UNIT 4.2 BONE TISSUE

Question 1

what is the build u of bone?

Answer 1

1. resident cell + bone matrix (fibres collagen 1 + groundsubstace)

Question 2

what is an Osteogenic cell?

Answer 2

(undifferentiated cell)

– can divide to replace themselves &osteoblasts

Question 3

where can you find an ostegogenic cell?

Answer 3

-inner layer of periosteum, in endosteum +in channels with blood vessels.

Question 4

what is the periosteum?

Answer 4

CT enveloping bones except surfaces of joints.

Question 5

what is endosteum?

Answer 5

lines inner surface of bony tissue that forms medullary cavity of long bones

Question 6

what do osetoblasts do?

Answer 6

form the matrix which is initial non calcified GS

Question 7

JOB OF Osteocytes?

Answer 7

mature cells =no longer secrete matrix.

- maintain bone tissue metabolism.

Question 8

where are osteocytes located?

Answer 8

lacunae

Question 9

what are osteoclasts?

Answer 9

multinucleated cells from fused monocytes(macrophages)

Question 10

job of osteoclast?

Answer 10

secrete lysosomal enzymes +acids to digest+reabsorb bone matrix.

Question 11

what is the bone matrix made of?

Answer 11

1. inorganic salts: hardness
   - hydroxyapitate
   - calciumcarbonate
   - minerals
2. collagen fibres =tensile strength +flex

Question 12

what do osteoblasts need to start calcification of bone matrix?

Answer 12

only occurs in the presence of collagen fibres

Question 13

what are 2 types of bone tissue?

Answer 13

1. compact =osteons

2. spongy = trabeculae

Question 14

in compact bone tissue, what do the osteons have? 2

Answer 14

1-bvs, lymthpatic, nerve+osteocytes

2-along lines of stress

Question 15

which BT can you see with naked eye?

Answer 15

spongy

Question 16

what does spongy tissue contain? 3

Answer 16

• trabeculae
• red bone marrow
• cavities

Question 17

what does the spongy bone make up? 4

Answer 17

1. structure of short,
2. flat
3. irregular bones
4. epiphyses (end part) of long bones.

Question 18

function of bone tissue= 4

Answer 18

1. tendons attach muscle to bone

2.Mineral homeostasis:
(calcium & phosphate).

3) Hematopoiesis: in red bone marrow of spongy tissue
4) Energy storage: yellow bone marrow (adipocytes)

Question 19

types of bones and example=5

Answer 19

1. longbones=femur,phalages
2. flat=skull+scapula
3. short=taral+carpal
4. sesamoid=patella
5. irregular=ribs, clavicle, vert

Question 20

what type of BT is found in short and irregular bones?

Answer 20

inside= spongy
outside= compact

Question 21

what type of BT is found in flat bones?

Answer 21

2x compact tissue separated by spongy

Question 22

what type of BT is found in long bones? (2)

Answer 22

1) epiphyseal= spongy bone + superficial compact

2) diaphysis=compact + medullary cavity

Question 23

what are parts of long bone?

Answer 23

1. diaphysis
2. medullary cavity
3. epiphysis
4. metaphysis
5. articular cartilage

Question 24

what is the diaphysis of the long bone?

Answer 24

shaft of bone (medullary cavity)

Question 25

what is medullary cavity of long bone?

Answer 25

yellow bone marrow / red +adipose tissue

Question 26

what is the epiphysis of long bone?

Answer 26

one end of a long bone

Question 27

what is the Metaphysis of the long bone?

Answer 27

area between epiphysis+diaphysis and includes epiphyseal plate in growing bones.

Question 28

what does the endosteum of the long bone (diaphysis) do?

Answer 28

1. lines medullary cavity (has red/yellow bone marrow) = hematopietic 2. -volkamans +haverns canal 3 -osteogenic (osteogenic cells)

Question 29

what does the periosteum do? | and what are the 2 types?

Answer 29

- lines bone 1. fibrous = external =DICT 2. osteogenic internal =bvs+OC

Question 30

function of the periosteum? 3

Answer 30

1 -bone growth+ fracture repair 2. -Anchors periosteum to bone via perforating bundles of collagen fibres/ Sharpey’s fibres) 3-bone irrigation via volkmans canal

Question 31

characteristics of compact bone= 2

Answer 31

1. resists stress by weight | 2. osteon surrounded by calcified matrix+ haverns canal

Question 32

how do finger like projections of octyocytes in lacunae communicate?

Answer 32

via canaliculi

Question 33

how do volkans canal provide irrigation and vascularisation ?

Answer 33

penetrates compact bone thru PERIOSTEUM via periosteal arties/viens

Question 34

what does interstitial lamellae represent?

Answer 34

older osteons that have been partially removed during tissue remodelling.

Question 35

what is circumferential lamellae?

Answer 35

- develop during initial bone formation. - outer + inner - outer= connect to periosteum via sharpey's firbres

Question 36

how is nutrients passed onto diaphysis, spongy and RBM?

Answer 36

nutrient arties/viens via n utrient foramen

Question 37

how is blood passed to RBM and metaphysis+epiphysis of bone?

Answer 37

via metaphyseal + epiphyseal arties/veins

Question 38

what are stages of bone formation? 4

Answer 38

* 1st Differentiation of osteoprotenitor- Osteoblast cells * 2nd Formation of matrix (osteoblasts) * 3rd Mineralization of matrix (hydroxyapatite) * 4th Appearance of lacunae (osteocytes)

Question 39

what is Intramembranous ossification?

Answer 39

formation of bone directly from mesenchyme

Question 40

what is Endochondral ossification?

Answer 40

formation of bone from hyaline cartilage models

Question 41

how does the growth in the length of bone happen?

Answer 41

1. Growth of cartilage in the epiphyseal side of the epiphyseal plate. 2. Replacement of cartilage with bone in the diaphyseal side of the epiphyseal plate.

Question 42

what are the different zones for growth of the epiphyseal plate? 4

Answer 42

1•Zone of resting cartilage –anchors growth plate to bone 2•Zone of proliferating cartilage 3•Zone of hypertrophic cartilage 4•Zone of calcified cartilage -most cells die osteoblasts & capillaries move in to create bone over calcified cartilage

Question 43

vitamin C for?

Answer 43

for collagen formation

Question 44

vitamin D for?

Answer 44

for calcium absorption

Question 45

During childhood: insulin-like growth factor, hGH does what?

Answer 45

(growth), promotes cell division at epiphyseal plate

Question 46

APPOSITIONAL GROWTH=WIDTH - steps:

Answer 46

1. Periosteal cells>osteoblasts =matrix. 2. Osteoblasts >osteocytes. Formation of ridges. 3. Ridges fuse and periosteum becomes the endosteum. 4. osteoblasts= make New concentric lamellae in endosteum 5. Osteoblasts under periosteum form new circumferential lamellae, forming an osteon.