3.2.4 Cell Recognition Flashcards
What is a Pathogen
a disease causing microorganism
What are Antigens?
-proteins on the surface if a cell that is recognized as non-self by immune system and stimulate an immune response
Where are antigens found?
-Pathogens
-cells from other organisms
-abnormal body cells (tumors)
toxins from bacteria
What are Phagocytes?
type of white blood cells that are attracted by chemicals released by pathogens (or dead/damaged cells)
NON SPECIFIC
How does phagocytosis work?
1) ENDOCYTOSES, pathogen engulfed
2) PHAGOSOME FORMATION, vesicle
3) PHAGOSOME-LYSOSOME MERGE
4) break bacterial wall and reuse useful products
5) DEBRIS DIGESTION+ANTIGEN PRESENTATION
the 2 types of Lymphocytes and where they mature
both produced by stem cells in bone marrow
-B CELLS mature in marrow
T CELLS mature in Thymus Gland
T-Lymphocytes
mediated response
- have receptors which respond to antigens
- Helper T-Cells clones itself once attached to antigen
What do Helper T Cells do?
- develop into memory T Cells
- stimulate phagocytosis
- activate B Cells
- causes Tc to kill infected cells
How do Cytotoxic T Cells kill bacteria?
- release chemical cytokines (e.g. perforin which makes holes in cell membrane of bacteria)
B-Lymphocytes (+how they clone)
humeral response
produce antibodies which cause AGGLUTINATION and act as MARKER for lymphocytes
-b cells take in antigens by endocytosis and present them on surface, once T-helper cells bind to them, b cells form clone CLONAL SELECTION
Antibody structure
2 heavy chains and 2 short chains
constant region binds to B-cell, variable region is SPECIFIC+COMPLIMENTARY to antigen of foreign cell
forms antigen-antibody complex when binds