Fighting disease
Cards (16)
- Skin acts as a barrier to prevent pathogens entering the body. It also secretes antimicrobial substances which kill pathogens.
- Hairs and mucus trap pathogens from entering nose and prevent them from entering the body.
- Trachea and bronchi secrete mucus to trap pathogens.
- Stomach produces hydrochloric acid which kills pathogens.
- White blood cells can attack pathogens in 3 ways
- Phagocytosis
- Producing antibodies
- Producing antitoxins
- Phagocytosis is the process of white blood cells engulfing and digesting foreign cells.
- Each pathogen has antigens on surface. B-lymphocytes (a type of WBC) produce antibodies to lock onto the invading cells so they can be found and destroyed by other white blood cells. Antibodies (which are specific to antigen) then produce rapidly.
- White blood cells can counteract toxins by producing antitoxins.
- Vaccinations involve injecting small amounts of dead or inactive pathogens which carry antigens. This allows the body's B-lymphocytes to produce antibodies to attack them.
- MMR vaccine contains weakened versions of measles, mumps and rubella
- Vaccines have helped control lots of communicable diseases that used to be common in the UK. Smallpox no longer occurs at all and polio infections have fallen by 99%
- Epidemics can be prevented if large percentage of population is vaccinated as there are fewer people that can pass it on. This is called herd immunity
- Bad reactions to vaccines are rare
- Bacteria can mutate and become resistant to antibiotics. Individual resistant bacteria will survive and reproduce and the population of the resistant strain will increase.
- Resistant strains can cause a serious infection that can't be treated by antibiotics for example MRSA is resistant to the antibiotic meticillin.
- To decrease the rate of development on resistant strains
- doctors avoid overprescribing antibiotics
- patients finish whole course of anitbiotics