Bone Structure and Function

Question 1

Difference between bones and cartilage in respect to nerves.

Answer 1

Bones are rich in nerves whereas cartilage has no nerves

Question 2

What is the area between the diaphysis and epiphysis called?

Answer 2

Metaphysis

Question 3

What feeds osteons with nutrients?

Answer 3

Haversion canals

Question 4

What are two types of bone?

Answer 4

Spongy and compact

Question 5

What are three types of cartilage?

Answer 5

Hyaline
Fibro
Elastic

Question 6

What type of growth pattern do bone and cartilage have respectively?

Answer 6

Bidirectional

Unidirectional

Question 7

What is bone matrix made up of?

Answer 7

Calcium and potassium-based hydroxyapatite

Question 8

What is the organic proteins found in bone and cartilage respectively?

Answer 8

Ossein

Chondrin

Question 9

What is the difference between bone and cartilage matrix?

Answer 9

Bone is inorganic and organic

Cartilage is only organic

Question 10

All cells in bone originate from mesenchymal stem cells except for?

Answer 10

Osteoclasts

Question 11

Where do osteoclasts arise from?

Answer 11

Granulocyte/monocyte progenitor cell

Question 12

How are osteoclasts formed?

Answer 12

Granulocyte/monocyte progenitor cell -> inactive osteoclast -> active osteoclasts (multiple come together multi-nucleated)

Question 13

Where do osteocytes come from?

Answer 13

Osteoblasts that have become trapped in the matrix they formed

Question 14

What role do osteocytes play in bone maintenance?

Answer 14

Absorb and place bone matrix
Sense density of bone
Stress sensors
Maintain calcium ion level in blood

Question 15

Describe the outer layer of periosteum

Answer 15

Thick, tough, highly vascular irregular dense CT

Question 16

Describe inner layer of periosteum

Answer 16

Thin osteogenic layer with osteoprogenitor cells

Question 17

What is the endosteum?

Answer 17

Single layer of flat osteoprogenitor cells that lines all internal bone surfaces (marrow cavities)

Question 18

What bones are formed by intramembranous ossification?

Answer 18

Skull, mandible, and clavicle

Question 19

What are the steps in intramembranous ossification?

Answer 19

Primary ossification centers for when osteoblasts surround growing vessels to form spicule islands and fuse into spongy bone trabeculae

Question 20

What is unique about intramembranous ossification?

Answer 20

Bone is formed by replacing primitive mesenchymal CT

Question 21

What does intramembranous ossification look like?

Answer 21

Spongy bone between two compact bone plates

Question 22

What are steps in primary endochondral ossification?

Answer 22

1. Periosteal Collar laid down by osteoblasts in perichondrium
2. Chondrocytes destroyed and cartilage matrix calcified to form spicules in diaphysis
3. Osteogenic bud (capillaries & osteoprogenitor cells) invades spaces left by chondrocytes
4. Osteoprogenitor cells osteoblasts begin to lay down bone matrix

Question 23

Red marrow function

Answer 23

Hematopoiesis

At birth all is red

Question 24

Yellow marrow function

Answer 24

Adipocytes in medullary cavities

Yellow-> red marrow in blood loss

Question 25

What is aggrecan made of?

Answer 25

Proteoglycans linked to hyaluronic acid

Question 26

Characteristics of territorial matrix

Answer 26

Rich in GAG and poor in collagen, surrounds each chondrocyte and stains blue

Question 27

Characteristics of interterritorial matrix

Answer 27

Rich in collagen fibers

Question 28

What type of collagen is found in all three cartilage?

Answer 28

Type II collagen

Question 29

What collagen is found in fibrocartilage?

Answer 29

Type I collagen

Question 30

What happens early in osteoarthritis?

Answer 30

Disruption of matrix-molecular framework increasing water content and decreasing PGs
Thickening of subchondral bone

Question 31

What would happen to bone without mineral?

Answer 31

It would be flexible

Question 32

What would happen to bone without collagen?

Answer 32

It would shatter