Defense against disease Flashcards
What are infectious diseases caused by?
Micro-organisms (properly called pathogens, as not all icro-organisms cause disease)
How many different types of micro-organisms are they and what are they called?
3 - Bacteria, fungi and virus’
Name the 6 ways which diseases are spread?
- Droplet infection
- Direct contact
- Indirect contact
- Vectors (animals, insects)
- Waterborn
- In food
Explain how the way of spreading disease: direct contact works?
This is person to person.
This can occur when an individual with the pathogen touches, coughs or kissed someone who isn’t infected.
These pathogens can also spread through the exchnage of body fluids from sexual contact/blood transfusions
Animal→person
Mother→unborn child
Explain Indirect contact spreads disease
Many pathogens can linger on objects like doorhandles/
When you touch the same doorhandle you can pick up the pathogen, if you then touch your eyes, mouth or not efoe washing your hands, you may become infected.
Explain how droplet transmission spreads disease
When you cough/sneeze, you expel droplets into the air around you. When you’re sick with a cold/flu. The droplets contain the pathogen that caused your illness.
Explain how food contamination spreads disease
Pathodens can infect you through contaminated food and water. When you eat foods contaminated with e-coli, you get food poisoning.
How do bacteria make you feel ill?
By damaging your cells and producing toxins
How do viruses make you feel ill?
Viruses relpicate themselves by invading your cells and producing many copies of theselves, your cell withh usually then burst
Exam answer on how viruses work in the body
- Gain entrance to the human body
- Enter cells and reproduce rapidly
- Burst the cell
What things stop bad things from trying to getting in to your body?
Skin, hairs and mucus in your respiratory tract, platelets clotting blood
Explain how WBC’s deal with pathogens
- They engulf foreign bodies and digest them
- They produce antibodies
→ All invading cells have antigens on their surface. When your WBC comes across the foreign antigen they start to produce specific proteins called antibodies to lock onto and kill the invading cells
→ The antibodies are then produced rapidly and carried around the body to kill all similar bacetia or viruses
→If the person is infected with the same pathogen again the WBC will rapidly produce the correct antigens to kill it (the person is naturally immune)
- Antitoxins are produced, which counteract toxins produced by the invading bacteria
What is injected during a vaccination?
A dead, inactive, weakened or fragmented microorganism
Pro’s of vaccines?
- They’ve helped control lots of infectious diseases that were once common in the UK (eg polio, measles, whooping cough, rubella, mumps, tetnus)
→ Smallpox was illiminated and polio infections have fallen by 99%
- Epidemics can be prevented is a large percentage of the population is vaccinated
→This means even people who aren’t vaccinated are unlikely to catch ut because they are fewer people able to pass it on
Cons of vaccines?
- They don’t always work, aka they don’t always give you immunity
- You can sometimes have a bad reaction to a vaccine (eg swelling, fever, seizures?) but they’re very rare
