Unit 3: Neurobiology and immunology - Specific Cellular Defences Against Pathogens Flashcards
What is specific immune response brought about by?
White blood cells called lymphocytes.
Where are lymphocytes produced?
From stem cells in bone marrow.
What are two types of lymphocytes?
B and T lymphocytes.
What do lymphocytes respond to?
Specific antigens on invading pathogens.
What is an antigen?
A molecule (often a protein) found on the surface of cells.
What are two types of antigens?
Self antigens (belong to the body’s own cells) and foreign antigens (do not belong to the body’s own cells).
What do foreign antigens do?
Trigger a specific immune response.
What do lymphocytes have in terms of antigens?
Lymphocytes have a single type of antigen receptor which is specific for one antigen.
After foreign antigen binding what does the lymphocyte do?
The lymphocyte divides repeatedly, resulting in the formation of a clonal population of identical lymphocytes.
What do B lymphocytes do?
B lymphocytes produce antibodies against antigens and this leads to destruction of a pathogen.
What are antibodies?
Antibodies are Y-shaped proteins with receptor binding sites that are specific to a particular antigen on a pathogen.
Why does an allergic reaction happen?
When B lymphocytes respond to antigens on substances that are harmless to the body e.g. pollen. This hypersensitive response is called an allergic reaction.
Which type of lymphocytes produce antibodies?
B lymphocytes.
What do T lymphocytes do?
T lymphocytes destroy infected body cells by recognising antigens on the pathogen on the cell surface.
How do T lymphocytes destroy infected body cells?
They attach onto the infected cells and release proteins. These proteins diffuse into the infected cells causing the production of self-destructive enzymes which cause cell death.
