Immune System

Question 1

What is the immune system?

Answer 1

a collection of passive and active processes that protect us from the outside world and ourselves

Question 2

What is the role of the intrinsic system?

Answer 2

(barriers) prevent problems from happening

Question 3

What is the role of the innate system?

Answer 3

recognise non-self non-specifically

Question 4

What is the role of the adaptive system?

Answer 4

recognition of non-self specifically

Question 5

Where are immune cells made?

Answer 5

bone marrow and thymus

Question 6

What factors does the immune response depend on?

Answer 6

• having the right cell type in the right numbers to do the job neutropenia/ lymphopaenia
• can the cell travel to the infection site
• do the cells produce the appropriate molecules to kill/ restrict the pathogen

Question 7

What are the two mechanisms that the immune system uses to kill threats?

Answer 7

CONTACT DEPENDENT:
-immune cells encounter pathogens, engulf and destroy them
-immune cells communicate with each other to co-ordinate a response
SOLAUBLE FACTORS:
-the immune system produce soluble factors that kill pathogens directly
- the immune system produces molecules that regulate the immune response

Question 8

Give examples of biochemical barriers.

Answer 8

-lysosomes in tears
-nasal secretions
-saliva
sebaceous gland secretions
-commensal organsims in gut and vagina
-spermine in semen

Question 9

Give example of chemical and physical barriers

Answer 9

• mucus
• cilia lining trachea
• acid in stomach
• skin

Question 10

Why is disease not necessarily the most common outcome from infection?

Answer 10

because infections becoming disease depends on many factors

Question 11

What are the steps of progression of a typical infection?

Answer 11

1. establishment of infection
2. induction of adaptive response
3. adaptive immune response
4. immunological memory

Question 12

Describe the innate response.

Answer 12

• non-specific
• induced rapidly
• same speed of first and second encounter
• release cytokines
• phagocytose bacteria
• induce adaptive immunity

Question 13

Describe the adaptive response

Answer 13

• specific
• slow on first encounter
• faster on subsequent encounters
• vital for vaccine function

Question 14

What protects extracellularly?

Answer 14

antibodies

Question 15

What protects intracellularly?

Answer 15

T cells

Question 16

What is an antibody made up of?

Answer 16

• light chain
• heavy chain
• disulphide bonds

Question 17

What can antibodies target?

Answer 17

• bacterial toxins
• bacteria in extracellular space
• bacteria in plasma

Question 18

What happened when antibodies bind to bacteria?

Answer 18

1. neutralisation (prevent them from doing any damage)
2. marks them for being phagocytosed
3. if enough antibodies bind they can activate complement (a soluble protein in blood) and cause direct death of bacterial cell

Question 19

What is the role of vaccines?

Answer 19

to trick the body into making protective responses against pathogens without being infected

Question 20

Where and why is adaptive immunity tightly controlled?

Answer 20

• in sites like lymph nodes

- to avoid autoimmunity

Question 21

Where do T cells target?

Answer 21

inside cells

Question 22

Where do B cells and antibodies target?

Answer 22

outside cells