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
