Bone

Question 1

What is Periosteum?

Answer 1

• tough Fibrous membrane round the outer surface of the bone not covered by the articular surface
• delivers blood and nutrients to the bone. Is able to form new bone - good for healing fractures
• has an outer fibrous layer (mostly collagen) and inner cellular layer (osteoblasts).

Question 2

What is compact bone (cortical bone)?

Answer 2

• forms hard outer shell around most bones and forms the cortex
• formed from osteons
• protection, support and acting as a calcium store when needed

Question 3

What is cancellous bone (trabecular bone)?

Answer 3

• porus, vascularised and contains red bone marrow, in the epiphyses (end) of long bones
• can be converted to compact bone by osteoblasts (this takes place during embryo formation)
• storage of bone marrow, light weight, adds stength and flexability, mineral store

Question 4

What is the medullary cavity?

Answer 4

• hollow region within diaphysis filled with yellow marrow
• endosperm = membranous lining where bone remodelling occurs
• red and white blood cells are formed here

Question 5

What is the function of the greater trochanter?

Answer 5

• provides attachment for gluteal muscles

- provides extensors of hip with long lever arm

Question 6

What is the function of the lesser trochanter?

Answer 6

• provides insertion for iliopsoas muscle

Question 7

What is the function of the trochanteric fossa?

Answer 7

• lies between trochanter and femoral neck

- site of insertion for small rotor muscles of the hip

Question 8

What is the function of the medial and lateral condyles?

Answer 8

• provides an attachment for collateral ligaments of the stifle
• provide patella stability and articulation of the tibia

Question 9

What is the function of the extensor fossa?

Answer 9

• gives origin to the long digital extensor and peroneus tertius

Question 10

What is the function of the patella?

Answer 10

• sesamoid bone developed within the insertion of the quadriceps femoris

Question 11

What is the function of the intercondyler fossa?

Answer 11

• separates the 2 condyles

- articulation of the tibia and seats stabilisation ligaments in the knee

Question 12

What is the function of the trochlea?

Answer 12

• articulates with the patella

Question 13

What are the 3 parts of bone tissue?

Answer 13

1. Matrix
2. Cells
3. Vascular spaces

Question 14

What is the organic part of the matrix (osteoid)?

Answer 14

• contains type 1 collagen for flexibility, water, glycoproteins, proteoglycans and bone sialiproteins
• synthesised by osteoblasts
• mineralisation front = point where osteoid becomes bone tissue

Question 15

What is the inorganic part of the matrix?

Answer 15

• minerals inc. calcium and phosphorus
• 60-70% of bones dry mass
• radio opaque

Question 16

What is an osteoblast?

Answer 16

• derived from mesenchymal stem cells
• synthesise and secrete osteoid
• active in mineralisation

Question 17

What is an osteocyte?

Answer 17

• within matrix
• interconnected by dendritic processes
• derived from osteoblasts
• reside in lacunae connected by canaliculi

Question 18

What is an osteoclast?

Answer 18

• bone resorption
• large multinucleate
• release protons = acidic = demineralisation
• secrete proteases to destroy organic matrix
• derived from bone marrow

Question 19

What type of ossification involves formation of a cartilaginous precursor?

Answer 19

• endochondral

Question 20

What type of ossification is involved in formation of bones of the skull?

Answer 20

• intramembranous

Question 21

What type of ossification results in formation of woven bone that is later replaced by lamellar bone?

Answer 21

• intramembranous

Question 22

What type of ossification involves differentiation of mesenchymal stem cells into osteoblasts?

Answer 22

• intramembranous

Question 23

What type of ossification is involved in growth in length of bones?

Answer 23

• endochondral

Question 24

What type of ossification is involved in width of long bones?

Answer 24

• intramembranous

Question 25

Where does endochondral ossification take place?

Answer 25

- physes/ growth plates = increase length of long bone - epiphyses = increase in size link with joint cartilage growth - cuboidal bones of carpus and tarsus - repair of fractures (same as bone growth = no scar)

Question 26

What is the diaphysis?

Answer 26

- Shaft of long bone

Question 27

What is the metaphysis?

Answer 27

- flared region adjacent to epiphysis

Question 28

What is the epiphysis?

Answer 28

- rounded end of bone

Question 29

What is the axial skeleton?

Answer 29

- the bones forming the axis/ centre of the animal

Question 30

What is the appendicular skeleton?

Answer 30

- regions that are attached e.g bones of forelimb

Question 31

What are visceral bones?

Answer 31

- develop in soft tissues away from rest of the skeleton e.g Os penis in dog and cat Os cordis in heart of ruminants

Question 32

What is chondral ossification?

Answer 32

- bones ossify from cartilage precursor | e. g most limb bones - humerus, radius etc

Question 33

What is membranous ossification?

Answer 33

- bones ossify directly from mesenchymal cells | e. g scapula and most bones of skull

Question 34

Chondral ossification bones

Answer 34

- found in load bearing areas | - often have specific fail/fracture configurations

Question 35

Membranous ossification bones

Answer 35

- found in non-load bearing areas | - fracture configuration = pebble on sheet of ice

Question 36

Long bones

Answer 36

- cylindrical shape - main part of bone is a column providing strength, expanded ends providing transfer of load - resist compression when loaded, act as levers and resist tension during muscle contraction - e.g humerus, femur, radius, tibia

Question 37

Short bones

Answer 37

- many sides, similar dimensions throughout (length, breadth, height) - found in groups of bones that act to transmit and disseminate forces through joints (distribute weight and force more evenly and reduce concussive forces) - one surface is always non-articular – for ligament attachment and vasculature - e.g carpal and tarsal bones

Question 38

Irregular bones

Answer 38

- have various jutting processes for muscle and ligament attachment - e.g vertebral bones

Question 39

Flat bones

Answer 39

- act as attachment for soft tissues and protect underlying tissues - e.g skull, scapula, pelvis and ribs

Question 40

Pneumatic bones

Answer 40

- bones that contain air spaces = light weight | - flat bones of skull

Question 41

Sesamoid bones

Answer 41

- provide additional strength and reduce wear over joints | - e.g redirect course of tendon (patella)

Question 42

What is the function of the greater and lesser tubercles?

Answer 42

- muscle attachment

Question 43

What is the function of the olecranon?

Answer 43

- allows movement and attachment of the ulnar

Question 44

What is the function of the head of the humerus?

Answer 44

- articular surface

Question 45

What is the function of the deltoid tuberosity?

Answer 45

- ridge (muscle attachment)