Injury and healing Flashcards

1
Q

Some functions of the skeleton

A

Protects organs, store of calcium and phosphate and produces blood cells.

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2
Q

What are mesenchymal stem cells?

A

Stem cells that can give rise to different connective tissue cells.

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3
Q

What are the two types of bone formation?

A

Intramembranous and endochondral.

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4
Q

What kind of ossification forms flat bones?

A

Intramembranous ossification.

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5
Q

What kind of ossification forms long bones?

A

Endochondral ossification.

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6
Q

Key difference between intramembranous and endochondral ossification?

A

Intramembranous produced bone from fibrous membrane (straight from mesenchymal cells) while endochondral produces bone from hyaline cartilage model.

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7
Q

How does intramembrous ossification occur?

A

MSC’s form osteoblasts. Osteoblasts cluster together and secrete osteoid which traps osteoblasts to form osteocytes. MSC’s form periosteum and formation of trabecular matrix occurs. Crowded red blood cells condense into red bone marrow.

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8
Q

How is bone marrow anatomically positioned differently in flat bones and long bones?

A

Bone marrow is present in a cavity in a long bone but in a flat bone it isn’t.

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9
Q

What are osteons and where are they located?

A

Osteons are the units that make up cortical bone.

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10
Q

What are the structures and cells present in an osteon?

A

Haversian canal, bone matrix and osteocytes, osteoblasts, volkmann’s canal.

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11
Q

What is the haversian canal?

A

Structure present in the centre of an osteon; contains blood vessels, nerves and lymph vessels.

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12
Q

What are the concentric lamellae in an osteon?

A

Rings of bone matrix.

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13
Q

What are the lacunae in an osteon?

A

Between rings, contain osteocytes.

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14
Q

What are the interstitial lamella?

A

Spaces inbetween osteons.

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15
Q

Where would you find osteoblasts in an osteon?

A

Outer part of the osteon.

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16
Q

What is a volkmann’s canal and where would you find it?

A

Transverse canals that are inbetween haversian canals or emerge from periosteum that contain blood vessels.

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17
Q

What is trabeculae?

A

Makes up cancellous bone (spongy bone) and has honeycomb structure.

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18
Q

Osteoblasts function

A

Forms bone by secreting osteoid and catalysing mineralisation of osteoid.

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19
Q

What is osteoid?

A

Organic bone matrix (unmineralised).

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20
Q

What proteins are present in osteoid?

A

Collagen type I, proteoglycans and glycoproteins

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21
Q

What makes up the ground substance in osteoid?

A

Proteoglycans and glycoproteins.

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22
Q

Osteocyte function

A

Senses mechanical strain to direct osteoblasts and osteoclast activity.

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23
Q

What connects osteocytes and what’s the function of these connections?

A

Canaliculi. Exchange of nutrients.

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24
Q

Osteoclast function

A

Degrade bone by phagocytosis.

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25
Q

What are osteoclasts derived from?

A

Bone marrow.

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26
Q

What converts osteoblast to osteocytes?

A

When osteoblasts get embedded in osteoid.

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27
Q

What is inorganic bone matrix made up of?

A

Calcium hydroxyapatite and osteocalcium phosphate.

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28
Q

What are osteogenic cells?

A

Bone stem cells derived from MSC’s.

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29
Q

Where would you find osteogenic cells?

A

Periosteum.

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30
Q

Where would you find osteoblasts?

A

Periosteum and endosteum.

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31
Q

What is the endosteum?

A

Membrane that lines medullary cavity.

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32
Q

Where would you find osteocytes?

A

Bone matrix.

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33
Q

Where would you find osteoclasts?

A

Sites of old and injured bone.

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34
Q

Can you describe the process of endochondral ossification?

A

Bone collar forms around diaphysis of the hyaline cartilage model. Cartilage calcifies in the center of the diaphysis and then develops cavities. Blood vessel of periosteal bud invades internal cavities and formation of cancellous bone occurs. Diaphysis elongates and medullary cavity forms. Secondary ossification center develops after birth at the epiphysis. Ossification occurs at epiphysis; cartilage is replaced by bone. Eventually only cartilage left is at epiphyseal plate and articular cartilage.

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35
Q

What is the diaphysis?

A

Central part of long bone.

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36
Q

What does invasion of periosteal bud mean?

A

A periosteal bud, which consists of blood vessels, lymph vessels and nerves, invades the cavity left by the chondrocytes.

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37
Q

What cell types does the periosteal bud contain?

A

The vascularization utlimately carries hemopoietic cells, osteoblasts and osteoclasts inside the cavity. The hemopoietic cells will later form the bone marrow.

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38
Q

How is the bone collar formed in endochondral ossification?

A

The osteoblasts secretes osteoid against the shaft of the cartilage model.

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39
Q

What is articular cartilage?

A

Cartilage present on the surface of the bone at the joint only.

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40
Q

What is the epiphysis?

A

Zone between epiphyseal plate and joint.

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41
Q

What cells break down cartilage?

A

Osteoclasts.

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42
Q

What is the periosteum?

A

Connective tissue covering of bone.

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43
Q

What is the outer cortex made up of?

A

Cortical bone.

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44
Q

Where is cancellous bone located in long bone?

A

Epiphysis.

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45
Q

What does medullary cavity in long bones contain in an adult?

A

Mostly yellow bone marrow.

46
Q

What is interstitial bone growth?

A

Increase in the length of the bone.

47
Q

What is appositional bone growth?

A

Increase in the thickness of the bone.

48
Q

Where does interstitial growth occur?

A

At epiphyseal plate.

49
Q

What is the epiphyseal side in interstitial growth?

A

Active hyaline cartilage dividing to form hyaline cartilage matrix.

50
Q

What is the diaphyseal side in interstitial growth?

A

Cartilage calcifies and dies; replaced by bone.

51
Q

When does appositional growth occur?

A

Throughout life in response to stress.

52
Q

Describe how appositional growth occurs

A

Bone formation at periosteum produces ridge parallel to blood vessel. This creates a groove for blood vessel. Periosteal ridges meet and fuse creating a tunnel for the blood vessel. Osteoblasts in endosteum build new concentric lamellae inward towards center of tunnel; forming a new osteon. Bone grows outwards as osteoblasts in periosteum build new circumferential lamella. Process repeats and results in increase in bone thickness.

53
Q

Difference between osteoporosis and osteomalacia

A

Osteoporosis is loss of bone but bone mineral : organic bone matrix is normal. Osteomalacia is demineralisation and so leads to low bone mineral : organic bone matrix.

54
Q

What is ostopenia?

A

Less severe osteoporosis.

55
Q

What results in osteoporosis? What does bone look like in a patient with osteoporosis?

A

Greater osteoclast activity than osteoblast activity. Disrupted microarchitecture of bone.

56
Q

Risks factors for osteoporosis?

A

Age, sex, alcohol intake, use of glucocorticoids, hypogonadism.

57
Q

What causes postmenopausal osteoporosis?

A

Reduction is oestrogen. Oestrogen is protective of bone.

58
Q

Osteoporosis symptoms

A

Low energy trauma resulting in a fracture. Bad posture.

59
Q

How does a vitamin D deficiency cause osteomalacia/rickets?

A

Less mineralisation of bone matrix due to low calcium and phosphate in the blood.

60
Q

What is congenital osteogenesis imperfecta?

A

Hereditary condition that can result in decreased secretion or abnormal collagen type 1.

61
Q

What in the bones is affected in a patient with congenital osteogenesis imperfecta?

A

Insufficient osteoid production as collagen type I makes up the organic matrix.

62
Q

What is pagents disease?

A

Excessive bone break down and disorganised remodelling.

63
Q

What can pagents disease develop into?

A

Malignant disease.

64
Q

What effect can prostate cancer metastases have on bone?

A

Blastic effect - Bone growth.

65
Q

What effect can breast cancer metastases have on bone?

A

Blastic and lytic effects.

66
Q

What effects can kidney,thyroid and lunger cancer metastases have on bone?

A

Lytic effect - forms holes in the bone.

67
Q

What is a haematoma?

A

Pool of clotted blood outside of blood vessel.

68
Q

When a large fracture where bone edges are not close and there is low stability what occurs at the fracture?

A

Haematoma formation, release of cytokines and angiogenesis at fracture. Soft callus formation which is converted to a hard callus. Excess bone is removed.

69
Q

What is a soft callus made of?

A

Cartilage - type II collagen.

70
Q

What is a hard callus made of?

A

Bone - type I collagen.

71
Q

Key difference between primary bone healing and secondary bone healing

A

In primary bone healing there is no formation of a callus and so no remodelling.

72
Q

When can primary bone healing occur?

A

Bone edges are very close and there is absolute stability (very little motion).

73
Q

Where may primary bone healing be important?

A

Joints as you don’t want remodelling.

74
Q

Another name for primary bone healing?

A

Intramembranous healing.

75
Q

Another name for secondary bone healing?

A

Endochondral healing

76
Q

What is a closed reduction?

A

Non invasive way of putting the broken bone back in place, which allows it to grow back together in better alignment.

77
Q

What fracture is closed reduction treatment common?

A

Distal radius fracture.

78
Q

Before a closed reduction is done what is adminsitered?

A

Haematoma block such as lidocaine.

79
Q

What is used after a closed reduction and why?

A

Cast or splint to prevent misalignment after procedure.

80
Q

What are the two different ways of holding a bone and what’s the difference?

A

Closed and fixation. Fixation requires surgical intervention.

81
Q

Two types of closed bone holding?

A

Plaster cast and traction

82
Q

What is traction?

A

Use of pulleys and weights to reposition fractured bone.

83
Q

What is a closed fracture and what can it result in?

A

The bone is broken, but the skin is intact. Can result in compartment syndrome.

84
Q

What is ligaments and tendons predominantly made of?

A

Type I collagen.

85
Q

What do ligaments connect?

A

Bone to bone.

86
Q

What do ligaments do and how do they do it?

A

Provide stability by restricting joint movement. Ligaments also provide proprioception.

87
Q

What is proprioception?

A

Body’s ability to perceive movement and location of a body part.

88
Q

How to multiple ligaments work together?

A

Restrict movement in different planes to provide stability.

89
Q

What do tendons connect?

A

Connect muscle to bone.

90
Q

What do tendons do?

A

Transmit force.

91
Q

What usually causes a ligament injury?

A

Too much of a pivoting force or too much rotation.

92
Q

What usually causes a tendon injury?

A

Eccentric contraction.

93
Q

What is an avulsion injury?

A

Chunk of bone attached to tendon or ligament gets pulled away from main part of bone.

94
Q

4 stages of healing of a tendon or ligament?

A

Bleeding, inflammation, proliferation and remodelling.

95
Q

Healing of tendon or ligament compared to bone?

A

Takes longer to heal and doesn’t heal as well as bone.

96
Q

How does the ACL provide stability?

A

Prevents tibia from going too far forward and also limits rotational movement.

97
Q

How do you test for an ACL injury?

A

Check to see if tibia moves too far forward.

98
Q

What are meniscus?

A

Cartilage that acts as a shock absorber.

99
Q

Why is playing sports with an ACL injury bad?

A

You can damage cartilage in knee.

100
Q

What can you sometimes do to compensate for an ACL injury?

A

Strengthen muscles.

101
Q

When doing an ACL reconstruction is the ACL usually repaired or replaced?

A

Replaced.

102
Q

What are the 3 ways in which an ACL can be reconstructed?

A

Use of an autograft, use of an allograft or use of a synthetic ACL.

103
Q

What is a locked knee?

A

Can’t fully extend knee.

104
Q

What usually causes a locked knee and how?

A

Due to meniscus tear. Fragment of meniscus can become stuck in knee joint.

105
Q

What increases your risk of a tendon achilles rupture?

A

Anabolic steroid use and fluoroquinolone use.

106
Q

How do you check if someone has ruptured their achilles?

A

Difficulty walking. Unable to perform heel raises. Gap in tendon when you feel tendon.

107
Q

Why doesn’t a tendon surgical repair restore tendon to 100% function?

A

Bad tendon tissue has to be removed. Loss of tendon tissue. If it heals well there is still scarring.

108
Q

Complications of doing a ligament or tendon operation?

A

DVT, infection and tendon re-rupture.

109
Q

What can stress to the bone result in?

A

Stress fracture.

110
Q

Osteoporosis treatments?

A

Bisphosphonates. SERMS (selective oestrogen receptor modulators - simillar to oestrogen). Hormone replacement therapy.

111
Q

Treatment for transient synovitis?

A

NSAID’s