5.1 and 5.2: phagocytosis Flashcards
Inducing the immune response
4
cells from other organisms
abnormal body cells
pathogens
toxins
Immune response:
Cells from other organisms
Immune cells detect the presence of other cells from different organisms of the small species
eg: organ transplant
Immune response:
Abnormal body cells
Immune cells can detect the presence of body cells that aren’t functioning as normal
eg: cancerous cells
Immune response:
Pathogens
Immune cells can detect the presence of pathogens
- micro-organisms (bacteria and viruses)
- fungi and protists
Immune response:
Toxins
Immune cells can detect the presence of toxins which are harmful substances produced by pathogens
Antigens
Molecules that occur on the cell surface membrane of all cells which signal the immune system if cells are foreign
-either glycoproteins or proteins
Specific antigens
Every cell has specific antigens which bind to complementary receptors on the cell surface membrane of immune cells
(if antigens foreign = immune response)
Self signals
antigens signal if they cells are self or the host organisms
Phagocytosis
Phagocytes are white blood cells which ingest pathogens then form a phagosome (vesicle.) Then lysosomes fuse with the vesicle and lysozome enzymes hydrolyse the bacteria and the products and absorbed into the cytoplasm
T lymphocyte cells activated
Phagocytes activate t cells
-cytoxic t cells
-t helper cells
cellular response
B lymphocyte cells activated
t cells activate b cells
b cells divide into plasma cells (mitosis)
humoral response
Production of antibodies
Plasma cells secrete antibodies
Antibodies
Proteins that bind to specific antigens on the cell surface membrane of pathogens
Apoptosis
Programmed cell death.
for lymphocytes that show an immune response to self antigens
Immediate defence mechanism
2
Barrier of entry (skin)
Phagocytosis
