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Flashcards in The adaptive immune system Deck (22)
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1
Q

What does the adaptive immune system rely on?

A

Recognition of antigens.

2
Q

What is the name of receptors on lymphocytes that can recognise foreign antigens?

A

The lymphocyte repertoire.

3
Q

What causes the diversity of recognition receptors and antibodies?

A

Gene recombination.

4
Q

What is the TCR?

A

The T cell receptor on the surface of T cells that is responsible for recognizing fragments of antigen.

5
Q

What are they key cells in the adaptive immune system?

A

B cells, T helper cells and T cytotoxic cells.

6
Q

What is the difference between humoural immunity and cell mediated immunity?

A

Humoural - antibodies produced, cell mediated - T cells induce apoptosis of the infected cells.

7
Q

Where are B cells derived from?

A

Bone marrow - and mature here.

8
Q

Where are T cells derived from?

A

The thymus.

9
Q

What are Treg cells?

A

T regulatory cells.

10
Q

What are the characteristics of lymphocytes?

A

They are small, round cells that have a high nucleus to cytoplasm ratio. They are a type of mature B cells.

11
Q

What are antigen presenting cells?

A

Specialised cells that capture microbes and another foreign antigens, and present them to lymphocytes in conjunction with other costimulatory signals.

12
Q

What are the main antigen presenting cells?

A

Dendritic cells in epithelia and most organs.

13
Q

What do dendritic cells do to antigens?

A

Take up antigen, process it and carry it to T cells in lymph nodes.

14
Q

What other types of cells can act as antigen presenting cells?

A

Macrophages and B cells.

15
Q

Where do lymphocytes originate?

A

In the bone marrow, derived from haemopoietic stem cells.

16
Q

What happens to T cells in the thymus?

A

They mature and undergo selection - primary lymphoid organs - where they are formed and mature.

17
Q

What happens to mature T cells?

A

They leave primary lymphoid organs and enter circulation to reach lymph nodes - secondary lymphoid organs.

18
Q

What happens to antigens entering through epithelia?

A

They are carried in the lymphatics to nodes.

19
Q

What happens to antigens that are blood bourne?

A

They enter the spleen.

20
Q

What response do T cells cause?

A

Cell mediated cytotoxicity, activation of macrophages and recruitment of neutrophils.

21
Q

What response do B cells cause?

A

Antibody production - phagocytosis.

22
Q

What is homeostasis?

A

The return to resting state after elimination of antigen. It involves the apoptosis of excess cells.