IMMUNE RESPONSE

Question 1

two types of immune system (2)

Answer 1

• innate immune system, natural barriers to resist infection

- adaptive immune system, produces a specific response to each antigen

Question 2

how does the skin protect? (3)

Answer 2

• innate immune system
• keratin in epidermal cells makes skin waterproof
• collagen in connective tissue makes skin strong

Question 3

what happens if the skin is breached? (3)

Answer 3

• when capillaries are broken blood clots prevent microbes entering
• inflammation causes increased bloodflow to site, including phagocytic cells
• broken capillaries heal and bring temperature up to hurt microbes

Question 4

skin flora/microbiota (2)

Answer 4

• layer of bactria/fungi that outcompete pathogenic strains

- protected against by regular washing

Question 5

inhaled air (3)

Answer 5

• contains microbes/spores
• trapped by mucus
• epithelial cells’ cilla lining respiratory pathways move them to the oesophagus to be swallowed

Question 6

microbes in blood stream

Answer 6

• phagocytic cells - macrophages, neutrophils engulf and digest them

Question 7

tears, mucus saliva

Answer 7

• contain lysozyme that hydrolyse peptidoglycan in bacteria ell walls

Question 8

stomach acid

Answer 8

• kills many ingested microbes

Question 9

adaptive immune system (4)

Answer 9

• adapting by providing a specific response to each antigen
• done by lymphocytes
• derived by stem cells in the bone marrow
• role depends on location

Question 10

two parts of adaptive response (2)

Answer 10

• humoral response

- cell-mediated response

Question 11

humoral response (5)

Answer 11

• production of antibodies
• B lymphocytes mature in spleen/lymph nodes
• receptors respond to foreign proteins and they divide into…
• plasma cells that release antibodies
• memory cells which remain dormant until the same antigen is encountered, then they divide into b lymphocytes again

Question 12

cell-mediated response (6)

Answer 12

• activation of phagocytic cells
• t- lymphocytes activated in thymus gland and they divide into…
• t memory cells that remain dormant until they encounter the same antigen and divide to form more t lymphocytes
• t killer/ cytotoxic t cells that kill antigens by lysing them
• to helper cells that release chemicals, including cytokines
• cytokines stimulate phagocytic cells (marcophages, monocytes, neutrophils) to engulf pathogens

Question 13

clonal expansion (3)

Answer 13

• B & T lymphocytes divide repeatedly into genetically identical cells forming a large population specific to an antigen
• these cells then differentiate into various lymphocytes
• B lymphocytes divide to make antibodies

Question 14

primary immune response (4)

Answer 14

• antigen presentation occurs
• t helper cells detect antigens by secreting cytokines
• b plasma cells secrete antibodies for 3 weeks-
• symptoms subside

Question 15

antigen presentation

Answer 15

• where macrophages engulf foreign antigen and incorporate antigenic molecules into cell membrane

Question 16

secondary immune response (3)

Answer 16

• relies on memory cells to protect against reinfection
• antibodies are made more quickly, and are more concentrated
• remain at high concentration in circulation for longer and no symptoms occur

Question 17

active immunity (2)

Answer 17

• body makes own antibodies, stimulated by infection or vaccination
• long lasting because response produces memory cell

Question 18

how does vaccination affect the immune system

Answer 18

• triggers cell-mediated and humoral response

Question 19

vaccines can be… (4)

Answer 19

• antigens isolated from pathogen
• weakened strains of the pathogen
• inactive/killed pathogen
• inactivated toxin

Question 20

booster (2)

Answer 20

• over time memory cells decrease if not exposed again

- boosters re-expose so faster, bigger & longer-lasting response

Question 21

passive immunity

Answer 21

• receive antibodies produced by another

Question 22

sources of passive immunity (3)

Answer 22

• mother to foetus across placenta
• to baby via breast milk
• antibody injections

Question 23

antibody injections used… (2)

Answer 23

• when there’s no time for active i.e being bitten by a rabid animal
• PIDD (primary immune deficiency disease)/ HIV/aids where patient doesn’t make enough antibodies

Question 24

how long do antibody injections last? (2)

Answer 24

• not long bc. body begins to attack it as it is foreign

- no memory cells formed

Question 25

for a vaccination to be successful… (2)

Answer 25

• antigen must be immunogenic (one dose causing a strong response
• one antigenic type so only one vaccine is needed to stop all strains

Question 26

people unsuitable for vaccination (5)

Answer 26

• immunocompromised
• taking chemotherapy
• living with HIV/AIDS
• very old
• very ill

Question 27

reasons not to have vaccines (5)

Answer 27

• medical reasons
• religious objections
• preference for natural/alternative medicine
• mistrust of pharmaceutical companies
• safety fears

Question 28

factors considered when offering vaccination programs (4)

Answer 28

• cost vs effectiveness
• protection of individual vs protection of community
• rights of individual with mandatory/voluntary programmes
• side effects, whether real/percieved