Histology of Bone an Joint

Question 1

Hyaline cartilage is made out of

Answer 1

Collagen type 2
Aggrecans (chondroitin sulphate, heparan suphate)
Hyaluronic Acid
Chondronectin

Question 2

what is connective tissue made of?

Answer 2

Cells + Ground Substance + Fibres

Question 3

where can you find collagen type 2?

Answer 3

Hyaline Cartilage

Question 4

if to hyaline cartilage elastin is added we obtain?

Answer 4

elastic cartilage

Question 5

elastic cartilage is found in?

Answer 5

ears, epiglottis and larynx

Question 6

Fibrocartilage can be described as

Answer 6

mixture of dense connective tissue and isolated islands of cartilage

Question 7

Fibroblasts differentiate into

Answer 7

Chondrocytes

Question 8

in fibrocartilage the main type of collagen found is

Answer 8

Type 1 collagen

Question 9

Fibrous Cartilage gas perichondrium T/F

Answer 9

F

Question 10

where can fibrocartilage be found?

Answer 10

meniscus and intervertebral discs

Question 11

what is the structure of a intervertebral disc?

Answer 11

external ring of fibrocartilage (annulus fibrosis)
nucleus pulposus (collagen type 2)

Question 12

around what age does the nucleus pulpous disappears

Answer 12

~20 yo

Question 13

what are the 2 pain types of bone

Answer 13

Compact Bone

Trabecular Bone

Question 14

where are the Haversian Systems found?

Answer 14

in compact bone

Question 15

what is a Haversian System?

Answer 15

Columns of bone made of lamellae (layers) around a blood vessel that run longitudinal to the bone and parallel to the lines of stress

Question 16

What are the main 3 types of cells found in bone?

Answer 16

osteoblast
osteocyte
osteoclast

Question 17

filling the trabecular bone one can find either

Answer 17

Yellow or Red bone marrow

Question 18

Can yellow marrow become haematopoietic again?

Answer 18

yes, it preserves some cells with haematopoietic potential

Question 19

Red Marrow’s capillaries have —-1—- instead of capillaries

Answer 19

Sinusoids, to allow material leakage

Question 20

Some of the bones that are important for haematopoiesis in the adult are

Answer 20

jaw
scapula
skull
pelvis

Question 21

what is the periosteum?

Answer 21

layer of connective tissue that covers bone outside

inside is the endosteum

Question 22

what can be found in the outer layer of the periosteum?

Answer 22

more fibrous layer, fibroblasts blood vessels and collagen

Question 23

what can be found in the inner layer of the periosteum? and what is it similar to?

Answer 23

more cellular than the outer, osteoprogenitor cells can be found there
Endosteum

Question 24

where in the bone there is no periosteum?

Answer 24

where there is the insertion of tendons and ligaments

Question 25

at the site of tendon insertion to the bone the collagen fibres are continuous with those collagen fibres within the bone T/F? this is called....

Answer 25

T | Sharpey's Fibres

Question 26

blood supply to the bone occurs at 2 discrete sites these are

Answer 26

Epiphysis (small retinacular arteries) | Diaphysis (large artery that subdivides in the marrow)

Question 27

hyaline cartilage of the articulatory surface has a perichondrium and is heavy vascularised T/F

Answer 27

F No perichondrium, not heavily vascularised if the cartilage is damaged it will take a long time to repair

Question 28

Synovial Fluid is similar to what other substance in the body

Answer 28

Plasma as it also is an ultrafiltrate of plasma with the addition of proteoglycans to make it more slippery

Question 29

the synovial membrane is an epithelium T/F

Answer 29

F just a stack of cells heavily leaky not many adhesion between the molecules (no intercalated discs)

Question 30

what are the cells that make up the synovial membrane?

Answer 30

Type A Synoviocytes (Macrophages) | Type B Synoviocytes (Fibroblasts)

Question 31

in the synovial membrane which layer is the main producer of fluid

Answer 31

the Subintimal layer (fibrous connective tissue, heavy vascularisation)

Question 32

Different name for a OSTEON

Answer 32

Haversian System

Question 33

what is the metabolic unit of the bone?

Answer 33

Haversian System

Question 34

osteoprogenitor cells of bone can be found in

Answer 34

Inner layer of the periosteum and endosteum

Question 35

Where are localised osteoblasts and what is their function?

Answer 35

on the surface of the bone | lay down matrix that will become bone (OSTEOID)

Question 36

main type of collagen found in bone?

Answer 36

Type 1 Collagen

Question 37

Where are osteocytes found? function?

Answer 37

within the lamellae of bone in the Haversian System --> Maintain bone healthy (has little processes that connect one with another and ultimately with a blood vessel). Can reabsorb bone to release Ca+2 if needed

Question 38

osteoclast characteristics? function

Answer 38

Giant, multinucleate cells that DESTROY bone creates a little pit underneath it, and seals itself around it, releasing acid products and enzymes (proteases and phosphatases) for the breakdown of bone

Question 39

what can be measured in plasma in order to ascertain osteoclast activity?

Answer 39

Tartrate Resistant Acid Phosphatase

Question 40

what is the main driver for increased osteoclast activity?

Answer 40

PTH

Question 41

cell lineage osteoclasts come from?

Answer 41

monocyte/macrophage lineage from the bone marrow

Question 42

During foetal development what are the 2 main types of bone laid down?

Answer 42

Membrane Bone | Endochondral Bone

Question 43

What is the process of membrane bone formation? what are some examples?

Answer 43

bone directly deposited into embryonic tissue from the mesenchyme skull, mandible, flat bones of face and clavicles

Question 44

All weight baring bone and extremity bones are of which formation type?

Answer 44

Endochondral bone

Question 45

Endochondral Bone formation requires transforming cartilage into bone T/F

Answer 45

F | Not making bone out of cartilage but rather destroying cartilage whilst making bone using the cartilage as a mould

Question 46

Describe the formation of bone from the cartilage mould

Answer 46

Bone collar forms around diaphysis ■ The cartilage beneath the ollar degenerates ■ Blood vessels invade, bring in bone cell progenitors ■ A second nucleus of ossification appears in each epiphysis ■ Zones of ossification grow together, but leave a thin zone of cartilage, the growth plate 

Question 47

when'd does the growth plate disappears?

Answer 47

~ 21-22 y

Question 48

what are the layers of the growth plate?

Answer 48

``` Resting Zone Proliferation Zone Maturation Zone Hypertrophic Zone Ossification ```

Question 49

during development or after injury (during repair) a specific kind of bone is produced what is its name? what are its characteristics?

Answer 49

Woven Bone | more cellular, more collagen No Haversian Systems (little ossification, not very strong)

Question 50

Remodelling of bone occurs down the lines of ---1--- of the bone

Answer 50

Lines of Stress

Question 51

order of events for bone remodelling

Answer 51

Osteoclast Reabsorption Invasion of the blood vessel Osteoblast deposition of bone in lamella (osteoblast trapped become osteocytes)