Immune System Flashcards
(28 cards)
what is the main purpose of the immune system.
To destroy any pathogens that enter our body.
what is the first line of defense
our bodies natural barriers - they stop pathogens infecting our body in the first place.
list the bodies natural barriers - give me 6
- the skin
- blood clotting
- inflammation
- ciliated mucous membranes
- lysozomes
- phagocytosis
describe how the skin acts as the bodies fist line of defense from pathogens.
the skin has an outer layer of dry, dead hardened cells filled with keratin.
- a physical barrier to pathogens.
how does blood clot to defend the body from pathogens at wounds.
thrombocytes collect together, which release clotting factors to form a fibrin plug.
- this seals the wounds.
describe what happens at a site of inflammation
the area around the wound swells and becomes warm and painful to touch.
- this process localises breaks in the barrier.
what is the purpose of the ciliated mucous membranes
the mucous contains glycoproteins that make it sticky, it traps the microbes in inhaled air.
- the cilia then waft the trapped particles to the back of the thoat to be swallowed.
what are lysozymes, where are they found and whats their role in defense.
they are antibacterial enzymes - found in tears, saliva and stomach acid.
they break down the cell wall of bacteria.
what is phagocytosis and what is its role in defense
phagocytosis is a non-specific immune defense process.
- phagocytes ingest (by endocytosis) pathogens or infected cells and digest them with enzymes.
what are antigens, and where are they found.
- they are any substance found on the surface of pathogens.
- when introduced in the blood or tissue, it induces the production of antibodies.
what are antibodies, and what process are they produced in?
they are proteins produced by lymphocytes when in the presence of a specific antigen.
- this is the specific immune response.
what are the bodies 2 immunity systems
- humoral repsonse
- cell mediated response.
in the humoral response, what cells are responsible for detecting a specific antigen. and what is stimulted after detection.
B lymphocytes detect the specific antigen and this stimulates the production of plasma cells and memory cells.
what cells are responsible for producing antibodies
plasma cells. each antibody is specific to an antigen.
in the humoral response, what do the antibodies do
they bind with the antigen to form an antigen-antibody complex. this inactivates the antigen which increases the rate of ingestion by phagocytosis.
in the cell mediated response, when a specific antigen is detected, what cels are produced.
T Lymphocytes.
list the sub-populations of T-Cells
- Effector cells
- Helper T cells
- Memory cells
what is the purpose of the effector T cells.
- cause lysis of target cells, they include the T killer cells and cytotoxic T lymphocytes.
what is the purpose of the T helper cells
they co-operate with B-lymphocytes to intiate an antibody repsonse.
what is the purpose of T memory cells
they stay dormant until the person is next exposed to the same antigen.
list the cell mediated defences
- activation of phagocytes
- activation of antigen specific response: T killer cells and cytotoxic T lymphocytes.
what happens when B lymphocytes are active
they relese cytokines in response to an antigen.
- which promotes effector and memory cell responses.
what is the primary immune response
it occurs when a person encounters an antigen for the first time.
why is there a considerable time delay after antigen encountered.
becuase it takes time to clone and differentiate specific T and B cells.
and synthesise antibodies.
- this delay is why symptoms are often experiened.
- memory cells are produced here.
