Blood 2 Flashcards
(155 cards)
1
Q
What are the three major mechanisms of defense?
A
- Protective surfaces
- Innate immune system
- Adaptive immune system
2
Q
What are the functions of protective surfaces?
A
- Secrete antibacterial substance (lysozyme)
- Have acidic pH that inhibits growth of pathogens
3
Q
What are the protective surfaces?
A
• Skin • Mucosal linings - Gastrointestinal tract - Respiratory tract - Urinary tract - Reproductive tract
4
Q
What is the function of innate immune cells
A
- Complement protein & peptides in blood/tissue
- Beat trivial infections
5
Q
NB! What are the innate immune cells in blood/tissue? (6)
A
(1) Neutrophils
(2) Eosinophils
(3) Basophils
(4) M’cyte/Macrophage
(5) Mast cells
(6) Natural killer cells
6
Q
What are adaptive immune cells?
A
Cells with ability to learn i.e. subsequent infections produce greater response
7
Q
What are two adaptive immune cells?
A
- T lymphocytes (T cells)
- B lymphocytes (B cells)
8
Q
What is the response of T lymphocytes?
A
Cellular response
9
Q
What is the response of B lymphocytes?
A
Humoral response
10
Q
What do T cells interact with?
A
APCs (macrophage & dendritic cells)
11
Q
What is involved in B cells?
A
- Involves production of antibodies by B cells
12
Q
What are the components of blood?
A
- Red blood cells (erythrocytes)
- Platelets
- White blood cells (leukocytes)
- Plasma
13
Q
What are white blood cells composed of?
A
- Granulocytes (neutrophils, eosinophils, basophils)
- Agranulocytes (lymphocytes, monocytes)
14
Q
What is the function of phagocytosis?
A
- To acquire nutrients
- To remove pathogens & cell debris
15
Q
What are the steps in phagocytosis?
A
- Engulf by endocytosis
- Form an internal phagosome
- Delivered & fusion with lysosome
- Degraded in lysosome
- Released via exocytosis
16
Q
What are the three types of leukocytes (granulocytes)?
A
- Neutrophil
- Eosinophil
- Basophil
17
Q
What is the diameter of neutrophils?
A
10-12µm
18
Q
What is the diameter of eosinophils?
A
10-14µm
19
Q
What is the diameter of basophils?
A
8-10µm
20
Q
What is the % of WBCs of neutrophils?
A
60-70%
21
Q
What is the % of WBCs of eosinophils?
A
1-5%
22
Q
What is the % of WBCs of basophils?
A
1-5%
23
Q
What is the primary function of neutrophils?
A
1st to encounter pathogens
24
Q
What is the primary function of eosinophils?
A
Attack parasites e.g. worms
25
What is the primary function of basophils?
Release heparin, elastase
26
What is the nucleus of neutrophils composed of?
Composed of 2-5 lobes
27
What are 3 functions of neutrophils?
- Acute inflammation
- First line of defence during infection
- Phagocytic activity
28
What do primary neutrophils contain?
Contain antibacterial and digestive enzymes (eg myeloperoxidase) involved in destruction of invading organisms
29
What do secondary neutrophils contain?
Contain lyzozymes; involved in phagocytosis
30
What do tertiary neutrophils contain?
Contain gelatinase; granules involved in insertion of glycoproteins into cell membrane for cellular adhesion
31
What is the type of nucleus in eosinophils?
Bilobed nucleus
32
Where do eosinophils enter?
Enter mucosal surfaces of respiratory, lower urinary
| and GI tracts
33
When are eosinophils increased?
Increased in parasitic allergic disease
34
What do eosinophils phagocytose?
Phagocytose IgE opsonised parasites
35
How do eosinophils kill?
By granule release
36
What are the characteristics of basophils?
Large granules (basophilic, dark blue staining & bilobed nucleus
37
What are basophils similar to?
Mast cells
38
What do basophils contain?
Histamine
39
What is the function of histamine?
Dilates blood vessels (inflammation-redness)
40
When are basophils increased?
In parasitic/allergic disease
41
What do basophils exocytose? (and via what?)
Exocytose granules (histamine) via contact with IgE complexed allergen
42
What % of WBC are lymphocytes?
20%
43
What do lymphocytes cooperate with?
With antigen presenting cells (APCs)
44
What are two types of lymphocytes?
B-lymphocytes (B cells)
| T-lymphocytes (T cells)
45
What is the function of B-lymphocytes?
Antibody production (plasma cells) antigen presentation
46
What is the function of T-lymphocytes?
- Priming of innate responses (T-helper 1, TH1)
- Priming of antibody responses (T-helper 2, TH2)
- Direct cell lysis (cytotoxic T’s)
47
What % of WBC are monocytes?
5%
48
What are monocytes attracted by?
- Histamine
| - Cytokines
49
Birth etc of monocytes
Emerge from bone marrow while immature; 1-2 days later mature into macrophages
50
How long do macrophages last?
For months
51
What do macrophages do before they die?
Digest 100’s bacteria before they die
52
What do macrophages present?
Present pathogen antigens at cell surface
53
Where are fixed macrophages stationed?
At strategic points
54
What are the types of fixed macrophages?
1. Dust/Alveolar type (lungs)
2. Histiocytes (connective tissue)
3. Kupffer cells (liver)
4. Microglial cells (nervous)
5. Osteoclasts (bone)
6. Sinusoidal lining cells (spleen)
55
What are the characteristics of erythrocytes?
Biconcave, anucleate dics; salmon-colored; diameter 7-8µm
56
Erythrocyte cellss/mm3 of blood.
4-6 million
57
Duration of development of erythrocytes.
5-7 days
58
Life span of erythrocytes
100-120 days
59
Function of erythrocytes
Transport oxygen and carbon dioxide
60
Description of leukocytes
Spherical, nucleated cells
61
Leukocytes cellss/mm3 of blood.
4800-10,800
62
Description of neutrophil
Nucleus multilobed; inconspicuous cytoplasmic granules; diameter 10-12µm
63
Neutrophils cellss/mm3 of blood.
3000 - 7000
64
Duration of development of neutrophils.
6-9 days
65
Life span of neutrophils
6 hours - few days
66
Function of neutrophils
Phagocytize bacteria
67
Description of eosinphils
Nucleus bilobed; red cytolasmic granules; diameter 10-14µm
68
Eosinophil cellss/mm3 of blood.
100-400
69
Duration of development of eosinophils
6-9 days
70
Life span of eosinophils
8-12 days
71
Function of eosinophils
Kill parasitic worms; destroy antigen-antibody complexes; inactivate some inflammatory chemical of allergy
72
Function of basophils
Release histamine and other mediators of inflammation; contain heparin, an anticoagulant
73
Function of lymphocytes
Mount immune response by direct cell attack or via antibodies
74
Function of monocyte
Phagocytosis; develop into macrophages in tissues
75
Function of platelets
Seal small tears in blood vessels; instrumental in blood clotting
76
What do mast cells express?
Express Fc receptor
77
What do mast cells bind?
Binds Fc of IgE
| made by B-cells
78
What do allergens bind?
Bind IgE on mast cell surface
79
What do mast cells stimulate?
Stimulates release of histamine and heparin
80
What is the function of histamine?
Dilates venules increasing blood permeability
81
What does histamine cause (symptoms)?
Edema (swelling), warmth, redness, attracts inflammatory cells, activates nerves (itching & pain)
82
What type of cells are natural killer cells?
Cytotoxic lymphocytes
83
What is cytotoxic activity controlled by?
By surface expressed "activating receptors" and "inhibitory receptors“
84
What are patients deficient in natural killer cells susceptible to?
Herpes virus infection
85
What do natural killer cells release?
Perforin
86
What is the function of perforin?
Form pores in cell membrane and causes apoptosis
87
What do natural killer cells play a role in?
In rejection of tumors and cells infected by viruses
88
Disease of neutrophil
Neutropenia - (low numbers) during anemia, leukemia, chemotherapy, which results in increased infections
89
Diseases of eosinphils
- Eosinopenia
| - Eosinophilia
90
Eosinopenia
Low numbers - during stress, glucocorticoid treatment, Cushing's disease
91
Eosinophilia
high numbers - during infection, arthritis, malignancy, dermatitis, drugs (penicillin)
92
Diseases of basophils
- Basopenia
| - Basophilia
93
Basopenia
Low numbers - causes itching (autoimmune urticaria)
94
Basophilia
High numbers - in some forms of leukaemia or lymphoma
95
Where does HIV virus replicate?
In macrophages
96
What was plague pathogen resistant to?
To phagocytosis by macrophages
97
What do macrophages release?
Tumour growth molecules
98
What are leprosy and tuberculosis resistant to?
To lysosomal degradation by macrophages
99
What do macrophages destroy?
Influenza infected cells
100
What diseases do mast cells release histamine in?
Asthma, Arthritis, Eczema, Itch, Rhinitis, Anaphylaxis.
101
What do B cells express?
‘immunoglobulin-receptors’ on surface membrane
102
What do B-cells differentiate into?
into plasma/memory cells
103
What do memory cells allow for?
Allow quick attack against same antigen (vaccination principle) – (ie adaptive)
104
What do plasma cells produce?
Antibodies specific for antigens
105
Where are plasma cells usually found?
In lymph nodes, spleen, intestine, etc
106
What is the function of antibodies? (3)
* Block entry of viruses by binding viral surface
* Coat antigen on pathogens
* Facilitate phagocytosis by macrophages
107
What are antibodies composed of?
– Two Heavy chains
| – Two light chains
108
What do the light and heavy chains of antibodies do?
Come together to form a specific antigen binding site
109
What do all antibodies eventually do?
Enter the blood
110
What are antibodies known as in the blood?
Gamma globulins or immunoglobulins
111
What are the antibody (Immunoglobulin) subclasses?
- IgM
- IgG
- IgE
- IgA
- IgD
112
Function of IgM
Serves as the β cell surface receptor for antigen attachment
113
When is IgM secreted?
Secreted in early stages of plasma cell response
114
What is the most abundant immunoglobulin in blood?
IgG
115
When is IgG produced (amount)?
Produced in large amounts when body is exposed to same antigen
116
Function of IgE
- Helps protect against parasitic worms
| - Antibody mediator for common allergic responses
117
Where is IgA found?
Found in secretions of digestive, respiratory, and genitourinary systems; also in milk and tears
118
Where is IgD present?
Present on surface of many β cells
119
What are the four types of T-cells?
- Helper (Th)
- Cytotoxic (Tc)
- Suppressor (Ts)
- Memory
120
Function of helper T-cells
Secrete interleukins
121
Function of cytotoxic T-cells
Kill virus infected cells & cancer cells
122
Function of suppressor T-cells
Suppress response to self antigens
123
Function of memory T-cells
Long lived (i.e. adaptive)
124
4 Antigen presenting cells
* infected macrophage
* B-cell
* dendritic cell
* tumor cell
125
Where is digested foreign materal presented?
At the cell surface attached MHC (major histocompatibility complex)
126
What do T cell expressing T-cell receptor (TCR) bind?
Binds antigen-MHC complex to become activated
127
Process of cytotoxic T-cells killing
1. Class I MHC molecules are found on surface of all cells.
2. They are recognized only by cytotoxic (CD8) T cells.
3. CD8 coreceptor links the two cells together.
4. Linked in this way, cytotoxic T cells can destroy body cells if invaded by foreign (viral) antigen.
128
Functions of lymphoid tissue (3)
1. Produce, store and distribute lymphocytes
2. Return interstitial fluid to blood
3. Transport lipids and lipid-soluble vitamins
129
6 Secondary lymphoid tissues
```
– Spleen
– Lymph nodes
– Gut-associated lymphoid tissue (GALT) [Peyer’s
Patches]
– Adenoids
– Appendix
– Tonsils
```
130
What is the site of T cell development?
Thymus
131
What is the site of B-cell and pre T cell development?
Bone marrow
132
Components of the lymphatic system
Lymphocytes, Lymph, Lymphatic vessels
133
Primary lymphoid tissues and function
* Thymus where immature T-cell mature
| * Bone marrow where lymphocyte stem cells & Bcells mature
134
Secondary lymphoid tissues
- Spleen
- Lymph nodes
- MALT/GALT
135
What occurs in the spleen (involving cells_
Where T- & B-cells interact with antigens in blood
136
Where are lymph nodes found?
At large lymphatic vessels
137
What occurs at lymph nodes?
Where T- and B-cells are activated by antigen/APC activation)
138
What is at mucosal/gut associated lymphoid tissue
Lymphatic clusters e.g. Tonsils, Peyer’s patches in intestine
139
What does the thymus have?
Cortex and medulla
140
What do epithelial cells in outer cortex of thymes secrete? (and promote)
Nurse cells secrete hormones and promote T-cell differentiation and proliferation
141
What do T cells move deeper towards?
medulla
142
What do T cells acquire on surface?
Acquire TCR on surface
143
What are T-cells activated and destroyed by?
Activated by self-antigens are destroyed by apoptosis
144
What does the central medulla in the thymus have and function?
Have APCs which exposes T-cells to self antigens
145
Function of lymph nodes
Free antigens and dendritic cells present antigens to T cells
146
What do stimulated B and T cells undergo?
Clonal expansion and maturation
147
Why do lymph nodes become enlarged?
Due to infection (pharyngitis, TB) & tumours (lymphoma, leukaemia, malignant / metastasis)
148
T and B cells when stimulated function
* B cells secrete antibodies
| * T cells leave node & go to damaged tissue
149
Afferenet lymphatic nodes function
Brings, antigen-carrying dendritic cells, macrophages & free antigens
150
Efferenet lymphatic nodes function
Joins blood stream via thoracic duct or lymphatic duct
151
What does lymph draining back into blood pass through?
Lymph nodes
152
Medulla (inner) of lymph nodes contents
contains plasma cells & macrophages
153
Cortex (outer) of lymph nodes contents
Contains lymphocytes (T- & Bcells) and dendritic cells
154
How mat litres of blood not reabsorbed in capillaries / venules.
3 litres
155
Journey of lymphatic drainage.
- Enters lymph vessels
- Pumped to lymph nodes
- Re-enters circulation near right atrium
