Chaoter 10 Disease And Immuntuy

Question 1

Describe pathogen

Answer 1

Disease causing organism

Question 2

Describe transmissible disease

Answer 2

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

Question 3

How are pathogens transmitted

Answer 3

Durcect contact - through transfer of blood or body fluids
Indirect - through contaminated surfaces, food ,animals and air

Question 4

Describe body defences

Answer 4

Mechanical
Skin - prevents infection from pathogen
Hair in the nose- filter out particles that could contain pathogen
Chemical barriers
Stomach acid- contains HCL which kills bacteria
Mucus- traps pathogens which are then moved away
White blood cells
Phagocytosis- engulfing pathogens which
Lymphocytes- pay producing antibodies

Question 5

Controlling the spread of disease

Answer 5

A clean water supply
water can contain many different pathogens and can cause water bone diseases like Cholera

Hygienic food preparation
do not keep food at room temperature for long
wash hands before touching
keep animals away from food

Personal hygiene

Waste disposal

Sewage treatment
Remove harmful pathogens from waste before it’s released

Question 6

Describe cholera

Answer 6

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

Question 7

Describe antigens and antibodies

Answer 7

Antibodies are proteins that bind to antigens leading to direct destruction of pathogens or marking of pathogens for destruction by phagocytosis
Specific antibodies have complimentary shapes which fit specific antigens
Each pathogen has its own antigen which have specific shapes
Antibodies, clump pathogen together and release chemicals that signal destruction of the pathogen)

Question 8

Describe what happens when a pathogen enters the body and why it takes time to recover

Answer 8

If pathogen enters his body
Lymphocytes with antibodies that have a complimentary shape to the antigens on the pathogens will recognise the pathogen
It will quickly divide itself by mitosis
Then it will secret antibodies to destroy the pathogen

This immune response takes time as first it has to recognise the pathogen then divide which might take a day in the meantime pathogens breed making you ill

Question 9

Describe memory cell

Answer 9

When lymphocytes makes clone not all are used to make antibodies, some remain in the blood as memory cells
Same kind of pathogen enters the body. These memory cells will already be ready and waiting for them.
Memory cells will quickly produce antibodies and destroy the pathogen before it breeds
Patient has become immune to that pathogen
Memory cells are not produced in passive immunity ~

Question 10

Describe vaccination

Answer 10

Weekend pathogen or their antigens are inserted into the body

Antigen stimulate an immune response by lymphocytes e which produce antibodies
Memory says they’re also produced which give long-term immunity

Question 11

Controlling disease by vaccination

Answer 11

If large enough percentage is vaccinated, it provides protection for the entire population. This is because there are very few places for the pathogen to breed.

Question 12

Describe active and passive immunity

Answer 12

Active immunity is long-term defence from pathogens by antibody protection in the body
-Having a disease and recovering from it
-Vaccination (injected with pathogens)
Active immunity is slow acting and provides long lasting immunity

Passive immunity is a short term defence against pathogens by antibody acquired from another individual
-Breastfeeding
-Injected with antibodies
Memory cells are not made
Passive immunity as fast acting and short-term defence