Cartilage

Question 1

What is cartilage?

Answer 1

A dense supportive connective tissue that consists of cells (chondrocytes), fibers, and ground substance

Question 2

Is cartilage vascularized?

Answer 2

No, no capillary bed

Question 3

How does the lack of vascularization affect cartilage?

Answer 3

Limits the thickness of cartilage

Thick cartilage has vascular canals

Question 4

What are the types of cartilage?

Answer 4

Hyaline, fibrocartilage, elastic cartilage

Question 5

What are examples of hyaline cartilage?

Answer 5

Developing bones, growth plates, articular surfaces, respiratory tracts

Question 6

What are examples of fibrocartilage?

Answer 6

Intervertebral discs, cardiac skeleton, some tendon/muscle to bone connections

Question 7

What are examples of elastic cartilage?

Answer 7

Epiglottis, pinna

Question 8

What are chondrocytes?

Answer 8

Chondrocytes are mature cells that are within the spaces of the cartilage extracellular matrix

Question 9

Do chondrocytes occur singly or in groups?

Answer 9

Both singly and in isogenous groups

Question 10

What are chondrocytes responsible for?

Answer 10

Production and Maintenance of cartilage

Question 11

What cells differentiate in to chondrocytes?

Answer 11

Mesenchymal cells

Question 12

What do chondrocytes look like?

Answer 12

Round with basophilic nucleus

Question 13

When do mesenchymal cells become chondrocytes?

Answer 13

When mesenchymal cell is surrounded by extracellular matrix

Question 14

What is a lacunae?

Answer 14

The space in the extracellular matrix that is occupied by the chondrocyte

Question 15

Defining characteristics of lacunae

Answer 15

Good contrast between the chondrocyte and the matrix

Chondrocytes usually shrink more than the extracellular matrix

Question 16

Which characteristic is used to easily define cartilage?

Answer 16

Presence of lacunae

Question 17

What is ground substance made of?

Answer 17

Proteoglycan aggregates (made of many GAGs)

Hyaluronic acid is the most important one for binding aggregates

Question 18

Is ground substance hydrophilic?

Answer 18

Yes, proteoglycans absorb 50x their dry weight in interstitial fluid

Question 19

Why is the ground substance resilient?

Answer 19

Negative charge of GAGs repel each other

Question 20

How do chondrocytes receive nutrition?

Answer 20

Nutrients and waste products diffuse through the extracellular matrix

Proteoglycan aggregates hold extracellular fluid which can be squeezed in and out of cartilage

Question 21

Do chondrocytes connect?

Answer 21

No, chondrocytes do not contact each other

Question 22

What is the perichondrium?

Answer 22

dense irregular connective tissue that surrounds cartilage

Question 23

What are the 2 layers of perichondrium?

Answer 23

Inner layer is chondrogenic (cells of inner layer are chondroblasts)

Outer layer is typical fibrous connective tissue

Question 24

Is perichondrium present on articular or fiborcartilaginous cartilage?

Answer 24

No

Question 25

What are the directions of cartilage growth?

Answer 25

Appositional or interstitial

Question 26

What is appositional growth?

Answer 26

New cartilage is deposited on the surface of existing cartilage under the perichondrium Chondroblasts in the inner layer become trapped by their own products and become chondrocytes

Question 27

What is interstitial growth?

Answer 27

Cartilage tissue expands from within the tissue Chondrocytes within the cartilage divide and produce more cartilage

Question 28

What are isogenous groups?

Answer 28

Evidence of interstitial growth Results from division of chondrocytes in the lacunae As the tissue grows, the cells become more separated

Question 29

What type of collagen is present in the extracellular matrix?

Answer 29

Fine collagen fibers (type II) | This gives the extracellular matrix a glassy appearance

Question 30

What color does the ground substance stain?

Answer 30

Basophilic

Question 31

Chondrocytes occur randomly singly or in isogenous groups in hyaline cartilage, what are the exceptions to this?

Answer 31

Growth plates and articular cartilage are more structured

Question 32

What are the zones of articular cartilage?

Answer 32

Superficial zone has flattened chondrocytes and collagen fibers are parallel to the joint surface The middle zone has round lacunae and collagen fibers that arc towards the underlying bone

Question 33

How to tell elastic cartilage from hyaline cartilage?

Answer 33

Elastic fibers will contrast with the ground substance

Question 34

Where is elastic cartilage found?

Answer 34

E- Epiglottis, External Ear, Eustacian tube

Question 35

What type of fibers does fibrocartilage have?

Answer 35

Large collagen fibers to help with tendons and ligaments, intervertebral discs and symphyses

Question 36

How are cells arranged in fibrocartilage?

Answer 36

Rounded cells in lacunae and arranged in rows between collagen fibers

Question 37

How to tell apart fibrocartilage and dense regular connective tissue?

Answer 37

Round cells in lacunae