Connective tissue Flashcards
(140 cards)
1
Q
What is ground substance?
A
A basic tissue that provides structural and metabolic support to other tissues and organs.
2
Q
What does Ground substance add?
A
Strength and stiffness
3
Q
What does Ground substance delay?
A
Delays the spread of infection
4
Q
Ground substance characteristics
A
Gel-like extracellular matrix
5
Q
What does Ground substance contain (x 3) ?
A
- Water (and salts)
- Glycosaminoglycans (GAGs)
- Proteoglycan molecules
6
Q
What are glycosaminoglycans?
A
Polysaccharides, made up of sugar
7
Q
What do proteoglycan molecules do?
A
Bind water giving gelatinous property to matrix
8
Q
What do proteoglycan molecules form?
A
They form aggregates to make up ground substance.
9
Q
What is the main component of ground substance?
A
Glycosaminoglycans
10
Q
Most common glycosaminoglycans?
A
- Hyaluronate
- Chondroitin-4-sulphate
- Chondroitin-6-sulphate
- Dermatan sulphate
- Heparin sulphate
- Keratin sulphate
11
Q
What is the predominant GAG?
A
Hyaluronic acid
12
Q
🥲What is hyaluronate so important in GAGs?
A
Because the viscosity of ground substance depends on the content of it.
13
Q
How does GAGs stain?
A
Metachromatically with toluidine blue
14
Q
🥲What is the ground substance elaborated by?
A
Endoplasmic reticulum, especially of fibroblast.
15
Q
🥲What are the most important connective tissue cells?
A
- Mesenchymal cells
- Fibroblasts
- Adipocytes (fat cells)
- Immune cells
- Macrophages / Monocyte
- Mast cells
- B cell / Plasma cells
- Lymphocyte
16
Q
What are the most important connective tissue fibres?
A
- Collagen
- Elastin
17
Q
Inter-relationship of Connective tissue
A
- All have one ancestor - mesenchymal stem cell
- All cells have diversity in form and function
- Evidence that interchange is possible
18
Q
Function of Mesenchymal stem cells (MSCs)
A
To differentiate into other cells
19
Q
Function of fibroblasts
A
Synthesis extracellular matrix; would healing
20
Q
Function of adipocytes (fat cells)
A
Store and metabolise fat
21
Q
Function of macrophages (Histiocytes)
A
Phagocytic, innate immune cell
22
Q
Function of mast cells
A
Histamine reactions; innate immune cell
23
Q
Function of B cells / Plasma cells
A
Make antibodies; adaptive immune cell
24
Q
Function of T cells
A
Major immune cell; adaptive immune cell
25
Where are mesenchymal stem cells obtained from?
Bone marrow
26
What can mesenchymal stem cells do?
Differentiate into all other cells in connective tissue
27
What type of stem cells are mesenchymal stem cells?
Multipotent
28
What do mesenchymal stem cells have potential for?
Cell replacement therapy
29
What is the most abundant cell in connective tissue
Fibroblasts
30
What do fibroblasts have a role in?
Would healing (secrete collagenous matrix - scar tissue)
31
Name two cell thats can differentiate into other cells.
Mesenchymal stem cells & fibroblasts
32
What do fibroblasts synthesise?
Extracellular matrix, i.e secrete components (GAGs, collagen, elastin, ground substance)
33
What do adipocytes develop from?
Fibroblasts
34
What do adipocytes do (x 3)?
- Store & metabolise fat (lipids)
- Insulate
- Support and protect organs
35
Can mature adipocytes divide?
No
36
Role of white adipose
Energy store - insulation & shock absorption
37
Role of brown adipose
Stores energy in fat
38
White adipose percentage of body weight
20% males, 25% females
39
Where is a macrophage born?
In bone marrow
40
The birth of macrophage stages
1. Stem cell - bone marrow
2. Monoblast - bone marrow
3. Monocyte - blood
4. Macropage - tissue
5. Activated macrophage - tissue
41
What do macrophages present at their surface?
Present pathogen antigens at their cell surface to T cells (elicit an adaptive immune response)
42
Where are fixed macrophages found at?
Strategic points
43
What are the roles in disease of macrophages?
- role in atherosclerotic deposits
- destroy influenza infected throat cells
- they release growth factors (tumor cell proliferation)
44
The replication of what virus occurs in macrophages?
HIV
45
What historical pathogen was resistant to phagocytosis?
The plague pathogen
46
Name 3 disorders of macrophages
- Granuloma
- Macrophage Activation Syndrome
- Multicentric reticulohistiocytosis
47
Name two disease are resistant to lysosomal degradation.
- Leprosy
| - Tuberculosis
48
What do macrophages have for degradation?
Lysosomes
49
What do macrophages do to foreign materials?
They scavenge foreign materials
50
What are two types of mast cells?
- Connective tissue type
| - Mucosal
51
5 places mast cells present?
- Skin
- Mucosa of lungs
- Gut
- Mouth
- Nose
52
What does mast cells stimulate?
Stimulates release of histamine and heparin
53
What does histamine do?
Dilates venules, activates endothelium, and increases blood vessel permeability
54
What do mast cells cause (symptoms)?
Causes edema (swelling), warmth, redness, attracts inflammatory cells, activates nerves (itching & pain)
55
What are mast cells similar to?
Basophils
56
What do mast cells express
Fc receptor
57
What do B-cells express?
‘immunoglobulin-receptors’ on surface membrane
58
What do B-cells bind?
Bind to receptors & induce B-cell differentiation into plasma and memory cells
59
Are memory cells short or long lived?
Long lived
60
What do memory cells allow for?
Allow quick attack against same antigen
61
What do plasma cells produce?
Antibodies
62
Where are plasma cells usually found?
Tissues – lymph nodes, spleen, intestine
63
Function of antibodies
- Block entry of viruses by binding viral surface
| - Coat antigen on pathogens and facilitate phagocytosis by macrophages
64
Four types of T-cells
- Helper T cells
- Cytotoxic T cells
- Suppressor T cells
- Memory T cells
65
Function of Helper T cells
Secrete interleukins to activate B cell, cytotoxic T cell & macrophage
66
Function of Cytotoxic T cells
Kill virus infected cells & some cancer cells
67
Function of Suppressor T cells
Suppress response to self antigens
68
Function of memory T cells
Long lived activated T cells that remain for subsequent activation (i.e. adaptive)
69
Antigen presenting cells
- Infected macrophage
- B-cell
- Dendritic cell
- Tumour cell
70
What does T cell expressing T-cell receptor bind?
Binds antigen-MHC complex to become activated
71
Where is digested foreign material presented?
At the cell surface attached MHC (major histocompatibility complex)
72
3 types of fibres
- Collagen
- Elastin
- Fibrillin
73
What are collagen, elastin and fibrillin synthesised by?
Collagen
74
What type of fibres does collagen make?
Log straight fibres
75
What is the most common fibre in connective tissue?
Collagen
76
Where is collagen present?
Found in skin, tendons, ligaments, bone and organs
77
Collagen weak / strong
Flexible and strong
78
Fibroblasts (synthesise)→
Collagen proteins (aggregate) →
79
Collagen proteins (aggregate) →
Tropo-collagen (assemble) →
80
Tropo-collagen (assemble) →
Collagen microfibrils fibres (form) →
81
Collagen microfibrils fibres (form) →
Collagen bundles
82
Fibroblasts (synthesise)→ (full)
Collagen proteins (aggregate) → Tropo-collagen (assemble) → Collagen microfibrils fibres (form) → Collagen bundles
83
What dictates the type of collagen fibres?
Their structural role in a particular organ
84
Give 4 examples of collagen fibres
- Gel
- Tight bundles
- Stacked
- Fibres arranged at an angle
85
Where are gel collagen fibres present?
Extracellular matrix or vitreous humor of eye
86
Where are tight bundle collagen fibres present?
Tendons
87
Where are stacked collagen fibres present?
Cornea
88
Where are collagen fibres arranged at an angle present?
Bones
89
What are polypeptide chains held together by?
Hydrogen bonds
90
What are fibril-forming collagen types?
I - III
91
Where is collagen type I present?
- Found in the supporting elements of high tensile strength.
| - Found in bone, skin, tendon, muscles, cornea and walls of blood vessels.
92
Where is collagen type II present?
- In cartilaginous tissues,
- Inter vertebral disk
- Vitreous body
- Hyaline cartilage.
93
Where is collagen type III present?
Found in distensible tissues, tissues that can expand due to pressure from within - fetal skin, blood vessels.
94
What are network-forming collagen types?
IV & VII
95
Where is collagen type IV found?
Found in the basement membranes and muscles.
96
Does collagen type IV form fibrils?
No
97
What is the structure of collagen type IV like?
mesh-like
98
Where is collagen type VII found?
Beneath stratified squamous epithelia
99
What does collagen type VII form?
Forms anchoring fibrils that link to the basemen membrane.
100
What are the fibril-associated collagen types?
IX and XII
101
Where is collagen type IX found?
In cartilage
102
Where is collagen type IX localised?
At intersections of cartilage fibres
103
Where is collagen type XII found?
- Tendons
| - Ligaments
104
Collagen tumors
Fibrosarcoma
105
Function of fibrosarcoma
Proliferating fibroblast tumor
106
Systemic disorders (connective fibre related)
Systemic lupus Erythematosus (SLE)
107
Function of Systemic lupus Erythematosus (SLE)
Autoimmunity against connective tissue
108
Inherited disorders (connective fibre related) (5)
- Ehlers–Danlos syndrome
- Osteogenesis Imperfecta
- Marfan syndrome
- William’s syndrome
- Cutis laxa
109
Function of Ehlers–Danlos syndrome
Mutation in gene coding collagen
110
Function of Osteogenesis Imperfecta
Mutation in collagen synthesis
111
Function of Marfan syndrome
Mutation in gene coding fibrillin
112
Function of William’s syndrome
Deletion of gene coding elastin
113
Function of Cutis laxa
Mutation in gene coding elastin
114
Dysfunctional collagen synthesis
Keloid Hypertrophy
115
Function of keloid hypertrophy
Collagen hypergrowth on scars
116
Fibrosarcoma most common age/gender
Males aged 30-40 years.
117
What can fibrosarcoma form from?
From fibroblasts in soft tissue
118
What is fibrosarcoma?
An overgrowth of tissues with an excess deposition of matrix components (i.e. collagen) by proliferating fibroblasts
119
When does Systemic Lupus erythematosus start
Age 15-50
120
Survival rate of Systemic Lupus erythematosus
95% (5yr), 90% (10yr) and 78% (20yr)
121
What happens in Systemic Lupus erythematosus?
Immune system self-attacks connective cells
122
Systemic Lupus erythematosus gender
More likely in non-European women
123
Symptoms of Systemic Lupus erythematosus
```
95% Achy joints (arthralgia)
90% Fever over 38ºC
81% Prolonged or extreme fatigue
90% Arthritis (swollen joints)
74% Skin Rashes
71% Anaemia
50% Kidney Involvement
45% Chest Pain on deep breathing (pleurisy)
30% Sun or light sensitivity (photosensitivity)
27% Hair loss
17% Raynaud's phenomenon (fingers blue)
15% Seizures
12% Mouth or nose ulcers.
```
124
Ehlers - Danlos syndrome
- Mutation gene coding collagen
- Hypermobility of joints
- Stretchy skin
125
Osteogenesis imperfecta is a mutation in..
Collagen synthesis
126
What does osteogenesis affect?
Skeleton ears and eyes
127
What is osteogensis also known as?
Brittle bone disease
128
What is marfan syndrome a mutation in?
In gene coding fibrillin
129
What does marfan syndrome affect?
- Eysight
- Lungs
- Heart
- Skeleton
130
How is eyesight affected by marfan syndrome?
- Near-sighted (myopic)
- Ocular lens dislocation
- Retinal detachment
131
How are lungs affected by marfan syndrome?
Spontaneous lung collapse (pneumothorax)
132
How is the cardio-vascular system affected by marfan syndrome?
- Aorta widening / dilatation
- Aortic aneurysms
- Mitral and aortic valve proplapse / leakage
133
How is the skeleton affected by marfan syndrome?
- Scoliosis
- Pectus deformity
- Tall stature
- Loose jointedness
134
Two syndromes resulting from mutations in elastin
- William's syndrome
| - Cutis Laxa
135
Cutis Laxa physical effect
Skin hangs loosely in folds
136
What is cutis laxa a mutation in?
In elastic fibres comprising the dermis
137
What is deletion elastin associated with?
With connective tissue issues
138
What are behavioural characteristics of people with William's syndrome?
Distinctive, cheerful manner & ease with strangers
139
What is William's syndrome?
A rare neurodevelopmental disorder
140
Deletion of William's syndrome
26 genes on chromosome 7
