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Flashcards in Bone And Cartilage 2 Deck (19)
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1
Q

What are the visible lines surrounding osteon

A

Cement lines

2
Q

On outside of the bone is a connective tissue periosteum

Outer layers of bone are organised in LAMELLAE that run around the bone

A

What are the outer circumferential LAMELLAE

3
Q

What are osteoprigenitor cells

A

Located on bone surfaces like periosteum these cells serve as a pool of reserve osteoblasts

4
Q

What are osteaoblasts

A

Bone forming cells found on the surface of developing bone

Have plentiful RER and prominent mito

5
Q

What are osteocytes

A

Bone cell trapped in bone matrix

6
Q

What are osteoclasts

A

Large multi nucleated cells found on surface of bone and responsible for resorption

7
Q

What is osteoid

A

The osteoblasts secretion which consists of collagen, gags, proteoglycans, and other organic compounds

8
Q

LAMELLAE vs woven bone

A

During normal development bone laid in lamellar collagen fibres
Haphazard form of being laid down is woven bone which is as strong as lamellar and then remodelled to lamellar

9
Q

What are osteoclasts derived from

A

Macrophage
A lot of them fuse and form a giant cell
In how ship lacuna

10
Q

What are osteons

A

Remodelling causes new osteons to be laid down over old ones

11
Q

What is interstitial lamellae

A

LAMELLAE between osteons are the remnants of old osteons

12
Q

What is intramembranous ossification

A

Mesenchymal cells diff into osteoblasts and begin syn and secret osteoid at multiple sites
As cells become trapped become osteocytes
At centres of ossifications grow outwards
(Eminences)

13
Q

What are some examples of bones which safe produced by intramembranous ossification

A

Flat bones of cranial vault
Mandible
Middle portion of clavicle

14
Q

What is endochondral ossification

A

Push bone out from middle

15
Q

What are some examples of bones produced by endochondral ossification

A

Most long bones
Base of skull
Medial and lateral ends of the clavicle

16
Q

What is osteoporosis

A

Balance between bone destruction and formation becomes uneven
Calcium inhib bone destruction
Parathyroid hormone promotes bone destruction
When oestrogen falls bone destruction increases

17
Q

What is Paget’s disease

A

Results in erosion of bone probably because of uncontrolled osteoclast activity

18
Q

What is osteomalacia

A

Failure of osteoid to properly mineralise

Insufficient dietary intake of calcium or renal dysfunction of phosphate loss

19
Q

How is trabecular and cortical bone different

A

The bone cells and matrix are similar in compact and trabecular bone
The main diff is presence of spaces adjacent to trabecular bone