The Immune System Flashcards
What is an immune response
And what specific and non-specific response:
Body’s reaction to a foreign object
Specific response: -antigen specific and is aimed at specific pathogens.
Non specific response: happens in the same way for all organisms, whatever antigens
Main stages of the immune response
1) phagocytosis STEP:
They carry out NON SPECIFIC RESPONSE
1: the phagocyte recognises the antigens on a pathogen.
2: phagocyte engulfs the pathogen by phagocytosis, opsonise helps this.
3: pathogen is now contained in a phagosome ( a type of vesicles) in the cytoplasm of the phagocyte
4) lysosome fuses with phagosome, to break down the pathogen
5) APC’s: phagocyte then present the pathogens antigens on its surface, to activate other immune system cells. ANTIGEN PRESENTING CELLS.
Neutrophils- move towards wounds in response to cytokines, released by cells at the sites of a wound
Main stages of the immune response
2nd step of immune response:
T-Lymphocyte activation:
- A T-Lymphocyte- type of white blood cell
- receptors bind to antigens presented by APC’s
- each T lymphocyte has different receptors on its surface
- receptor of a t-lymphocyte binds to complimentary antigens on pathogens
CLONAL SELECTION IS ACTIVATING T-LYMPHOCYTES
CLONAL EXPANSION IS WHEN THE ACTIVATED T-LYMPHOCYTES DIVIDE
Different types of T Cells
3 types
1) T helper cells- release substances that activate B-lymphocytes and T killer cells
2) T-killer cells: Attach to and kill cells that are infected with a virus.
3) T regulatory cells: suppress the immune response from other white blood cells. Helps to stop immune system cells from accidentally attacking the host cells
Main stages of the immune response
3rd STEP: B lymphocyte activation and plasma cell production
B lymphocyte: covered with antibodies.
Proteins bind to antigens to form an ANTIGEN- ANTIBODY COMPLEX
Different B lymphocytes bind to different shapes antigens
HAS TO BE COMPLEMENTARY.
Main stages of the immune response
4th STEP: ANTIBODY PRODUCT
- Plasma cells are clones of the B lymphocyte
- secrete loads of antibody specific to the antigen into the blood.
- this is the signals for the immune system to attack and destroy the pathogen.
What is cell signalling
How cells communicate
- cell releases a substance that binds to a receptor of the cell
- cell signalling helps activate all the different types of white blood cells that are needed.
T helper
CELL SIGNALLING
- T helper cells release interleukins
- That bind to RECEPTORS on B- lymphocytes
- activating the B lymphocytes
Neutrophil, lymphocyte, monocyte
BLOOD SMEARS
Neutrophil- 3 interconnected blobs, grainy cytoplasm
Lymphocyte- much smaller than the neutrophil
NUCLEUS takes up most of the Lymphocyte (very little cytoplasm)
Monocyte- Biggest white blood cell
Non-grainy cytoplasm
