Pathophysiology of Bone and Osteoarthritis

Question 1

what is the skeleton made up of from conception?

Answer 1

cartilage and fibrous membrane

Question 2

what is the process of bone growth called?

Answer 2

ossification

Question 3

what is the skeletal cartilage surrounded by?

Answer 3

dense perichondrium (dense irregular connective tissue that surrounds the cartilage of developing bone)

Question 4

what are the three types of cartilage found in the human body?

Answer 4

1. hyaline (joints)
2. elastic (external ear)
3. fibrocartilage (invertebrate discs)

Question 5

two ways cartilage grows?

Answer 5

1. appositional

2. interstitial

Question 6

explain how appositional growth occurs?

Answer 6

Mitotic division of preexisting chondrocytes in perichondrium secrete new matrix next to existing cartilage tissue (growth from the outside)

Question 7

explain how interstitial growth occurs?

Answer 7

Chondrocytes within cartilage divide and secrete new matrix, expanding the cartilage (growth from within)

Question 8

what are the functions of bones?

Answer 8

1. structural - support, protect, movement
2. mineral storage - calcium and phosphate
3. lipid storage
4. blood cell formation - hematopoiesis in marrow cavities

Question 9

what are the classifications of bones?

Answer 9

1. long bone e.g. humerus
2. short bone e.g. carpal, tarsal
3. flat bone e.g. ribs, skull
4. irregular bone e.g. hip, vertebrate

Question 10

what are the 2 major types of bones?

Answer 10

1. compact bone

2. cancellous bone (spongy)

Question 11

what is the role of compact bone?

Answer 11

for movement (mechanical) and protection
-made up of dense bone tissue on outside enclosed by periosteum (a thick fibrous membrane)

Question 12

what is the role of cancellous bone?

Answer 12

-regulates metabolic

Ca2+ and its storage. And stem cells are stored there too

Question 13

what is the head of the long bone called?

Answer 13

epiphysis

Question 14

what is the length of the long bone/bone shaft called?

Answer 14

diaphysis

Question 15

what is the periosteum?

Answer 15

Thick fibrous membrane and attachment for muscles and tendons Blood vessels, nerves, and lymphatic vessels

Question 16

what is the endosteum?

Answer 16

Thin membrane of connective tissue lining inner surface of (all) bony tissue

Question 17

what is the medullary cavity filled with?

Answer 17

yellow bone marrow called adipose

Question 18

where is red marrow contained in the bone?

Answer 18

in the epiphyses

Question 19

what is the metaphysis?

Answer 19

-Narrow area containing epiphyseal (growth) plate.

Question 20

what replaces the metaphysis and epiphyseal plate in fully formed adult bone?

Answer 20

osseous tissue for metaphysis and epiphyseal line

Question 21

what is the structural unit of the compact bone called?

Answer 21

osteon

Question 22

what is the concentric rings of calcified matrix in the compact bone called?

Answer 22

lamella

Question 23

what is the centre of each osteon called?

Answer 23

central canal where the blood vessels, lymphatic vessels and nerves run through to the periosteum and endosteum

Question 24

what are the three types of lamellae?

Answer 24

1. concentric
2. circumferential
3. interstitial

Question 25

what is the matrix structure of the spongy bone called?

Answer 25

trabeculae

Question 26

where does the spongy bone get its blood supply from?

Answer 26

1. blood vessels of periosteum

2. blood that circulates in the marrow cavities

Question 27

what is the structure of the trabeculae?

Answer 27

• contains irregularly arranged lamellae and osteocytes interconnected by cannaliculi
• trabeculae form along lines of stress to provide strength

Question 28

what is the space between trabeculae filled with?

Answer 28

bone marrow which is highly vascular

Question 29

what does the red bone marrow do?

Answer 29

• Supplies nutrients to osteocytes in trabeculae

* Forms red and white blood cells

Question 30

what does the yellow bone marrow do?

Answer 30

stores fat

Question 31

what bones are formed from intramembraneous ossification?

Answer 31

bones of skull and the clavicles (flat bones)

Question 32

what do osteoclasts and osteoblasts do?

Answer 32

Bone resorbing (osteoclasts) and bone forming cells (osteocytes and -blasts)

Question 33

what are resorption bays?

Answer 33

grooves formed by osteoclasts when breaking matrix

Question 34

how does bone resorption work?

Answer 34

• osteoclast secrete lysosomal enzymes that digest organic matrix
• also secrete acids that convert calcium salts into soluble forms

Question 35

what happens to the matrix once digested by the lysosomal enzymes?

Answer 35

transcytosed across the osteoclast cell where it is secreted into the interstitial fluid and then into the blood

Question 36

what is osteoarthritis?

Answer 36

degenerative disease of synovial joints, characterised by breakdown of articular cartilage and proliferative changes of surrounding bones

Question 37

where is the most common site of osteoarthritis?

Answer 37

the knee joint

Question 38

is osteoarthritis inflammatory or not?

Answer 38

mainly a non-inflammtory diseases of the synovial joints

Question 39

what are risk factors of osteoarthritis?

Answer 39

1. obesity
2. occupation
3. joint injury
4. joint alignment
5. bone shape
6. age
7. genetics
8. nutrition

Question 40

non-pharmacological treatment of osteoarthritis?

Answer 40

1. provide appropriate info and education
2. increased activity and exercise
3. weight loss if needs be

Question 41

what is first line treatment to osteoarthritis?

Answer 41

1. paracetamol

2. topical NSAID

Question 42

what to substitute paracetamol with or add to it if ineffective or insufficient?

Answer 42

Oral NSAID or Cox 2 inhibitor with a PPI