Secondary non-specific and immune responses Flashcards Preview

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Flashcards in Secondary non-specific and immune responses Deck (32)
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1
Q

What are the two types of phagocytes?

A

Neutrophil and Macrophage.

2
Q

What are the features of a neutrophil?

A

Small, quick, die when finished.
Granular/thick cytoplasm.
Multi-lobed nucleus for squeezing through pores.

3
Q

What are the features of a macrophage?

A

Large, long lasting.
Release interleukin. (a cytokine)
Antigen-presenting cells.

4
Q

What is the mechanism by which macrophages present antigens?

A

Partially digested foreign body is combined with the MHC (Major Histocompatibility Complex) and presented on the cell surface membrane, activating the specific immune response.

5
Q

What is chemotaxis?

A

The movement of phagocytes towards chemicals produced by the pathogen/platelets/(cytokines).

6
Q

What is a phagosome?

A

The vesicle formed around a particle engulfed by a phagocyte via phagocytosis.

7
Q

What is a phagolysosome?

A

When a lysosome fuses with a phagosome, destroying the ingested pathogen.

8
Q

Outline the process of phagocytosis.

A

Chemotaxis, phagocytosis (pathogen engulfed) forming a phagosome, lysosome fuses forming a phagolysosome. The indigestible material is then discharged.

9
Q

What releases cytokines?

A

Phagocytes.
Mast cells.
T-helper cells.

10
Q

What do cytokines do?

What is an example of a cytokine?

A

Attract phagocytes, increase temperature, activates specific immune response.
Interleukin is an example of a cytokine.

11
Q

What do opsonins do?

A

Antibodies are opsonins.

Opsonins bind to antigens on antigen-presenting cells, making recognition by phagocytes easier.

12
Q

What is the first step of the immune response?

A

Pathogen engulfed by phagocytes and antigens presented on the surface of the macrophage.

13
Q

What does the presenting of antigens by macrophages cause?

A

Clonal selection of correct T-killer and T-helper cells.

14
Q

What is clonal selection?

A

Exposure to a specific antigen selectively stimulates the differentiation of cells with the appropriate antibody.

15
Q

What is clonal expansion?

A

Mass proliferation of lymphocytes by mitosis.

16
Q

What are the 2 types of lymphocytes?

A

B and T lymphocytes.

17
Q

Where are B-lymphocytes produced and where do they mature?

A

Both in the bone marrow.

18
Q

Where are T-lymphocytes produced and where do they mature?

A

Produced in the bone marrow, mature in the thymus gland.

19
Q

What response do B-lymphocytes produce?

A

Humoral response.

20
Q

What response to T-lymphocytes produce?

A

Cell mediated response.

21
Q

What are the different types of B-lymphocyte and what do they do?

A
Plasma cells (produce antibodies).
Memory cells (provide immunological memory).
22
Q

What are the different types of T-lymphocytes and what do they do?

A

T-killer cells (kill pathogens).
T-regulator cells (stop immune response when pathogen is dead, preventing auto-immune response).
T-memory cells.
T-helper cells (release interleukin and activate B-cells).

23
Q

How do T-killer cells destroy the pathogen?

A

They search for infected cells, attach to them and secrete toxic substances (hydrogen peroxide) into the cell, killing the pathogen.

24
Q

What happens after the B-lymphocytes are activated by interleukin released by the T-helper cells?

A

Clonal selection and clonal expansion of B-cells, causing them to differentiate into plasma cells and memory cells.

25
Q

What do B-cells require to be activated?

A

Interleukin and free antigens.

26
Q

What is an autoimmune disease?

A

When the immune system no longer recognises “self” cells and attacks them.
(an individual’s own body cells are antigenic)

27
Q

How are autoimmune diseases treated?

A

With immunosuppressants, however, this leaves the patient vulnerable to infection.

28
Q

What are some examples of autoimmune disease?

A

Lupus, rheumatoid arthritis, type one diabetes.

29
Q

What are antibodies?

A

Y-shaped glycoproteins. e.g: immunoglobulin

30
Q

What is the role of antibodies?

A

Agglutinins (agglutinate pathogens (clumping together)).
Anti-toxins (neutralising toxins on pathogens).
Prevent pathogens binding.
Opsonins (tag pathogens for phagocytosis (cause chemotaxis))

31
Q

What is the structure of an antibody?

A

Y-shaped structure with two heavy (long) polypeptide chains joined by disulphide bridges. Two light (short) polypeptide chains on either side. Antigen binding site (variable region) at the two tips of the Y.

32
Q

How do antibodies bind to antigens?

A

The antibody binding site is a variable region, with different specific shapes, complementary to different antigens.
The antigen binding site forms an antigen-antibody complex with the antigen.