Unit 10 - diseases and immunity

Question 1

pathogen defenition

Answer 1

disease causing organism

Question 2

transmissible disease definition

Answer 2

a disease in which the pathogen can be passed from one host to another

Question 3

Two type of ways a disease can be transmitted, and examples

Answer 3

• direct contact eg blood or other bodily fluids
• indirect contact eg contaminated surfaces or food, from animals, airborne pathogens

Question 4

3 types of defense systems and examples

Answer 4

1. mechanical barriers; skin, nose hairs
2. chemical barriers : mucus, stomach acid, antibacterial tears
3. cellular barriers: phagocytosis and antibody production by lymphocytes. this can be enhanced by vaccination.

Question 5

function of lymphocytes

Answer 5

tag foreign material (known as antigen) with antibodies, targeting the material for destruction

Question 6

function of phagocytes

Answer 6

eat/engulf foreign material through phagocytosis

Question 7

what are antigens

Answer 7

any structure that can be identified by an immune system (usually proteins)

Question 8

how is the shape of antigen important

Answer 8

is complimentary to the binding groove of the antibody

Question 9

what happens once the antibody-antigen complex is formed

Answer 9

foreign material is marked for destruction by phagocytes

Question 10

5 ways to control the spread of diseases

Answer 10

1. clean water supplies
2. hygienic food prep
3. good personal hygiene
4. waste disposal
5. sewage treatment

Question 11

process of vaccination

Answer 11

1. a weakened pathogen or specific antigen is put into the body
2. the antigen stimulates lymphocytes to produce antibodies
3. complimentary antibody bind to the antigen, tagging it for destruction by phagocytes
4. memory cells are produced that allow for antibody to be produced rapidly in the future, giving you immunity

Question 12

why do we feel sicker from first infections

Answer 12

• it takes our body many days to create antibodies that will fit an antigen if we have never been exposed to it
• the 2nd time our body is exposed it recognises the antigen much faster and can start producing antibodies within hours

Question 13

what is active immunity

Answer 13

defense against a pathogen by producing the antibody within the body

Question 14

how is active immunity gained

Answer 14

after an infection or by vaccination

Question 15

what is produced in active immunity

Answer 15

memory cells

Question 16

what is passive immunity

Answer 16

short term defense against a pathogen by antibodies acquired from another individual eg mothers milk, across the placenta

Question 17

are memory cells produced during passive immunity

Answer 17

no

Question 18

what is cholera

Answer 18

a disease caused by a bacterium which is transmitted in contaminated water.

Question 19

How does cholera cause illness

Answer 19

the cholera bacterium produces a toxin that causes secretion of chloride ions into the small intestine, causing osmotic movement of water into the gut, causing diarrhoea, dehydration , and loss of ions from the blood.