Non-specific Immune Response

Question 1

What makes up the immune system?

Answer 1

Consists of a collection of cells/molecules that work together to protect the body

Cells found in blood, organs and tissues around the body

Question 2

What are the 4 main functions of the immune system?

Answer 2

1) protect body against infection from microbes
2) destroy/neutralise non-living foreign matter eg dust
3) ‘immune surveillance’- destroy any abnormal cells appearing in the body
4) remove old/damaged cells from the body

Question 3

What are the 4 features of a good defence system?

Answer 3

1) provision of physical barriers, limiting invasion of the body by pathogens
2) ability to detect cells which are infected
3) ability to recognise infinite number of pathogens
4) distinguish between ‘self’ and ‘non-self’

Question 4

What is the specific immune system?

Answer 4

Recognises various antigens and will remember then again once it has been encountered

Question 5

What is the non-specific immune response?

Answer 5

More general reaction to infection and injury

Question 6

What are the features of a non-specific immune response?

Answer 6

Present at birth (innate)

No memory- elicits same response to every pathogen no matter how many previous encounters

Makes up the 1st and 2nd line of defence

Protects well against bacteria and viruses

Includes barriers, phagocytosis, inflammation, protective proteins and fever

Important cells- neutrophils, macrophages and natural killer cells

Question 7

What are the features of a specific immune response?

Answer 7

Built up over time

Memory- can remember specific pathogens so when encountered again bigger/faster stacks are made

Makes up the 3rd line of defence

Protects well against bacteria and fungi

Important cell- T and B lymphocytes

Includes- cell mediated immunity and humoral immunity

Question 8

What makes up the 1st line of defence?

Answer 8

Skin, mucous membranes, chemicals

Physical barriers

Question 9

What makes up the 2nd line of defence?

Answer 9

Phagocytosis, inflammatory process, protective proteins

Question 10

What makes up the 3rd line of defence?

Answer 10

Specific immunity (B and T cells), lymphocytes and antibodies

Question 11

What does phagocytosis mean?

Answer 11

Part of the non-specific response

Process by which cells of the immune system recognise, engulf and digest foreign cells and particles

Question 12

What is the process of phagocytosis?

Answer 12

1) macrophage/neutrophil attaches to the bacteria
2) macrophage flows around and engulfs the bacteria
3) vesicle is formed- Phagosome
4) lysosomes fuse with the phagosome- Phagolysosome
5) enzymes contained within the lysosomes are released destroying the bacteria
6) digested products are expelled from the cell or presented (antigen-presenting cells) to lymphocytes

Question 13

What is the function of Opsonins?

Answer 13

Coat foreign particle, making it easier for phagocytes to recognise and engulf it

Enhance phagocytosis

E.g. Antibodies

Question 14

What is the process of antigen presentation?

Answer 14

1) once phagocyte has digested the bacteria, displays breakdown products of bacteria on cell surface
2) products- epitopes
3) macrophage- Antigen presenting cell
4) antigen presented to helper T cell to initiate specific immune response

Question 15

What are the 4 main types of protective proteins?

Answer 15

Complement proteins, interferon, iron-binding proteins and anti-microbial proteins

Question 16

What is the function of complement proteins?

Answer 16

Some act as opsonins

Complement System- collection of proteins in blood, which can be activated in cascade reaction (e.g. clotting cascade)

Once activated they can:

1) destroy foreign cells- punches holes in cell membranes so fluid/electrolytes can flow into foreign cells, causing it to burst
2) enhance phagocytosis
3) chemotaxis- recruit other cells of immune system to site of infection
4) promote inflammation

Question 17

What is the function of interferons?

Answer 17

Group of proteins produced by lymphocytes/macrophages when infected by virus

Interfere with viral replication

Activate natural killer cells/macrophages

Question 18

What is the function of iron binding proteins?

Answer 18

Inhibit microbial growth- reduces amount of iron available to certain bacteria

Question 19

What are the functions of antimicrobial proteins?

Answer 19

Destroy a range of microorganisms

Attract other cells involved in inflammation e.g. Mast cells

Question 20

What are natural killer cells?

Answer 20

Type of lymphocyte

Destroy any abnormal cells in body

Cause altered cell to burst

Question 21

What is inflammation?

Answer 21

Tissue response preventing spread of infectious agents into nearby tissues

Involves: dilation of capillaries and increase in permeability, increase no. of WBC, phagocytosis to remove debris and cell division to replace injured cells

Clotting may also occur

Question 22

What are the effects of histamine released from mast cells?

Answer 22

1) increase blood flow to infected area- Bring WBC to area
2) increase capillary permeability- easier fro WBC/fluid to leave blood capillaries and enter infected area
3) more heat (body defences more active)
4) phagocytes activates- microorganisms engulfed
5) complement system/specific immune defences activated

Question 23

What are the symptoms/signs of inflammation?

Answer 23

Redness
Swelling
Heat
Pain