Infection and Response Flashcards
(29 cards)
Describe bacteria
- once inside the human body, reproduces very rapidly
- can release harmful chemicals called toxins
- toxins damage tissues and make us feel ill
Describe viruses
- cannot reproduce by themselves
- can only reproduce inside a host cell
- very damaging to the cell
- when the virus leaves the cell, it can cause the cell to burst open and die
How are pathogens spread
- air e.g. water droplets sneezing and coughing
- directly through water like cholera
- direct contact between individuals
How to prevent spread?
- clean drinking water
- washing hands
- condom during intercouse
- vaccination
- isolation
Symptoms, spread, effects and prevention of measles
symptoms
- fever
- a red skin rash 3 days after
spread by:
-droplets when an infected person sneezes or coughs
effects:
-can cause damage to the brain and breathing system
prevention:
-children should be vaccinated very young
Symptoms, treatment, transmission and prevention of HIV
symptoms:
- flu like illness which usually disappears after 1-2 weeks
- virus attacks the rest fo the immune system, damaging it over time severely
- patient becomes unable to fight off other infections and cancer cells
- this is called AIDS
Treatment:
- antiretroviral drugs stop the virus from multiplying in the patient so it doesn’t damage the immune system
- they will not develop AIDS and are able to live a normal life
Transmission:
- exchange of bodily fluids between humans
- sharing infected needles
Symptoms, transmission and prevention of salmonella.
symptoms:
- fever
- abdominal cramps
- vomitting
- diarrhoea
transmission:
- eating infected food that is prepared in unhygenic conditions
- bacteria secrete toxins that cause the symptoms
prevention:
- cook meat thoroughly
- vaccinate chickens
Gonorrhoea symptoms, prevention and treatment
symptoms:
thick green/yellow discharge from the penis or vagina
pain when urinating
treatment:
- antibiotics (penicillin)
- however antibiotic resistant strains are now common
prevention:
- use condoms
- get tested if you have unprotected sex
What is a protist?
- single celled eukaryotes
- often transferred to an organism by a vector
Symptoms and preventing malaria
How is malaria spread?
symptoms:
-repeated bolts of fever
prevention:
- stop them breeding by draining areas with still water
- spray areas of still water with insecticide
- sleep under a mosquito net sprayed with insecticide
how is it spread?
- infected person is bitten by a mosquito
- the malaria pathogen passes into the mosquito
- now it bites into another person and passes it into them
How does the skin prevent pathogens from entering the body?
- forms protective layer covering the body
- outer layer consists of dead cells and is difficult for pathogens to penetrate
- prodeces sebum which kills bacteria
- when it is damaged, it scabs over to prevent pathogens from entering
How does the nose prevent pathogens from entering the body?
-contains hair and mucus which traps pathogens before they enter the breathing system
How do the lungs prevent pathogens from entering the body?
- trachea and the bronchi are covered with tiny hairs called cilia
- cilia is covered in mucus which traps pathogens
- now wafts the mucus upwards towards the throat where it is swallowed into the stomach
How does the stomach prevent pathogens from attacking the body?
- contains hydrochloric acid
- kills pathogens before the go further into the digestive system
What does the immune system do?
Destroys pathogens and any pathogens they produce.
Explain phagocytosis
- WBC detects chemicals released from the pathogen and moves towards it
- WBC then ingests the pathogens
- the WBC uses enzymes to destroy the pathogens
What are antibodies and how do they work?
- protein molecules produced by the WBCs
- the antibodies stick to the pathogens
- triggers the pathogens to be destroyed
- extremely specific
- will not protect you against any other pathogen
- remain in the blood for a very long time
How do antitoxins work?
- WBCs produce these
- they stick to toxin molecules and prevent them from damaging cells
How does a vaccination work?
- introduce small quantities of a dead/weakened pathogen into the body
- won’t lead to disease
- WBCs are now stimulated to produce antibodies against it
- WBC divides by mitosis to produce lots of copies of itself
- they can stay in the blood for decades
- if the same pathogen enters, the WBCs can produce antibodies quickly, preventing infection
What is herd immunity?
- important that many people get vaccinated
- if enough people are, it protects unvaccinated people
- there won’t be anyone around the unvaccinated person that can pass the pathogen on
Why is it difficult to develop drugs that kill viruses?
- viruses live and reproduce inside human cells
- so the drugs could damage the body’s cells and tissues
What do lymphocytes produce antibodies against?
Antigens
explain the monoclonal anitbody mouse thing
- inject a mouse with antigen
- lymphocytes will produce antibodies against it
- collect the lymphocytes from the mouse
- fuse the lymphoyctes with the tumour cell
- tumour cells are very good at dividing by mitosis
- hybridoma cell produced
- these can produce antibodies and divide by mitosis
- select a single hybridoma producing the antibody we want
- hybridoma divides by mitosis to form a clone of identical cells
- antibodies produced are all identical
How are monoclonal antibodies used in pregnancy testing?
- detect a specific hormone
- which is produced by the placenta of the developing fetus
- cheap and easy to use
- simply urinate and look for a reaction
- highly accurate
