Chapter 10 - Disease and Immunity Flashcards
Define pathogen
a microorganism that causes disease
Name 3 examples of disease that viruses cause
- influenza
- common cold
- poliomyelitis
- measles
- AIDS / HIV
- covid - 19
Name 3 examples of disease that bacteria cause
- cholera
- syphilis
- whooping cough
- tuberculosis
- tetanus
Name 1 example of a disease that protoctists cause
- malaria
- amoebic dysentery
Name 1 example of a disease that fungi cause
- athlete’s foot
- ringworm
Define host
the organism that the pathogen lives in and reproduces within
Define infection
the entry of a pathogen into the body
Where can infections enter?
- air
- cuts
- water
Define tranmission
the movement of a pathogen from on host to another
Define transmissible disease
diseases caused by pathogens that can be passed from one host to another
In what 2 ways do pathogens damage our cells when inside the body?
- using up resources
- producing toxins which cause symptoms
What are the 2 characteristics of toxins caused by pathogens?
- waste products
- some can be highly poisonous
What are the 2 ways in which diseases can be transferred?
direct and indirect contact
Name an example of direct transfer of a disease
pass through blood
Name 3 examples of indirect transfer of a disease
- breathing in droplets (coughing, sneezing)
- touching a surface an infected person touched (e.g. food poisoning)
- eating or drinking from the same source if an infected person
- contact with animals carrying pathogens
What happens in the skin is broken?
a blood clot forms to seal wound and prevent pathogens from getting in
How does the stomach kill bacteria in food?
using HCl
How does the nose prevent pathogens from entering the body?
nose hairs which filter air
What happens when we smell or taste something bad?
our body doesn’t want it
What does the mucus in airways do to prevent pathogens from entering?
traps bacteria and swallows it instead of going to lungs
In what ways can we ensure safe and clean water?
filter water and treated with chlorine
Can water contain pathogens?
yes
We use what we know about bacteria to ensure they stay away from food and drinks. What do we do to ensure this? (4)
- keep microbes away
- keep animals away
- keep food at low or high temperatures
- keep raw meat away
What can happen if oil on skin builds up?
it can collect dirt and microbes
What substances that can accumulate on the skin can be breeding ground for bacteria?
- sweat
- dirt
- oil
How can we prevent teeth decay and keep microbes away from mouth?
brush teeth
Do animals search for food in waste?
yes
Why should waste be collected regularly?
- avoid infection
- avoid pollution
What can trash be rotted by?
decomposers
What gas do bacteria produce?
methane gas that is highly flammable
Sewage =
waste liquid
Name 3 examples of where sewage comes from
- bathrooms
- kitchens
- factories
Name 3 examples of substances that can be in sewage
- urine
- oils
- toilet paper
- detergents
How is cholera spread?
through water / food that has been contaminated by the faeces of an infected person
Name a place where cholera can spread quickly
refugee camps
Explain how cholera infects the body
- cholera bacteria are ingested and multiplied
- bacteria attach to alimentary canal walls
- bacteria release toxins
- toxins cause Cl⁻ ions to be released
- this causes water to move into lumen by osmosis
- now there is a lot of water in the canal. blood contains too little Cl⁻ ions and water
How can cholera be fatal?
dehydration
How can a person recover from cholera?
if enough fluid is replaced
Define antibodies
molecules secreted by white blood cells (lymphocytes only) which bind to pathogens and destroy them
What are antibodies?
proteins that have a specific shape which is complementary to an antigen
Define antigen
a chemical that is recognised by the body as being ‘foreign’ and stimulates the production of antibodies
Where are antigens usually located on a pathogen?
on the outside
How are antibodies shaped?
specifically to fit the shape of the specific antigen
How do antibodies eliminate pathogens?
by attaching to the antigens, forming clumps and ‘feeing’ those clumps to a lymphocyte.
Define immune response
the reaction of the body to the presence of an antigen
Define memory cells
long-lived cells produced by the division of lymphocytes that have contacted an antigen. they respond quickly to future contact with the same antigen
This is how antibodies react when exposed to contaminated food. What does the graph look like after eating the same contaminated food again?
For how long do memory cells stay in the blood after an immune response?
a long time
Define vaccination
a harmless preparation of dead or inactivated pathogens that is injected into the body to start the immune response
What 3 substances can vaccines be made of?
- dead cells from disease
- pieces of cells from disease
- cells made from a similar disease
★ What are vaccines never made of and why?
never from inside of cells because antigens is what stimulates immune system
Why do some diseases require 2 vaccinations?
for long lasting immunes
What are the 2 vaccines called and what is their purpose?
First dose: partial protection - stimulates production of some memory cells
Second dose: “booster” - stimulates production of even more memory cells
How can someone have active immunity?
if their body made its own antibodies and memory cells
How is active immunity developed?
- having disease and recovering
- being vaccinated
Can active immunity last a lifetime?
yes
How can someone have passive immunity?
if they have been given ready-made antibodies
How can passive immunity be developed?
- injection
- babies get this through breast feeding
What does a human have to do if they get bitten by an animal with rabies?
have to get an injection or else it could be fatal within 48 hours
When can the milk passed from mother to child help?
during the first few months of life
Why does passive immunity last for a short amount of time?
because it is broken down (no memory cells are created)
What can polio do to children?
leave them partially paralyzed
How can polio be spread?
through water
Why is herd vaccinating useful?
- vaccinating children does not only protect the chldren vaccinated but also those around them
- there are fewer places for the pathogen to replicate
