Cartilage

Question 1

Main types of collagen

Answer 1

Type I, II, III and IV

Question 2

Type I collagen

Answer 2

Most abundant, widely distributed

Question 3

Type II collagen

Answer 3

• Hyaline and elastic cartilage

- Fibres thinner than type I

Question 4

Type III collagen

Answer 4

Reticular fibres

Question 5

Type IV collagen

Answer 5

• Found in the basal lamina

- Does not form fibrils

Question 6

What type of collagen is found in dense regular and irregular connective tissue

Answer 6

Type I

Question 7

Where is the basal lamina

Answer 7

Between the epithelia and underlying supporting connective tissue

Question 8

What is the function of the basal lamina

Answer 8

A selective barrier to the passage of materials between the epithelium and supporting tissue

Question 9

What is the basal lamina involved in the control of

Answer 9

Epithelia growth and differentiation

Question 10

What is the basal lamina composed of

Answer 10

GAGs, type IV collagen and glycoproteins

Question 11

What other disaccharide polymer are many proteoglycans non convalently linked to

Answer 11

Hyaluronan

Question 12

What stabilises the interaction between proteoglycans and hyaluronan

Answer 12

Link proteins

Question 13

Describe cartilage

Answer 13

• Semi-rigid connective tissue

- Consists of scattered cells surrounded by amorphous appearing extracellular matrix

Question 14

Composition of extracellular matrix of cartilage

Answer 14

Contains type II collagen which provides mechanical stability and GAGs which resist deformation by compression

Question 15

Cartilage formation

Answer 15

• Differentiation of primitive stellate mesenchymal cells into chondroblasts
• These cells proliferate and aggregates of cells grow and begin to synthesis ground substance and fibrous extracellular material
• Cells mature into chondryocytes and these maintain integrity of cells

Question 16

How dos cartilage get its nutrition

Answer 16

Through diffusion of metabolites

Question 17

What are the cells found within cartilage called

Answer 17

Chrondrocytes

Question 18

Characteristics of chondrocytes

Answer 18

• Live in the lacuna
• Vary in shape
• Flattened near the edge of cartilage
• Rounded near the centre
• Secrete and maintain extracellular matrix

Question 19

What happens if vascular supply around cartilage is disrupted

Answer 19

The cells die, blood vessels invade the matrix and the matrix is phagocytosed and replaced by scar tissue

Question 20

Composition of EMC

Answer 20

75% water and 25% organic materials

Question 21

What is the organic material made from

Answer 21

60% type II collagen and 40% proteoglycan aggregates

Question 22

Important glycoprotein in the cartilage matrix

Answer 22

Chondronectin

Question 23

Function of chondronectin

Answer 23

Promotes the adherence of chondrocytes to the matrix of collagen

Question 24

The matrix in the area around the chondrocyes is

Answer 24

Particularly high in proteoglycans and is known as the territorial matrix

Question 25

Matrix at a distance from chundrocytes

Answer 25

Has fewer proteoglycans and is known as the interterritorial matrix

Question 26

Connective tissue that surrounds the cartilage

Answer 26

Perichondrium

Question 27

Layers of the perichondrium

Answer 27

Outer fibrous layer of dense connective tissue and an inner chondrogenic layer which provides now chondroblasts to the adjacnt cartilage

Question 28

What does the perichondrium contain

Answer 28

Blood vessels that supply nutrients to the whole of the avascular cartilage

Question 29

How does cartilage grow

Answer 29

Appositional growth at the edge and interstital growth with the matrix

Question 30

What are the types of cartilage

Answer 30

Hyaline cartilage, elastic cartilage and fibrocartilage

Question 31

Hyaline cartilage

Answer 31

Blue-white in colour and translucent. Most common form

Question 32

Elastic cartilage

Answer 32

Light yellow in colour. Addition of elastic fibres makes it flexible

Question 33

Fibrocartilage

Answer 33

White in colour. Hybrid between the other two. Has bands of densely packed type I collagen interleaved with rows of chondrocytes surrounded by small amounts of cartilaginous ECM

Question 34

Where is hyaline cartilage found

Answer 34

Articular surfaces, tracheal rings, costal cartilage, epiphyseal growth plates and the precursor to bone in the foetus

Question 35

What type of cartilage is found at a synovial joint

Answer 35

Hyaline cartilage

Question 36

Where is elastic cartilage found

Answer 36

Pinna of the ear, epiglottis and auditory tube

Question 37

Where is fibrocartilage found

Answer 37

Intervertebral discs, where the tendon inserts into the bone (enthesis) and pubic symphysis

Question 38

What effect does age have on cartilage

Answer 38

Chondrocytes from older animal produce shorter proteoglycans which may lead to lessened ability to attract water molecules and decreased resistance to compression = damage of articular cartilage and osteoarthritis

Question 39

Characteristics of cartilage

Answer 39

- Deformable - Permeable - Appositional and interstitial growth - Cells in the matrix nourished through diffusion