Introduction to Immune System Flashcards
1
Q
What are examples of barrier against foreign pathogens?
A
- Physical
- Mucosal membranes
- Mucociliary escalator
- Skin
- Chemical
- Acidic pH of stomach
- Rapid pH change in duodenum and alkaline pH in jejunum and ileum
- Skin sebum to lower pH
- Lyzozymes (anti-bacterial enzyme) in tears, saliva and sweat
2
Q
Describe the anatomy of the immune system?
A
Formed from
- Lymphoid organs
- Bone marrow
- Spleen
- Lymph nodes
- Mucosal membranes
- Mucosa-associated lymphoid tissue (LALT)
- Bronchus-associated lymphoid tissue (BALT)
- Gut-associated lymphoid tissue (GALT), including Peyer’s patches
3
Q
What are the lymphoid organs?
A
- Bone marrow
- Spleen
4
Q
What mucosal membranes contribute to the immune system?
A
- Mucosa-associated lymphoid tissue (LALT)
- Bronchus-associated lymphoid tissue (BALT)
- Gut-associated lymphoid tissue (GALT), including Peyer’s patches
5
Q
What are the cells of the immune system derived from?
A
Formed in bone marrow from multipotential haematopoietic stem cell (haemocytoblast)
6
Q
What cells form the immune system?
A
-
Megakaryocyte
- Location – bone marrow
- Structure – lobulated nucleus
- Function – production of platelets
- Life span – 7 to 10 days
-
Platelets
- Location – bone marrow and circulation
- Structure – small anucleate disc shaped cell fragments with granules
- Function – blood clotting
- Life span – 7 to 10 days
-
Erythrocyte
- Location – bone marrow and circulation
- Structure – biconcave and anucleate
- Function – transport oxygen, damaged RBC removed via reticuloendothelial system
-
Mast cell
- Location – connective tissues and mucous membranes
- Structure – large granulocyte, granules contain histamine
- Function – important role in allergy, main cell targets are parasites, activated by cross linking of IgE antibodies bound to their FC receptors, activation resulting in degranulation
- Life span – few weeks to months
-
Basophil
- Location – bone marrow and circulation
- Structure – granulocyte, granules contain histamine
- Function – main target parasites, activated by cross-linking of IgE antibodies that they have bound to their FC receptors, activation results in degranulation, also capable of phagocytosis
- Life span – hours to days
-
Neutrophil
- Location – bone marrow and circulation
- Structure – granulocyte, granules contain substances to kill and digest pathogens such as peroxidase
- Function – first cells to migrate to site of infection, target is extracellular pathogens like bacteria and fungi, perform phagocytosis or degranulation
- Life span – few days
-
Eosinophil
- Location – bone marrow and circulation, tissues such as lungs and oesophagu
- Structure – granulocyte, granules contain substances to digest and kill pathogens such as peroxidase
- Function – targets multicellular parasites too big for phagocytosis, important role in allergy
- Life span – 8 to 12 days
-
Monocyte
- Location – bone marrow and circulation
- Structure – kidney shaped nucleus
- Function – migrates to tissue where they become macrophages and dendritic cells in response to inflammation, capable of phagocytosis, large quantities of hydrolytic enzymes
- Life span – 24 hours
-
Macrophage
- Location – bone marrow and are tissue-based progeny of monocytes, name changes depending on what tissue in
- Function – phagocytosis, antigen presenting cell to CD4+ Th cells, cytokine release (TNF-alpha, IL-2, IL-6)
- Life span – months to years
-
Dendritic cell
- Location – tissues exposed to external environment
- Structure – long narrow processes which resemble neuronal dendrites
- Function – antigen presenting cell to CD4+ T cells via MHC II, phagocytosis, cytokine secretion (TNF-alpha, IL-12, IL-23)
- Life span – days to weeks
-
Natural killer cell
- Location – bone marrow, circulation and spleen
- Structure – large granular lymphocyte, granules contain special proteins such as perforin and proteases
- Function – activated by IFN and macrophage derived cytokines, or activated by abnormal MHC I signals (cancerous cells or virally infection cells) to cause apoptosis of cell
-
T-lymphocyte
- Location – completes maturation in thymus, mature T cells reside in bone marrow, circulation and places such as lymph nodes
- Structure – all T cells express T cell receptors on their cell surface, there are 3 types: Helper T cells (CD4+), Cytotoxic T cells (CD8+) and Regulatory T cells (CD4+, CD25+)
- Function – involved in cell mediated adaptive immune response
-
B-lymphocyte
- Location – completes maturation within lymph nodes and spleen, mature B cells reside in bone marrow, circulation and lymph nodes
- Structure – all B cells express B cell receptors on surface, 2 kinds: plasma B cells and memory B cells
- Function – involved in humoral mediated adaptive immune response by producing specific antibodies against certain antigens
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7
Q
For megakaryocyte:
- location
- structure
- function
- life span
A
- Megakaryocyte
- Location – bone marrow
- Structure – lobulated nucleus
- Function – production of platelets
- Life span – 7 to 10 days
8
Q
For platelets:
- location
- structure
- function
- life span
A
- Location – bone marrow and circulation
- Structure – small anucleate disc shaped cell fragments with granules
- Function – blood clotting
- Life span – 7 to 10 days
9
Q
For erythrocyte:
- location
- structure
- function
A
- Location – bone marrow and circulation
- Structure – biconcave and anucleate
- Function – transport oxygen, damaged RBC removed via reticuloendothelial system
10
Q
For mast cell:
- location
- structure
- function
- life span
A
- Mast cell
- Location – connective tissues and mucous membranes
- Structure – large granulocyte, granules contain histamine
- Function – important role in allergy, main cell targets are parasites, activated by cross linking of IgE antibodies bound to their FC receptors, activation resulting in degranulation
- Life span – few weeks to months
11
Q
For basophil:
- location
- structure
- function
- life span
A
- Basophil
- Location – bone marrow and circulation
- Structure – granulocyte, granules contain histamine
- Function – main target parasites, activated by cross-linking of IgE antibodies that they have bound to their FC receptors, activation results in degranulation, also capable of phagocytosis
- Life span – hours to days
12
Q
For neutrophil:
- location
- structure
- function
- lifespan
A
- Neutrophil
- Location – bone marrow and circulation
- Structure – granulocyte, granules contain substances to kill and digest pathogens such as peroxidase
- Function – first cells to migrate to site of infection, target is extracellular pathogens like bacteria and fungi, perform phagocytosis or degranulation
- Life span – few days
13
Q
For eosinophil:
- location
- structure
- function
- life span
A
- Eosinophil
- Location – bone marrow and circulation, tissues such as lungs and oesophagu
- Structure – granulocyte, granules contain substances to digest and kill pathogens such as peroxidase
- Function – targets multicellular parasites too big for phagocytosis, important role in allergy
- Life span – 8 to 12 days
14
Q
For monocyte:
- location
- structure
- function
- life span
A
- Location – bone marrow and circulation
- Structure – kidney shaped nucleus
- Function – migrates to tissue where they become macrophages and dendritic cells in response to inflammation, capable of phagocytosis, large quantities of hydrolytic enzymes
- Life span – 24 hours
15
Q
A