Session 7: Cartilage, Bone and Bone Fractures Flashcards
(94 cards)
1
Q
Cartilage is a connective tissue secreted by what cells?
A
Chondrocytes
2
Q
Chondrocytes are derived from the same precursor cells as what other cell type?
A
Fibroblasts
3
Q
Chondrocytes create fibrous material such as what two important proteins?
A
Collagen
Elastin
4
Q
Collagen and elastin provide cartilage with what two features?
A
Strength
Flexibility (Elasticity)
5
Q
Is cartilage innervated?
A
No
6
Q
Is cartilage vascular?
A
No, it is avascular
7
Q
If cartilage is not innervated and is avascular, how does it receive its nutrients and immune protection?
A
From surrounding fluid
8
Q
What are the three main types of cartilage found in the body?
A
Hyaline cartilage
Elastic cartilage
Fibrous cartilage
9
Q
Where is hyaline cartilage found?
A
Larynx, trachea, throat, nose
Joints where the surfaces are articulating each other
10
Q
Where would you find elastic cartilage in the body?
A
The outer ear
The epiglottis
The Eustachian tube
11
Q
Where would you find fibrous cartilage in the body?
A
Intervertebral discs
Pelvis symphysis
The menisci of the knee joint
12
Q
What is the function of hyaline cartilage?
A
Reduce friction
Absorb shock
13
Q
What is the function of elastic cartilage?
A
Provide shape and support
14
Q
What is the function of fibrous cartilage?
A
Provide rigidity
Absorb shock
15
Q
Bone is formed through which process?
A
Ossification
16
Q
Ossification can take on two forms depending on which type of bone is forming. What forms can bone take?
A
Flat bone
Long bone
Short bone
Irregular bone
17
Q
What are 4 examples of flat bone?
A
Skull, scapula, ribs, pelvis
18
Q
Where would you find long bones?
A
Arms
Legs
19
Q
Ossification that forms flat bones is known as what?
A
Intramembranous ossification
20
Q
What is the type of ossification that forms long, short and irregular bone?
A
Endochondrial ossification
21
Q
What cells differentiate in intramembranous ossification to give osteoblasts?
Where are these cells found?
A
Mesenchymal Stem Cells
In the embryonic fibrous connective tissue
22
Q
Osteoblasts lay down what?
A
Osteoid
23
Q
What happens to osteoblasts once they are surrounded by osteoid?
A
They become osteocytes
24
Q
What are formed when the osteoid calcifies?
A
It forms spicules which fuse to form trabeculae
25
What is the periosteum? How is it formed?
The fibrous sheet that covers the outer surface of bone and lays down connective tissue
Formed by condense mesenchyme
26
Intramembranous ossification also contributes to what important aspect of long bone formations?
What kind of growth is this?
Thickening
| Appositional growth
27
After the formation of what structure are endochondrial and intramembranous ossification much the same?
Spicule
28
Osteoblasts and osteoclasts are important for which process?
Osteoblasts are responsible for what?
Osteoclasts are responsible for what?
Bone remodelling
Depositing new bone
Reabsorbing/break down already formed bone
29
Osteoclasts release what two things to contribute to the break down of bone?
Hydrogen ions
| Lysosomal enzymes
30
What is the endosteum?
The fibrous sheet that lines the inner surface of all bones and lays down connective tissue
31
What kind of bone forms the external surfaces of bones?
Compact or cortical bone
32
What kind of bone forms a network of fine bony plates that combine strength with lightness?
Spongy or cancellous bone
33
Spaces within spongy bone are filled with what?
Bone marrow
34
What are the canals that run through the lamellae called?
| Are they orientated longitudinally or transversely?
Haversians canals orientate longitudinally
| Volkmann's canals orientate transversely
35
What do Haversians and Voklsmann's canals carry?
Blood vessels, lymph and nerves
36
How does immature bone differ from mature bone?
Immature bone has randomly arranged osteocytes
| Mature bone has osteocytes arranged within the concentric lamallae of osteons
37
Where do reabsorption canals run in mature bone?
Parallel with the osteons' long axis
38
What do you call the functional unit of compact bone?
An osteon
39
Osteocytes have slender cytoplasmic processes called what?
| What is their function?
Canaliculi
| Connect adjacent osteocytes via their gap junctions to allow nutrients to pass between them
40
Spongy (cancellous) bone does not have what structures that compact (cortical) bone does?
Haversian canals
| Volksmann's canals
41
```
Bone is composed of:
65% __________
23% __________
10% _________
2% ___________
```
mineral
type 1 collagen
water
non-collagen protein
42
What features of bone help them to resist fractures?
Great tensile and compressive strength
| Degree of flexibility
43
The lamellae of bone are thought to be able to do what before excessive load causes fracture?
Slip relative to each other
44
What are the 4 stages of bone fracture repair?
1. Haematoma formation
2. Fibrocartilaginous callus formation
3. Bony callus formation
4. Bone remodelling
45
What happens to form the haematoma in the initial stage of bone fracture?
Blood vessels in the bone and periosteum break and a clot forms
46
What happens during stage two of bone fracture repair?
Fibrocartilagenous callus forms
| New blood vessels infiltrate the fracture haematoma
47
The bony callus is made up of what type of bone?
Spongy (Cancellous) bone
48
What type of ossification occurs during the final stages of fracture repair?
Both endochondrial ossification and intramembranous ossification
49
If a fracture involves loss of bone fragments, then what is not possible? What can be done in this case?
Bony callus formation
| Bone graft
50
What is osteoporosis?
A metabolic bone disease in which mineralized bone is decreased in mass to the point that it can no longer provide mechanical support
51
Osteoporosis associated with ageing results from what?
Incomplete filling of bays formed by osteoclasts
52
Osteoporosis is a risk factor for what in the elderly?
Bone fractures
53
Primary osteoporosis exists in two types, what are they?
Type 1: Postmenopausal women, increased osteoclast number as a result os oestrogen withdrawal
Type 2: Elderly individuals, attenuated osteoblast function occuring after the age of 70
54
Name 5 risk factors for osteoporosis
```
Genetics
Insufficient calcium intake
Insufficient calcium absorption and vitamin D
Exercise
Cigarette smoking
```
55
Cartilage is an avascular tissue make up of what?
Extracellular matrix
| Chrondrocytes
56
Cartilage contains a large ratio of what in relation type I collagen which means that it is able to readily diffuse substances between chondrocytes and blood vessels surrounding the cartilage?
Glycosaminoglycans (GAGs)
57
There is a large amount of what substance in the ECM of cartilage which aids its resilience to repeated application of pressure?
Hyaluronic acid
58
A proteoglycan monomer is made up of what?
Approximately 100 glycosaminoglycans joined to a core protein
59
Describe the structure of the cartilage ground substance based on the arrangement of proteoglycan momomers, hyaluronic acid and collagen fibrils
The proteoglycan monomers are attached to hyaluronic acid molecules which form linear aggregates and are interwoven with a network o collagen fibrils
60
What feature of the hyaluronate proteoglycan aggregate enable it to form a hydrated gel?
The high density of negative charges on the GAGs which attracts water
61
Which type of cartilage is the most abundant in the body?
Hyaline cartilage
62
What is the composition of hyaline cartilage?
| In terms of matrix proteins
A matrix containing:
proteoglycans
hyaluronic acid
Type II collagen
The hyaluronate proteoglycan aggregates are bound to the fine collagen matrix fibres
63
What is the composition of elastic cartilage?
A matrix like hyaline cartilage with the addition of many elastic fibres and elastic lamellae
64
What is the composition of fibrocartilage?
The same matrix material of hyaline cartilage with abundant Type I collagen
65
Fibrocartilage is a cross between what and what?
Dermis and hyaline cartilage
66
Hyaline cartilage contains what type of cells?
Only chondrocytes
67
Briefly describe hyaline cartilage development
Chondrocytes form isogenous groups and lay down extracellular matrix as they separate and elaborate
68
In early fetal development hyaline cartilage is the precursor for what? What process creates this?
Bone
| Endochondrial ossification
69
As long bone develops some hyaline cartilage remains where?
At the articulating surface (end of bones)
| At the epiphyseal plate until growing ceases
70
What covers the margin of hyaline cartilage?
Perichondrium
71
What is the perichondrium made up of?
Fibroblast-like cells which can develop into chondroblasts and further develop into chondrocytes
72
The perichondrium is a _______ connective tissue
dense
73
Growth from the periphery is known as what?
Appositional growth
74
Chondrocytes deeper in the cartilage may divide and give rise to isogenous groups which deposit matrix that results in what kind of growth?
Interstitial growth
75
Interstitial growth is growth in ________
Length
76
Appositional growth is growth in _________
Thickness
77
Each chondrocyte lies in a ________. The pleural or this is ________
Lacuna
| Lacunae
78
What will determine how much ECM the chondrocyte lay down?
Forces applied to them (Pressure loads)
79
In developing bones, hyaline cartilage will do what?
Ossify
80
In developing bones, what is there at the non-articulating surfaces that there is a lack of at the articulating surfaces
Perichondrium
81
The end of a long bone is known as the what?
Epiphysis
82
The shaft of a long bone is known as the what?
Diaphysis
83
What is the portion of the bone in-between the epiphysis and diaphysis known as?
Metaphysis
84
Unlike hyaline cartilage, elastic cartilage does not do what with age?
Calcify
85
What cell types are found in fibrocartilage?
Chondrocytes
| Fibroblasts
86
Fibrocartilage is a combination of what?
Dense regular connective tissue and hyaline cartilage
87
There is no ___________ in fibrocartilage
perichondrium
88
Fibrocartilage contains type ___ cartilage which is not found in hyaline and elastic cartilage
Type I
89
What is the name given to the process in which a hyaline cartilage template is replaced by bone
Endochondrial ossification
90
What is the synovial joint?
A moveable joint in which the opposed bone ends are:
- Covered in hyaline cartilage
- Within lubricating synovial fluid bounded by an articular capsule, lined by a synovial membrane and reinforced with fibrous tissue and ligaments
91
The synovial membrane consists of what cells which remove debris from the joint space?
Macrophages
92
Which cells are responsible for secreting synovial fluid in the synovial joint?
Fibroblast-like cells
93
The fibrous capsule of the synovial joint is continuous with what structure of bone?
Periosteum
94
What is the difference between osteoporosis and osteomalacia?
Osteoporosis is loss of bone density whereas osteomalacia is loss of bone mineral leading to softening of the bone
