Immunity Flashcards
What are innate defences (non-specific resistance)
Responds to a range of pathogens or foreign substances
What are the barriers in the body’s first line of defence?
Mechanical Barriers - skin & mucous membranes
Chemical barriers - stomach acid & lysozyme
What are the barriers in the body’s second line of defence?
Antimicrobial proteins Natural killer cells Phagocytes Inflammation Fever
How is the body’s adaptive defences characterised?
Specificity (each invading agent is different from each other)
Memory (second response is faster and greater than the first)
What does the term ‘non-self’ mean?
Invading antigens are recognised as being non-self.
Specific resistance is carried out by lymphocytes.
Once mature, the lymphocytes acquire specific antigen receptors that allow them to recognise a specific invading agent
What are the two types of lymphocytes?
B cells
T cells
What are B cells?
Developed in the red bone marrow. Once stimulated by an antigen, B cells clone and the become plasma cells.
Plasma cells produce antibodies known as immunoglobulins
What are the 5 classes of antibodies?
IgG IgA IgM IgE IgD
What are T cells?
T cells leave the bone marrow and migrate to the thymus to complete their development.
T cells are involved in cell mediated immune responses
What are cell mediated immune responses directed against?
Intracellular pathogens such as viruses, cancer cells and tissue transplants
How do T cells work in the immune system?
T cells become killer T cells that directly attack the invading antigen, or become helper T cells that help both the antibody and cell mediated responses
What are memory cells?
Memory cells have ‘memory’ of an invading antigen. This memory allows for the second response to be much quicker and greater
What is a primary response?
A primary response is slow and ineffective.
Signs and symptoms of the disease are seen.
What is a secondary response?
Secondary responses are much faster and greater (thanks to memory cells)
Signs and symptoms of the disease are not seen
Why does the body not attack its own tissues?
The body can recognise its own tissues as ‘self’
The body tolerates its own molecules - immunological tolerance
