Immunity

Question 1

Vaccination

Answer 1

• Weakened/dead or products of a pathogen in a vaccine
• Usually introduced into body by injection
• Bodies immune system responds
• Antibodies produced to deal with perceived threat
• Person does not get ill since no actual pathogen is present
• Immunity acquired (memory of particular pathogen)
• Often booster vaccines required for life long immunity
• When the actual pathogen enters body, immune response initiated
• Response much quicker due to memory from vaccine
• Person does not suffer disease due to immunity

Question 2

Lymph node

Answer 2

• Small mass of tissue that filters lymph
• Holds lymphocytes

Question 3

Pandemic

Answer 3

• An epidemic of infectious disease that has spread through human populations across a large region;
• for instance multiple continents, or even worldwide

Question 4

Passive immunity

Answer 4

• Preformed antibodies found in the blood
• providing short term immunity
• Naturally acquired for babies through placenta and breast milk
• Artificially acquired by injection of specific antibodies

Question 5

Naturally acquired active immunity

Answer 5

• Person exposed to pathogen
• Immune system develops a response to a particular antigen
• Person recovers
• A memory is retained for that particular pathogen
• This allows a rapid response when re-exposed
• The person is now immune to this pathogen

Question 6

Causes of inflammation

Answer 6

• Mast cells produce histamines when damaged
• Blood vessels dilate increasing blood flow
• Extra tissue fluid forced into area
• phagocytic cells accumulate to clean up

Question 7

Phagocytic cell example and role

Answer 7

• Macrophages,
• engulf pathogens and foreign matter

Question 8

Cells responsible for specific immunity

Answer 8

White blood cells:

• B-lymphocytes
• T-lymphocytes

Question 9

Primary immune response

Answer 9

• Lag in response
• Antibodies slowly manufactured
• Pathogen able to increase numbers
• Individual suffers from disease

Question 10

Spleen

Answer 10

• Organ that identifies and responds to foreign matter in blood
• filters and destroys bacteria and worn out red blood cells
• blood reservoir

Question 11

Tonsils

Answer 11

• Large group of lymph nodes
• Protects mouth and nose from bacteria and foreign substances

Question 12

Epidemic

Answer 12

a widespread occurrence of an infectious disease in a community at a particular time.

Question 13

Lymph

Answer 13

• Lymph fluid forms from excess tissue fluid
• Lymph drains into subclavian veins (bloodstream) becoming blood plasma

Question 14

Antigen

Answer 14

• A protein in cell membranes that causes a specific immune response
• Different cells have different antigens specific to them

Question 15

Cell mediated immune response

Answer 15

• T-lymphocytes attach to antigens on pathogen or infected cells
• They kill or destroy foreign cells

Question 16

Non-specific defences

Answer 16

• Barriers (e.g. Skin, mucous)
• Specialised cells (e.g. Phagocytes)
• Chemicals (e.g. Histamine)
• Genetic barriers (e.g. Host specific diseases)

Question 17

Thymus gland

Answer 17

• Found near the heart
• T-lymphocytes mature and specialise here

Question 18

The two levels of the bodies’ defence system against pathogens

Answer 18

• Non-specific (innate) immunity
• Specific immunity

Question 19

Artificially acquired active immunity

Answer 19

• Vaccination
• person exposure to a pathogens antigens (dead/weakened pathogen)
• immune system responds to the perceived threat
• Immune system memory is formed
• if the real pathogen arrives there is a rapid immune response

Question 20

Chemicals/fluids secreted as chemical barriers

Answer 20

• Sebaceous gland secretions
• Perspiration
• Tears
• Hydrochloric acid in the stomach
• Lysozymes
• Interferons

Question 21

Herd immunity

Answer 21

• If enough individuals are immune to a pathogen
• the pathogen cannot effectively spread through the population
• if not enough are immune, an epidemic can result

Question 22

Secondary immune response

Answer 22

• Short delay in response
• Rapid increase in production of antibodies
• Pathogen destroyed
• Little/no disease symptoms

Question 23

Visible signs of inflammation

Answer 23

• Swelling
• Redness
• area feels warm
• puss

Question 24

Pus

Answer 24

An accumulation of dead foreign matter, phagocytic cells and tissue cells

Question 25

Antibody mediated immune response

Answer 25

* B-lymphocytes specialise * Divide to produce plasma cells * Release antibodies * Pathogens destroyed by antibodies

Question 26

How are B and T-lymphocytes made

Answer 26

* Stem cells in bone marrow grow into B- and T-lymphocytes * B-lymphocytes accumulate in the lymph nodes * T-lymphocytes first mature in the thymus gland before accumulating in the lymph nodes

Question 27

Internal plant defence against microbes

Answer 27

* Receptors called resistance proteins * recognise specific pathogens or strains to activate a chemical response * Bioflavonoids - substances which are antibacterial and antiviral * Genetic resistance - genetically less prone to certain pathogens * Wound healing - ability to seal up injuries and produce chemicals to prevent pathogens from entering

Question 28

The lymphatic system

Answer 28

* Lymph vessels * Lymph nodes * Lymph fluid containing lymphocytes

Question 29

Examples of a plants passive defences against microbes

Answer 29

* Waxy cuticle * Thick bark * Bioflavonoids (anti microbe chemicals)