Bone Flashcards

1
Q

What are some of the functions of bone?

A

Weight bearing/support

Protection

Mineral store

Blood formation

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2
Q

What is the gross anatomy of a bone composed of?

A

Compact bone

Spongy bone

Blood vessels

Medullary cavity

Bone marrow

Membranes (periosteum/endosteum)

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3
Q

What are the circular structures that compact bone is organised into?

A

Osteons/Haversian systems

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4
Q

What are the osteons/Haversian canals composed of?

A

Central Haversian canal and horizontal perforating/Volkmann’s canals where blood vessels are

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5
Q

What is found in Volkmann’s canals?

A

Blood vessels

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6
Q

What is found in the Haversian canal?

A

Osteocytes and concentric rings of bone marrow

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7
Q

What is an osterocyte?

A

A bone cell

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8
Q

What is more dense out of spongy and compact bone?

A

Spongy bone

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9
Q

What network is found in spongy bone?

A

Network of lamellated trabeculae filled with bone marrow

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10
Q

What is the lamellated trabeculae filled with?

A

Bone marrow

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11
Q

Are Haversian systems found in spongy bone?

A

No

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12
Q

What does the orientation of trabeculae reflect?

A

Direction of the mechnical force

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13
Q

What are some different types of bones?

A

Flat bone (frontal)

Sutural bone

Short bone (carpal)

Irregular bone (vertebra)

Sesamoid bone (patella)

Long bone (femur)

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14
Q

What are the 2 types of bone formation?

A

Endochrondral

Intramembraneous

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15
Q

What is the process of endochondrial ossification?

A
  1. Bone forms as cartilage model
  2. Blood vessels invase cartilage
  3. Cartilage replaced with bone
  4. Cartilage reamins in epiphyseal growth plate, which eventually ossifies
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16
Q

What is ossification?

A

Process of laying down new bone material by cells called osteoblasts

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17
Q

What is the process of intramembraneous ossification?

A
  1. Mesenchymal cells develop into osteoprogenitor cells that mature into osteoblasts that start developing bone
  2. Residual mesenchymal cells develop blood vessels and bone marrow
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18
Q

What are the 3 cells that make up bone?

A

Osteoblasts

Osteocyte

Osteoclasts

19
Q

What do osteoblasts do?

A

Form new bone

20
Q

What do osteoclasts do?

A

Destroys old bone

21
Q

What is the extracellular matrix composed of?

A

45% hydroxyapatite crystals (complex form of calcium phosphate)

35% collagen (type I)

20% water

22
Q

What do minerals do to bones?

A

Make them stiff and give them strength

23
Q

What does collagen do to bones?

A

Gives them flexibility, increasing strength under tension

24
Q

Why is bone dynamic?

A

Due to bone turnover, new bone is constantly being formed

25
Q

What is the process of new bone constantly being formed?

A
  1. Osteoclasts break down old bone
  2. Osteoblasts build new bone
26
Q

Are osteoblasts immature or mature?

A

Immature

27
Q

What are osteoblasts derived from?

A

Osteopreginitor cells

28
Q

What is a function of osteoblasts?

A

Produce the bone matrix

29
Q

What do osteoblasts do when they are surrounding by matrix?

A

Become osteocytes

30
Q

Are osteocytes mature or immature?

A

Mature

31
Q

Where are osteocytes found?

A

Inside lacunae

32
Q

What are osteocytes connected to each other by?

A

Canaliculi

33
Q

What does canalucili allow?

A

Osteocytes to communicate with each other

34
Q

What are functions of osteocytes?

A

Maintain the bone matrix

Sense mechanical force

35
Q

What are osteoclasts derived from?

A

Haematopoietic stem cells

36
Q

Where are osteoclasts found?

A

On bone surfaces

37
Q

What is the function of osteoclasts?

A

Resorb bone matrix

38
Q

What is the resorption pit of an osteroclast called?

A

Howship’s lacunae

39
Q

When does bone disease occur?

A

When remodelling is not balanced

40
Q

What are some examples of bone diseases?

A

Osteoporosis (resorption > formation)

Paget’s disease (resorption and formation greater)

Osteopetrosis (low resorption)

41
Q

What is bone mass controlled by?

A

Genes and the environment

42
Q

What happens to bone mass as you get older?

A

It decreases

43
Q

How does mechnical load regulate bone mass?

A

You loss what you don’t use