Histology of Cartilage and Bone

Question 1

What do mesenchymal condensations do?

Answer 1

Generate cartilage and bone

Question 2

Mesenchymal condensations in the embryo predict the location of the future

Answer 2

Skeletal system

Question 3

Mesenchymal condensations can generate cartilage or bone. What determines their fate?

Answer 3

Proximity to vascularity

Question 4

Condensations that arise in avascular parts of the embryo form

Answer 4

Cartilage

Question 5

Condensations that arise in vascular parts of the embryo form

Answer 5

Bone

Question 6

What is a more likely fate, that condensations form cartilage or bone?

Answer 6

Cartilage

Question 7

Some embryonic cartilage remains cartilage, but most is transiently replaced by

Answer 7

Bone (does not become bone though)

Question 8

Cells of condensation give rise to a type of cell that begins to make the ECM, called

Answer 8

Chondroblasts

Question 9

Chondroblasts that get trapped in the ECM are called

Answer 9

Chondrocytes

Question 10

Forms outer border of most cartilage

-Generates new chondroblasts around the perimeter of the forming cartilage

Answer 10

Perichondrium

Question 11

New chondroblasts generated by perichondrium lead to appositional growth around the

Answer 11

Perimeter

Question 12

What are the two distinct layers of the perichondrium?

Answer 12

1. ) Fibroblastic (outermost layer)

2. ) Chondrogenic

Question 13

Chondrocytes retain the ability to divide and generate

-bone can’t do this

Answer 13

Isogenous groups (clusters)

Question 14

Grows from within (interstitial) and without (appositional)

Answer 14

Cartilage

Question 15

Avascular and contains chondrocytes in lacunae

Answer 15

Cartilage

Question 16

Cartilage is made up of which type of collagen?

Answer 16

Type II

Question 17

What are the three types of cartilage?

Answer 17

Hyaline, Elastic, and Fibro

Question 18

Hyaline cartilage is located in the

Answer 18

Nasal, laryngeal, tracheal, and articular regions

Question 19

Articular hyaline cartilage has no

Answer 19

Perichondrium

Question 20

Where is elastic cartilage found?

Answer 20

Ear, eustacian, and eppiglottis

Question 21

A special feature of elastic cartilage is that it contains

Answer 21

Elastic fibers (requires a special stain)

Question 22

Where is fibrocartilage located?

Answer 22

Symphyses, intervertebral disks, and menisci

Question 23

Fibro cartilage is intermixxed with

Answer 23

Dense CT (no perichondrium)

Question 24

Chondrocytes are secretory cells and are distinguished by

Answer 24

Lots of RER and prominent golgi

Question 25

Stained with basophilic staining and is located right around the edge of chondrocytes

Answer 25

Territorial matrix

Question 26

Acidophilic staining in the area between chondrocytes

Answer 26

Interterritorial matrix

Question 27

Caps the bone at moveable joints

Answer 27

Articular cartilage

Question 28

Articular cartilage is susceptible to osteoarthritis because it lacks a -the reason it is ill equipped to initiate repair

Answer 28

Perichondrium

Question 29

Erosion of the articular cartilage in osteoarthritis results in diminution or disappearance of the

Answer 29

Joint space of X-Ray

Question 30

Made up of a delicate synovial inner layer and a tough fibrous outer layer

Answer 30

Joint capsule

Question 31

Joints are discontinuous epitheliod intima with no tight junctions or a basement membrane. They are leaky and are comprised of

Answer 31

Loose CT and many vessels

Question 32

Causes influx of immune cells into the synovium, which results in destruction of the joint

Answer 32

Rheumatoid arthritis

Question 33

Is radiolucent, i.e. why we can't see ears on an X-ray

Answer 33

Elastic cartilage

Question 34

The annulus fibrosis is made up of

Answer 34

Fibrocartilage

Question 35

Fibrocartilage is made up of which type of collagen?

Answer 35

Type I

Question 36

Bone can form in two ways. Is the final product different depending on the mechanism?

Answer 36

No

Question 37

Bone formation used for bones with a complex shape where a cartilage model is laid down first and then replced by bone

Answer 37

Endochondral bone formation

Question 38

What are the two ways the bone can form?

Answer 38

1. ) Endochondral (complex shape) | 2. ) Intramembranous (flat bones)

Question 39

Some of the flat bones of the face and skull develop via the

Answer 39

Intramembranous route

Question 40

Generates osteoblasts

Answer 40

Periosteum

Question 41

Prominent in developing bone

Answer 41

Osteoblasts

Question 42

Osteoblasts trapped in the matrix become

Answer 42

Osteocytes

Question 43

The matrix of bone is primarily

Answer 43

Type I collagen

Question 44

The unmineralized bone matrix is called the

Answer 44

Osteoid

Question 45

Mineralization (CaPO4) of the osteoid yields

Answer 45

Bone

Question 46

Membranous bone enlarges only through

Answer 46

Appositional growth

Question 47

The calcified matrix of bone is less than 10% H2O so the diffusion of nutrients and waste removal is

Answer 47

Poor

Question 48

To fix this, each osteocyte sits in an unmineralized

Answer 48

Lacunae

Question 49

The lacunae are connected to neighbors and blood supply by processes and

Answer 49

Gap junctions

Question 50

Processes, nutrients, and wastes pass through tunnels in the bone matrix called

Answer 50

Canaliculi

Question 51

Has appositional and interstitial growth

Answer 51

Cartilage

Question 52

Has appositional growth only

Answer 52

Bone

Question 53

Employs a transient cartilage scaffold that is ultimately replaced by bone

Answer 53

Endochondral Bone

Question 54

Takes advantage of cartilage's interstitial growth to creae complex shapes and lengthen bone

Answer 54

Endochondral bone formation

Question 55

Exist as a bone/cartilage hybrid from prenatal development to early adulthood

Answer 55

Most long bones

Question 56

Endochondral chondrocyte life cycles overlap, with those furthest from the resting zone being the most

Answer 56

Advanced

Question 57

Endochondral zones are maintained at the

Answer 57

Growth plate

Question 58

In endochronal bone formation, the initial bone product is -highly cellular and disorganized

Answer 58

Poor quality (woven bone)

Question 59

Soon after the initial bone is formed, osteoblasts and osteoclasts remodel the bone, forming

Answer 59

Lamellar bone

Question 60

Has fewer osteocytes and is highly organized

Answer 60

Lamellar bone

Question 61

A multinucleate bone destroyer that plays an essential role in bone maturation, remodeling, repair, and Ca2+ balance

Answer 61

Osteoclasts

Question 62

What do osteoclasts make to 1. ) Dissolve minerals 2. ) Degrade collagen

Answer 62

1. ) HCL | 2. ) Cathepsin K

Question 63

The divot osteoclasts make when breaking down bone is called

Answer 63

Howships Lacunae

Question 64

Covers the hollowships lacunae -new osteoblasts are generated and new bone is produced

Answer 64

Endosteum (analogous to periosteum)

Question 65

Spongy bone is in contact with blood supply and the trabeculae are lined with

Answer 65

Endosteum

Question 66

Compact bone has a system of channels called

Answer 66

Volkmann Canals and Haversian canals

Question 67

To remodel, osteoclasts invade compact bone and create a perpendicular tunnel called a

Answer 67

Volkmann canal

Question 68

Then, what enters into the volkmann canal?

Answer 68

Endosteum and blood vessels

Question 69

Osteoclasts then change direction and continue through the long axis of bone creating

Answer 69

Haversian Canal

Question 70

The Haversian canal is then lined with endosteum that initiates the

Answer 70

Rebuild and repair process

Question 71

Generates osteoblasts on outer aspect (bone side)

Answer 71

Endosteum

Question 72

Produce concentric layers of new bone and push the endosteum toward the center of the canal

Answer 72

Osteoblasts and osteocytes

Question 73

This process continues until the Haversian canal is nearly obliterated by

Answer 73

New bone formation

Question 74

Occupy the center of the remaining canal

Answer 74

Vessels and nerves

Question 75

New bone is populated by osteocytes in their lacunae, connected via processes through canaliculi in the matrix. The whole structure is called the

Answer 75

Osteon

Question 76

In the process of creating a new osteon, and old one is

Answer 76

Destroyed

Question 77

Remnants of an old osteon lost to the remodeling process

Answer 77

Interstitial lamellae

Question 78

Defines the outer edge of each osteon

Answer 78

Cement line

Question 79

The advantage in bone thickness you get from exercising will disappear after

Answer 79

20 years of inactivity

Question 80

Imbalance between bone reabsorption and bone production -affects primary trabecular bone

Answer 80

Osteoporosis

Question 81

Osteoporosis is probably due to diminished osteoblast activity, but most treatments target

Answer 81

Osteoclasts

Question 82

A discontinuous epithelial intima with no tight junctions or basal membrane -Very leaky

Answer 82

Synnovial inner layer

Question 83

What are the two layers of a joint capsule?

Answer 83

1. ) Delicate synovial inner layer | 2. ) Tough fibrous outer layer