Cartilage

Question 1

Cartilage Characteristics

Answer 1

1. Amorphous ECM predominates over fibrous ECM
2. Rich in proteoglycans
3. Functions in support and flexibility for sliding of joints, as a shock absorber and growth of long bones
4. Presence declines from fetus to adult

Question 2

Perichondrial Fibroblasts

Answer 2

• in the Perichondrium

- These give rise to chondroblasts which mature into chondrocytes

Question 3

Chondroblast

Answer 3

• Arise from Perichondrial Fibroblasts

- Do not have a territorial matrix

Question 4

Chondrocyte

Answer 4

• Contains territorial matrix

-

Question 5

Chondroclasts

Answer 5

• Reabsorb cartilage
• related to osteoclasts
• Derive from monocytes and have a phagocytic role

Question 6

Proteoglycans

Answer 6

• Major Amorphous Component

- Hyaluronic Acid Filaments (hydrophillic)

Question 7

Papain

Answer 7

• Hydolyzes the proteoglycan moiety of the cartilage matrix

Question 8

Type II Collagen

Answer 8

• Fibrous Component
• Present in all types of cartilage
• Covered over with GAG and proteoglycans
• Type II collagen deposition is associated with differentiation and maturation of cartilage

Question 9

Non Vasularity of Cartilage

Answer 9

1. No Blood supply - channels form fracture planes
2. Diffusion is rate limiting to thickness of cartilage
3. Damage/ loss of cartilage is difficult to regenerate

Question 10

Perichondrium

Answer 10

• All cartilage possess Perichondrium EXCEPT epiphyseal growth plate, fibro and articular cartilage
• Essential for appositional growth
• Provides nutrients
• Sox transcription factors induce differentiation into chondroblast (Sox 9)

Question 11

Appositional Growth

Answer 11

• occurs by differentiation of perichondrial fibroblasts into chondroblasts and chondrocytes

Question 12

Interstitial growth

Answer 12

• occurs by mitosis of existing chondroblasts and chondrocytes
• Occurs in cartilage that lack a perichondrium
• Somatotropin (GH) from anterior pituitary stimulates somatomedin C from liver that stimulates mitosis of chondroblasts and chondrocytes

Question 13

Isogenic nests

Answer 13

• Form by interstitial growth
• Two or more chondroblasts or chondrocytes together.
• Can occur in mature cartilage

Question 14

Osteoarthritis

Answer 14

• Damage of cartilage covering articular surfaces (joints)

Question 15

Hyaline Cartilage

Answer 15

• Contains: Type II collagen, basophilic matrix, and chondrocytes usually arranged in groups
• Prichondrium is present in most places EXCEPT Articular Cartilages and epiphyses
• Located: articular ends of long bones, nose, larynx, trachea, bronci, ventral ends of ribs

Question 16

Elastic Cartilage

Answer 16

• Contains: Type II collagen, and elastic fibers
• Perichondrium is present
• Located: Pinna of ear, walls of auditory canal, auditory tube, epiglottis, Cuneiform cartilage of larynx

Question 17

Fibrocartilage

Answer 17

• Contains: Type I and II collage, acidophilic matrix, condroxytes arranged in PARALLEL rows between bundles of collagen
• Perichondrium absent: Interstitial growth
• Located: intervertebral disks, articular disks, pubic symphysis, insertion of some tendons
• Always associated with dense regular collagenous connective tissue or hyaline cartilage