12.1 - The immune system Flashcards Preview

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Flashcards in 12.1 - The immune system Deck (42):
1

What 2 types of defence mechanisms are there?

Non-specific responses
Specific responses

2

Give examples of non-specific responses

Barriers
Inflammation
Phagocytosis

3

Give examples of specific responses

Humoral response using antibodies
Cell-mediated response using T lymphocytes

4

List physical barriers

Skin
The conjunctiva
Ciliated epithelial lining
Stomach lining
Vagina lining

5

What is the outside of skin made of?

Keratin

6

What is keratin?

An insoluble protein

7

What is the role of the skin?

To prevent entry of pathogens

8

What is the conjunctiva?

Membrane covering the eye

9

What does the conjunctiva contain?

Enzymes (lysozyme)

10

What does the conjunctiva do?

Enzymes digest bacterial cell walls, destroying the bacteria

11

How do ciliated cells protect the body?

They waft mucus containing trapped pathogens out of the airways to the throat, where it is swallowed

12

How does the stomach lining protect us from pathogens?

Secretes HCl which destroys swallowed pathogens

13

How does the lining of the vagina protect us?

Acidic pH, reducing the ability of the bacteria to survive (enzymes don't function at acidic pH values

14

What is the inflammatory response?

A reaction which releases histamine, serotonin, and prostaglandins

Causes pain, swelling, redness

15

What effect does the release of histamine, serotonin, and prostaglandins have?

Dilate arterioles
Make walls of the capillaries more permeable
Increase blood flow to the area

16

Why does the inflammatory response make capillary walls more permeable?

Enables phagocytic cells to leave the blood more easily

17

Outline the stages of phagocytosis

1) Pathogens release chemicals
2) Damaged cells release cytokines which attract the phagocytes
3) Pathogen attaches to receptors on cell surface membrane of the phagocyte (directly/through opsonins)
4) Phagocytes surround the pathogen
5) Phagosome is formed
6) Lysosomes fuse with the phagosome
7) Hydrolytic enzymes digest and destroy the bacteria within the phagosome
8) Harmless products are released into the cytoplasm

18

What are phagocytes?

A specialised leucocyte that destroys bacteria by phagocytosis

19

Name phagocytic cells

Neutrophil
Monocyte

20

What are cytokines?

Cell signalling molecules used for communication between cells

21

What are opsonins?

Antibodies which bind to pathogens, making it more susceptible to phagocytosis

22

What is a phagosome?

A vacuole inside a phagocyte containing a foreign particle

23

What are monocytes?

White blood cells that differentiate to form macrophages

24

What are macrophages?

Phagocytic cells that release chemicals to attack bacterial cells, inhibit viral replication, and attract more macrophages

25

What triggers the specific immune response?

Antigens on the outer surfaces of organisms.
Non-self cells are targeted and destroyed.

26

What are the cells of the specific immune response?

T and B lymphocytes

27

Where are T and B lymphocytes produced?

Bone marrow

28

Where are T lymphocytes processed?

Thymus

29

Where are B lymphocytes processed?

Bone marrow

30

How are antigen presenting cells formed?

Dendritic cells engulf and digest pathogen and display its antigens on its cell surface membrane

31

What are dendritic cells?

Type of macrophage which becomes an antigen presenting cell

32

How are T cells formed?

T helper cell with complementary antigen to the dendritic cell is located.
The dendritic cell activates the T helper cell
T helper cells rapidly divide by mitosis, forming clones

33

What are types of T lymphocytes?

T helper cells
T regulatory cells
T killer cells

34

What do B cells have?

Receptors that are complementary to the pathogens antigens

35

What process do B cells use to divide?

Mitosis

36

What can B cells differentiate into?

Plasma cells
B memory cells

37

What do plasma cells do?

Synthesise and secrete antibodies with a complementary binding site to the pathogens antigens

38

What are T regulatory cells?

T cells that regulate the immune system, maintain tolerance to self-antigens, and prevent autoimmune disease.

39

What do T helper cells do?

Use cytokines to stimulate specific B lymphocyte production

40

How do B lymphocytes respond to a foreign antigen?

B cell with complementary receptors is stimulated to divide, forming a clone of plasma cells and a clone of memory cells. Plasma cells secrete antibodies into the circulation.

41

What will happen if a pathogen with the same antigens is encountered again?

Quicker antigen presentation
Quicker clonal selection and clonal expansion
Specific antibodies produced faster

42

What do T killer cells do?

Directly attack and destroy foreign cells