2C - Cells And The Immune System Flashcards
What are antigens?
Proteins on the surface of cells that can generate an immune response when detected by the body.
What can antigens allow the body to recognise?
- Pathogens
- Abnormal body cells
- Toxins
- Cells from other individuals of the same species
What are pathogens?
Organisms that cause disease.
What is the difference between T-cells and T-lymphocytes?
Nothing, they are the same thing (a type of white blood cell).
Are specific lymphocytes produced in response to an infection?
- No, they all already exist.
- There are many different types -> Only a few will match the pathogen’s antigens.
- The ones that match are stimulated to divide -> Clonal selection.
What are the types of defence mechanism against infection?
- Non-specific -> Physical barrier + Phagocytosis
* Specific -> Cell-mediated response + Humoral response
What is the difference between the non-specific and specific immune response?
- Non-specific -> Immediate and the same for all pathogens
* Specific -> Slower and specific to each pathogen
What are the different types of white blood cell?
- Phagocytes
* Lymphocytes -> T-cell + B-cell
What are phagocytes?
A type of white blood cell that ingest and destroy pathogens (phagocytosis).
What are lymphocytes?
White blood cells involved in the specific immune response.
What is phagocytosis?
The process by which phagocytes engulf and digest pathogens.
Describe the process of phagocytosis.
1) Phagocyte is attracted to the pathogen by its chemical products + moves along the concentration gradient towards it.
2) Phagocyte attaches onto the pathogen’s antigens.
3) Cytoplasm moves around the pathogen + forms a phagosome.
4) Lysosomes in the phagocyte migrate towards the phagosome and release lysozymes into it.
5) Lysosomes hydrolyse the pathogen + the products are absorbed by the phagocyte.
6) Phagocyte displays antigens on the cell surface to activate other cells.
What is a phagosome?
The “bubble” that is formed around the pathogen when a phagosome engulfs it.
What are lysosomes and lysozymes?
- Lysosomes -> Sacs that contain lysozymes.
* Lysozymes -> Enzymes that break down (hydrolyse) forgein material.
Compare how quickly non-specific and specific immune response happens.
Non-specific is faster, but specific provides long-term immunity.
What is another name for B lymphocytes?
B cells
What is another name for T lymphocytes?
T cells
Are phagocytes and lymphocytes part of the specific or non-specific immune response?
- Phagocytes -> Non-specific
* Lymphocytes -> Specific
Where are lymphocytes produced?
By stem cells in the bone marrow.
What is the cellular immune response?
The T-cells and other immune system cells that they interact with -> e.g. Phagocytes
What is the humoral immune response?
B-cells, clonal selection and the production of monoclonal antibodies.
What type of cells is the cellular immune response associated with?
T-cells
What type of cells is the humoral immune response associated with?
B-cells
What are the two parts of immune response?
- Cellular
* Humoral