Cellular Structure Of Bone Flashcards Preview

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Flashcards in Cellular Structure Of Bone Deck (60)
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1

What are the 5 functions of bone?

→ Support and movement
→ Protection for internal organs
→ Bone marrow store
→ Mineral reservoir
→ Endocrine

2

Where is cortical compact bone found?

→ On the outside

3

How is cortical bone organised?

→ In sheet like structures
→ Surrounding a hollow structure called the Haversian canal

4

What are the repeating units of cortical bone?

→ Osteons

5

What are lacunae?

→ cell sized holes within the bone matrix

6

What are the function of Haversian canals?

→ Allow for blood vessel penetration

7

Where is trabecular bone found?

→ Near the head of the bone

8

What is the structure of trabecular bone?

→ spongy
→ interlocking struts with spaces inbetween

9

What is the function of trabecular bone?

→ Makes bone lighter

10

What is the composition of bone in %s?

→ Protein : organic osteoid matrix 25%
→ Mineral : 75%
→ Cells

11

What is the function of the organic protein matrix?

→ Gives flexibility and tensile strength

12

What is bone mineral?

→ Hydroxyapatite
→ Calcium and Phosphate

13

What is the function of bone mineral?

→ Gives bone rigidity and compressive strength

14

What are the 4 types of bone cells?

→ Osteoblasts
→ Osteoclasts
→ Osteocytes
→ Bone marrow cells

15

What are the two subtypes of bone marrow cells?

→ Mesenchymal cells
→ Haematopoietic cells

16

What do mesenchymal stem cells make?

→ Osteoblasts and osteocytes

17

Where are osteoblasts found?

→ Lining the inner surface of bone

18

Where are osteocytes found?

→ Encased within the bone matrix

19

What do haematopoietic stem cells give rise to?

→ Lymphoid lineage - lymphocytes
→ Myeloid lineage - RBC and macrophages

20

What are the 3 functions of osteoblasts?

→ Bone forming cells
→ Secrete osteoid collagen matrix of bone
→ Promote mineralisation of the osteoid

21

What are the 2 functions of osteoclasts?

→ Bone reabsorbing - digest old bone
→ Dissolve bone mineral and have enzymes to digest the organic matrix

22

What is the life cycle of osteoclasts controlled by?

→ Apoptosis

23

What is a protease that osteoclasts secrete?

→ Cathepsin K

24

What do osteoclasts secrete?

→ Acid and proteases that are active in acidic environments

25

What do osteoclasts look like?

→ They are large and multinucleate

26

What are osteocytes?

→ Terminally differentiated osteoblasts

27

What do osteocytes do?

→ They lay down bone matrix (organic material that becomes mineralised)

28

How do osteocytes extend?

→ Via multiple dendrites via minute canals in the bone matrix

29

What is the function of the lacunocanalicular system?

→ Maintains communication between the bone surface and blood vessels

30

How is bone continually renewed?

→ Old bone is continually resorbed and new bone is laid down
→ Cycle between osteoclasts digesting old bone and osteoblasts laying down new bone