Immunity system Flashcards
Immunity is protection…
against disease provided by the immune system.
External defence system:
- epithelia in airways
- hydrochloric acid in the stomach
- blood clotting
Internal defence system consists of…
the white blood cells.
An immune response is…
the response of lymphocytes to the presence of a foreign antigen.
Phagocytes are produced in…
the bone marrow and are stored there.
Phagocytes act as scavengers, so…
they remove dead cells and invasive foreign microorganisms.
Two types of phagocytes:
Macrophages and neutrophils
Neutrophils travel around…
the body and patrol the tissues. They can squeeze through the walls of capillaries.
Neutrophils are released in…
large numbers form their stores. They are short-lived cells.
Neutrophil’s nucleus is…
granular.
Macrophages are larger than…
neutrophils.
Macrophages are found in…
organs(lymph, nodes, lungs)
Macrophages are made in…
bone marrow, travel as monocytes and develop in macrophages.
Macrophages are long…
lived cells.
Macrophages initiate the immune…
response by cutting the pathogen to display antigens that are recognised by lymphocytes.
Every pathogen releases…
histamine which attracts neutrophils.
Antigens on the surface of the pathogen stimulate…
the neutrophils to attack as the receptor proteins on the surface of the neutrophils recognise the antigen molecule.
A pathogen is engulfed by…
neutrophil in the process of endocytosis.
Lysosome containing…
digestive enzymes fuses with vacuole containing pathogen inside the cell.
When neutrophil dies…
pus is formed.
Neutrophil can destroy more than one…
pathogen.
The pathogens can be recognised due to…
proteins, glycoproteins, lipids, polysaccharides and the waste materials produced by the pathogen.
An antigen is any molecule…
which the body recognises as foreign.
Antibodies are…
glycoproteins that act against specific antigens.
Chemotaxis is the movement of…
neutrophils towards a chemical stimulus.
Lymphocytes have a large…
nucleus that fills most of the cell.
B-lymphocytes remain in…
the bone marrow until they are mature and then spread throughout the body, concentrating in lymph nodes and the spleen.
T-lymphocytes leave…
the bone marrow and collect in the thymus where they mature.
The thymus is a gland that…
lies in the chest just beneath the sternum.
During the maturation process many different…
types of B and T lymphocytes are produced. Each type is specialised to respond to one antigen.
B and T cells circulate…
between the blood and lymph. This ensures that they are distributed throughout the whole body.
Immune responses depend on…
B and T cells interacting with each other.
As the B cell matures it gains…
ability to make just only one type of antibody molecule.
As the B cells are maturing…
the genes that code for antibodies change in many ways to code for different antibodies.
A clone is…
small group of identical cells.
Clonal selection is…
when a small number of B cells with complementary receptors to foreign antigen divide by mitosis.
Some of the activated B cells become…
plasma cells and some memory cells.
Plasma cells produce…
antibodies very quickly.
Plasma cells do not…
live very long. After a week their number rapidly decreases.
Antibodies stay in the blood longer than…
plasma cells but their concentration decrease as well over time.
Memory cells remain circulating…
in the body for a long time.
If the antigen enters the body a second time…
memory cells divide rapidly and develop into plasma cells and more memory cells. Therefore, infection is removed before any symptoms or signs can develop.
The primary response is…
slow because at this stage there are few B cells that are specific for the antigen.
The secondary response is…
faster as there are many memory cells, which can quickly divide.
Immunological memory is…
the ability of the immune system to quickly respond to foreign antigen after it enters the body again.
