 2 ATP : 1 glucose molecule (5% of energy potential)

Question 17

What are 5 components of cartilage ground substance?

Answer 17

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.

Question 18

What are GAGs?

Answer 18

“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.

Question 19

What is the organization of hyaline cartilage?

Answer 19

• 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

Question 20

What enhances & inhibits cartilage matrix growth?

Answer 20

Enhancers: growth hormone, thyroxine, and testosterone

Inhibitors: estradiol and excess cortisone.

Question 21

What is Interstitial Growth?

Why is it important in the fetus & post-partum?

Answer 21

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

Question 22

What are the 2 growth processes of cartilage?

what is involved in both?

Answer 22

Interstitial growth & Appositional growth.

Both involve mitosis & the deposition of additional matrix.

Question 23

What is Appositional Growth?

What type of growth is it responsible for?

Answer 23

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.

Question 24

How is cartilage repaired?

Answer 24

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.

Question 25

What are the functions of Fibrocartilage?

Answer 25

• resist deformation under great stress
• attaching bone to bone
• providing restricted mobility

Question 26

What are the 3 types of cartilage?

What are their MAIN functions?

Answer 26

Hyaline cartilage:
–translucent matrix (looks “glassy”)
–no prominent fibers

function:
Reduces friction in joints

Elastic cartilage:
–tightly packed elastic fibers

function:
Flexible support

Fibrocartilage:
–very dense collagen fibers

function:
Resists compression

Question 27

What are the structural & metabolic difference between cartilage and bone?

Answer 27