Response To Infection topic 6

Question 1

Physical barriers

Answer 1

• lysozyme in tears
• skin surface (flora)
• digestive system (gut flora)
• mucus lining trachea

Question 2

Non specific responses

Answer 2

• inflammation
• phagocytosis
• interferons
• lysozyme

Question 3

Specific responses

Answer 3

T cells
B cells
(Lymphocytes)

Question 4

WHITE BLOOD CELLS- Lymphocyte

Answer 4

Involved in specific immune response

• type of leukocyte
• in blood and lymph nodes
• recognise antigen molecules on surface of pathogen and co ordinate response
• large nucleus

Question 5

WHITE BLOOD CELLS- neutrophil

Answer 5

Lobed nucleus- diapedesis
Phagocytosis: 
1. Migration and diapedesis
2. Opsonisation (tagging as foreign) and recognition
3. Ingestion

Question 6

WHITE BLOOD CELLS- Macrophage

Answer 6

Phagocytosis

• activation of lymphocytes
• tumour killing
• fever and inflammation
• tissue repair by collagenase
• arrives at infection later than neutrophils as live longer
• involved in antigen presentation

Question 7

WHITE BLOOD CELLS- monocytes

Answer 7

Become macrophages

Question 8

WHITE BLOOD CELLS- basophils

Answer 8

Produce histamine- allergic response

Question 9

WHITE BLOOD CELLS- Eosinophil

Answer 9

Allergic response or in response to parasites

Question 10

Process of inflammation

Answer 10

1. Pathogens enter damaged tissue. Damaged cells release chemical substances that act as inflammatory mediators- histamine.
2. Chemicals cause increase in blood flow and permeability of capillary. =Flooded with fluid and blood clotting elements causing swelling and redness.
3. Tissue cells release chemicals that attract phagocytic white blood cells such as neutrophils and macrophages.
4. Phagocytosis begins when wbc recognises pathogen as foreign
5. The cell membrane of the macrophage fuses around bacterium trapping it inside a phagosome.
6. Phagosome fuses with a lysozyme= phagolysosome. Bacterium is broken down and digested
7. Macrophage absorbs useful material and expels the rest
8. Anti inflammatory factors reduce swilling and skin heals

Question 11

What are the 2 main specific responses?

Answer 11

Cell mediated- targets pathogens inside cells

Humoral- target pathogens in body fluid with antibodies

Question 12

Cell mediated specific response process

Answer 12

1. When a macrophage destroys the pathogen it displays the pathogens antigen on it’s cell-surface out of the MHC that signals it is part of the body. It is an antigen presenting cell.
2. Release of interleukin 1 attracts T helper cells. One T helper will be complimentary to the displayed antigen and bind.
3. T-helper cell will release interleukin 2 stimulating the growth and development antigen-specific T killer cells. It will make copies of itself.
4. T killer cells detect the antigen on infected body cells and produce perforin which target the cell membrane allowing water in which causes cell lysis.
5. Some of the cells developed will be T memory cells in case the body is infected again.

Question 13

Humoral immune response process

Answer 13

1. When a macrophage destroys the pathogen it displays the pathogens antigen on it’s cell-surface out of the MHC that signals it is part of the body. It is an antigen presenting cell.
2. Release of interleukin 1 attracts T helper cells. One T helper will be complimentary to the displayed antigen and bind.
3. T-helper cell releases interleukin 2 stimulating effector B cells to become plasma cells
4. Plasma cells divide and produce antigen-specific antibodies which are released and attach to pathogens
5. Some of the B effector cells develop into B memory cells instead of plasma

Question 14

How is fever produced

Answer 14

Pyrogens

When a pathogen infects the body the hypothalamus rests the temp to higher than 37

Question 15

Advantages of fever

Answer 15

Pathogens reproduce better below this

Specific immune response works better higher temperature

Question 16

Body temperature following bacterial infection

Answer 16

Temperature rises steadily and remains high until infection ceases

Question 17

Body temperature following viral infection

Answer 17

Temperature spikes shooting high every time viruses lyse cells

Question 18

How antibodies inactivate pathogens- neutralisation

Answer 18

They bind to antigens and prevent pathogens from attaching to and entering host cells. This encourages macrophages to destroy the pathogen.

Question 19

How antibodies inactivate pathogens-agglutination

Answer 19

They bind to antigens on many pathogens clumping them together so they are too big to enter cell. Macrophages can recognise and destroy them.

Question 20

Types of adaptive immunity

Answer 20

Natural-active (infection) passive (maternal)

Artificial-active (vaccination) passive (Ab transfer)

Question 21

What is herd immunity

Answer 21

Indirect protection from infectious disease that occurs when a large percentage of the population are immune so the chains of infection are destroyed

Question 22

When do you need to increase the percentage of immunity for herd immunity

Answer 22

It’s a pathogen has a higher reproduction number which is how many people one infected person will infect

Question 23

Why is the MMR vaccine more effective than single vaccinations

Answer 23

The uptake was increased if people got them done all at once

Question 24

Pros of the MMR vaccination

Answer 24

One. Individual protection from harm and death.
Two. Benefit to society-herd immunity
Three. Reduction on treatment cost as less cases are developed.

Question 25

Cons of the MMR vaccination

Answer 25

One. Allergy to eggs.
Two. Reaction to the vaccination some brain damaged/ died in early development.
Three. Link to rise and asthma and allergies?
Four. vaccinating for the benefit of society over individuals.