Topic 10 Flashcards
(21 cards)
What is a pathogen?
A microorganism that causes disease
What is a transmissible disease?
A disease which can be passed between hosts
Give 5 ways diseases can be spread
Droplet infection
Eating contaminated food
Drinking contaminated water
Direct contact
Entry through wounds
Give an example of how a pathogen can be transmitted by direct contact
skin contact, saliva, semen
Give an example of how a pathogen can be transmitted by indirect contact
contaminated surfaces or food, mosquitos, droplets in inhaled air
State 2 chemical defences the body uses to prevent infection
Strong stomach acid kills pathogens
Mucus contains antimicrobial chemicals
State 2 mechanical defences the body uses to prevent infection
Nasal hairs used to trap and waft dirt and microbes to prevent entry into the airway
The skin acts as a barrier to pathogens
Give 2 ways that white blood cells protect the body from infection
Phagocytosis (engulfing pathogens)
Producing antibodies which attach onto pathogens
How do antibodies work?
Specific antibodies bind to antigens on the pathogen
The antibodies can either destroy the pathogen or make the pathogen easier for white blood cells to engulf
Why can only certain antibodies bind to certain pathogens?
Antibodies have specific shapes and can only bind to specific and complementary antigens on pathogens
What is active immunity?
Active immunity is a type of immunity where white blood cells produce specific antibodies against a pathogen
State 2 ways that active immunity can be obtained
Vaccination, Infection with the pathogen
How do vaccines work?
Dead, inactive or weakened pathogens are injected into the body
The body produces antibodies against the pathogen
Memory cells are also created to provide long term immunity
Give 4 methods of controlling the spread of disease
Hygienic food preparation (storing food in appropriate conditions, washing equipment)
Good personal hygiene (using tissues, washing hands and cleaning regularly)
Waste disposal
Sewage removal and taking precautions to ensure it does not contaminate drinking water
What are the symptoms of cholera?
diorrhoea, dehydration and loss of ions from the blood
How is cholera transmitted?
In unclean water
Explain what causes cholera symptoms
Toxin causes chloride ions to be released into the inntestines lowering the water potential here. This causes water to follow by osmosis causing watery faeces.
What is herd immunity?
Where the vast majority of a population are vaccinated which prevents the disease from spreading as there are fewer unvaccinated individuals for the disease to spread between
What is passive immunity?
Where an individual is provided with short term immunity by receiving antibodies from another individual (typically a mother to an infant)
Why is passive immunity only short term?
No memory cells are produced
Why is passive immunity important to breastfed infants?
The infants have not yet had time to develop their own antibodies as they have not been exposed to as many pathogens
