Lecture 4: Connective Tissue Part 2

Question 1

Cartilage is ___, ___ and more ___ than bone.

Answer 1

Stronger, lighter, flexible.

Question 2

What are the three components of cartilage?

Answer 2

1. Cells
2. Fibres
3. Ground Substance

Question 3

What produces the extracellular matrix?

Answer 3

The chrondoblasts and chrondocytes.

Question 4

What structure surrounds cartilage (except articular cartilage)?

Answer 4

The perichondrium which is dense irregular connective tissue.

Question 5

How does cartilage gain nutrients considering is lacks all vessels?

Answer 5

Through diffusion.

Question 6

What are the two cell types found in cartilage?

Answer 6

Chondroblasts (stem cells) and chrondocytes (mature blasts).

Question 7

Where are chrondocytes located and what is their function?

Answer 7

Located in isogenic groups surrounded by ECM. The function is to secrete and maintain the ECM.

Question 8

Where are the chrondoblasts located and what is their function?

Answer 8

Derived from mesenchymal cells in the perichondrium. Their function is to secrete the ECM of cartilage.

Question 9

What are the four layers in this structure of cartilage?

Answer 9

Perichondrium, cartilage, loose connective tissue, respiratory epithelium (top to bottom).

Question 10

What are the two types of growth patterns of cartilage?

Answer 10

Interstitial and appositional.

Question 11

What is interstitial growth?

Answer 11

The division of chondrocytes by mitosis to make more matrix.

Question 12

What is appositional growth?

Answer 12

Where mesenchymal cells in the perichondrium differentiate into chondroblasts.

Question 13

What is the perichondrium?

Answer 13

The dense irregular tissue that surrounds cartilage. (All but articular cartilage).

Question 14

What are the cells of the perichondrium called?

Answer 14

Condrogenic cells.

Question 15

What are the three types of cartilage?

Answer 15

1. Hyaline cartilage
2. Fibrocartilage
3. Elastic cartilage

All contain chondrocytes but differences arise in the ECM.

Question 16

What is the most common type of cartilage and what is its main function?

Answer 16

The function of hyaline cartilage is to resist compressive forces due to high water content.

Question 17

What type of cartilage is this?

Question 18

What type of cartilage is this?

Question 19

What type of cartilage is this? Insert histology of elastic cartilage ppt. pg. 25.

Answer 19

Elastic cartilage.

Question 20

The ECM of elastic cartilage contains ___ and ___.

Answer 20

Collagen (type II) and elastin fibres.

Question 21

Cartilage is avascular and thus gains nutrients via ___ only.

Answer 21

Diffusion.

Question 22

How is cartilage repaired?

Answer 22

The differentiation of cells from the perichondrium.

Question 23

Why is articular cartilage difficult to repair?

Answer 23

There is no perichondrium.

Question 24

What are the three regions of a long bone?

Answer 24

1. Proximal epiphysis
2. Diaphysis
3. Distal epiphysis

Question 25

What are the three components of bone and what gives bones rigidity?

Answer 25

1. Cells 2. Fibres 3. Ground Substance The rigidity is formed from the mineralisation of the ECM.

Question 26

What are the four types of bone cells?

Answer 26

1. Osteoprogenitor cells (stem cells) 2. Osteoblasts (bone forming cells) 3. Osteocytes 4. Osteoclasts

Question 27

What are the three main functions of bone?

Answer 27

1. Support 2. Protection 3. Calcium homeostasis

Question 28

Bones exist in what two forms?

Answer 28

1. Woven (immature) 2. Lamellar (mature) – is compact and spongy

Question 29

Where is the periosteum (tough connective tissue layer) located?

Answer 29

The outermost layer of the bone, surrounding the other structures.

Question 30

What type of immature bone has random organisation of collagen fibres?

Answer 30

Woven bone.

Question 31

What type of bone is dense and organised with osteons and a lateral canal?

Answer 31

Compact bone (fibres and matrix create strength and rigidity).

Question 32

What shape are osteons and where do they run from?

Answer 32

Osteons are cylindrical and run the length of compact bone.

Question 33

What is the function of an osteon?

Answer 33

The function is to provide a canal for blood vessels, nerves and lymphatics while resisting vertical compression.

Question 34

How do blood vessels supply osteons?

Answer 34

Through lateral canals.

Question 35

Where do the arteries come from that supply the bone?

Answer 35

The periosteum.