1.01 - Introduction To Immunology Flashcards
What are the three components of the immune system?
Organs & Tissues
Cells
Molecules
What are the two types of Lymphoid organs?
Primary
Secondary
Describe Primary Lymphoid organs
Include the Thymus and Bone marrow
Responsible for the production of immune cells
Describe secondary lymphoid organs
Include: Lymph nodes, tonsils, adenoids, spleen & mucosal-associated lymphoid tissue (MALT; including Peyer’s patches in the small intestine)
They are specialised areas in which interactions between various parts of the immune system can be carried out
Where are T cells formed?
Thymus
Describe the Bone Marrow?
Major function is production of all blood cells including important components of the immune system.
Where are B-Cells formed?
Bone Marrow
Describe Lymph Nodes
Nodular aggregates of lymphoid tissues located along lymphatic channels throughout the body.
As lymph passes through the node, APCs in the nodes are able to sample the antigens of microbes or dendritic cells that have picked up antigen peripherally bring them to the nodes.
End results is accumulation of antigens in the node.
Consists of a Paracortex (T cell zone), Follicles (B cell zone) & Germinal centres (where T & B cells communicate)
Describe the Spleen
An abdominal organ that serves the same role in immune responses as that of lymph nodes but to blood-borne antigens. Macrophages and DCs trap the antigen in the spleen.
Spleen contains abundant macrophages which ingest and destroy microbes in the blood
Describe the Lymphatic System
Term that includes lymphatic vessels and lymph nodes
Lymph nodes are like relay stations of the immune system and places in which the components of the immune system interact
Lymphatic vessels form a network of drainage vessels with some smooth muscle and valves, flow largely driven by tissue pressure
Afferent vessels flow towards, efferent vessels flow away from lymph nodes
Drain excess fluid, important for lipid absorption from the gut
Compare the Innate and Adaptive Immune System with respect to:
- Presence in higher organisms
- Specificity of receptors
- Genetics behind the receptors
- Presence of memory
Innate
- Present in earlier organisms
- Relies on receptors and molecules that recognise specific patterns on pathogens
- Structure of receptors and molecules encoded in the germline and is the same for all humans
- Induce the same response the first and 100th time they recognise their pathogen
Adaptive
- Only present in higher vertebrates (arisen through evolution)
- Relies on unique receptors on lymphocytes to identify specific pathogens
- Everyone has lymphocytes with different receptors and they are unique to each person
- Remembers past pathogens and gives a faster and better response with repeated challenges (memory)
Describe the basic interaction of the adaptive and innate immune responses to infection
Pathogen → Activation of the innate immune system → Activation of the adaptive immune system → Activation of the effector functions of both the innate and adaptive immune system
What classes of molecules do Pathogen Recognition Receptors recognise?
Pathogen Associated Molecular Patterns (PAMPs)
Danger Associated Molecular Patterns (DAMPs)
What is an Antigen?
Any molecule recognised by a component of the immune system
Can be a surface protein, secreted toxin, RNA/DNA
Can also be found in host cells infected with a virus, tumour cells and normal host cells
What is the role of Professions Antigen Presenting Cells (APCs)?
To take up bacteria, process them and present the antigen(s) to the rest of the immune system
