2.8: The Adaptive Immune System Flashcards
1
Q
Antibodies vs Antigens
A
- An antigen is a substance that triggers the body to an immune response. Can be proteins within or outside the body that causes the body to create a defense against the pathogen.
- Antibodies are proteins that recognise and bind to antigens within the body. They are Y-shaped proteins produced by B Cells, when antigens are detected. Antibodies circulate in your body once created to identify, attack, and destroy the same type of antigens if they enter the body again.
2
Q
Adaptive Immune System
A
Third line of defence. Adaptive or acquired immune response to pathogens, it involves a specific response, where the body retains a memory of pathogens through antibodies and proteins. Involves lymphocytes: b cells and t cells
3
Q
What makes up the adaptive immune system
A
- The lymphatic system: a network of vessels found near blood capillaries. Lymph nodes contain white blood cells of both the innate and adaptive immune system
- Organs of the immune system: primary and secondary
- Primary organs: Include bone marrow and thymus glland where lymphocytes are developed
- Secondary organs: Lymph nodes, spleen, tonsils. These organs recognise pathogens and mount their response
4
Q
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5
Q
Major Histo-compatability Complex (MHC)
A
- Set of protein markers on the surface of cells
- There are two groups of marker proteins:
1. ‘Self’ proteins are unique to each individual
2. Section sof protein antigens from pathogens are recognised as ‘Non-self’ proteins
6
Q
Lymphocytes
A
- Type of white Blood cell that originates from bone marrow
- these cells are responsible for antibody production and regulation of the immune response.
- Two groups: B lymphocytes (cells): mature in bone marrow; T lymphocytes (Cells) mature in the thymus gland
7
Q
B Lymphocytes
A
- B Lymphocytes are white blood cells that originate and mature in bone marrow
- At birth, you have a variety of these cells, with different receptors to detect different antigens
- When B Lymphocytes encounter an antigen, they divide to make Plasma Cells and Memory cells
- Plasma B cells release antibodies to remove antigens
- Memory B cells will quick remove antigens if they return to the body
- The presence of B Lymphocytes is largely responsible for the quick immune response. Most people do not even display smptoms of illness during a secondary immune response.
8
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9
Q
T Lymphocytes
A
- T cells do not use antibodies as the mode of action
- There are 3 types of T cells indentified based on role:
1. Killer T cells: known as cytotoxic: these cells identify infected cells and release chemicals to destroy them
2. Helper T cells: When activiated, Helper T cells increase the number of cells that respond to the specific antigen, increase the number of Killer cells, memory T cells, and B cells
3. Memory T cells: Similar to memory B cells, T cells have specific surface receptors, keeping a memory of antigens after the initial infection. Therefore the body initiates a quicker, larger response when infected a second time by pathogen.
10
Q
Adaptive immunity
A
- Third line of defence
- Adaptive immune responses may not be as fast or significant enough to prevent a person from getting sick
- Because there is an enhanced the response to the secondary pathogen exposure, it is important to ensure the individual has been pre-exposed to the pathogen
- There are two types of adaptive immunity:
1. Active
2. Passive
11
Q
Active Immunity
A
- Involves activating an immune response in the body
- Promotes a person’s body to produce memory cells, stored in spleen and lymph nodes to kill antigens
- Can be achieved by either: exposure to pathogen and antigen or exposure to a vaccine whicich is a harmless version of an antigen
12
Q
Passive Immunity
A
- Antibodies are provided to temporarily protect individuals
- For example: placenta during pregnancy, receives mothers antibodies through breast milk in the early stages of life, when a person receives an injection of antibodies to protect against the effects of a toxin such as snake venom.
