4.6 Disease, defense and treatment Flashcards
Define Pathogen.
A pathogen is a microorganism that causes disease.
These microorganisms include fungi, protists, bacteria, and viruses.
Name the six ways pathogens can be spread.
- Contact
- Aerosol
- Body fluids
- Water
- Insects
- Contaminated food
Name three main body defences against pathogens. (Not including the immune system)
- Skin sebum: Bacteria that make it difficult to resist infection by microorganisms.
- Intact skin is a barrier and blood clots immediately around wounds.
- Stomach acid and lysozome in tears protect where skin is not present.
What is the function of White Blood Cells in the body?
If microbes manage to enter the body then white blood cells in the body will respond.
Foreign Contaminent!
What are the two types of White Blood Cell?
- Phagocytes
- Lymphocytes
What are the three stages of a phagocyte in action?
Microbes have proteins on their surface called antigens.
- The phagocytes recognise the antigens on the microbe as an invader.
- The phagocyte engulfs the microorganism.
- Enzymes inside the phagocyte digest the microorganism.
How do antibodies in lymphocytes destroy microbes?
- Mark the microbe for destruction by the phagocytes.
- Clump microbes together so many can be destroyed at once.
- Cause the destruction of the microbe.
What are the stages of drug development?
- Preclinical drug trials
- Testing on human cells grown in the laboratory.
- Testing on animals.
- Testing on healthy human volunteers. - Clinical trials
- Testing on small groups of patients.
How do clinical trials avoid the placebo affect?
- Blind trial: Patients do not know if they have been given the drug or placebo but the doctors know, or;
- Double blind trial: Neither patients nor doctors know if the patient has been given the drug or the placebo. Only the researchers know.
How do vaccinations use lymphocytes in the body to create immunity?
- A lymphocyte recognises the antigen of an invading microorganism.
- Lymphocyte produces the specific antibody to neutralise the microorganism.
- The lymphocyte cell divides repeatedly, producing many clones of the cell, all producing the same specific antibody.
- Once the microorganisms have been destroyed all the clone cells die off except a few. These cells are memory cells.
- If the same microbe is encountered again the antibodies will be produced faster and in larger numbers, hopefully destroying the microbes before symptoms are felt.
- Immunity can be developed if you have a disease or if you are given a vaccination. This is a dead, attenuated part of the microbe with the antigen on.
What three diseases are you expected to know in the exam?
- AIDS
- Chlamydia
- Malaria
What causes AIDS?
HIV (Human Immunodeficiency Virus)
What is the effect of AIDS?
Infects lymphocytes leading to lack of immunity to other infections.
What is the treatment for AIDS?
Antiviral drugs taken for life.
How can AIDS be prevented from spreading?
AIDS is spread by blood to blod contact - Use disposable gloves and use condoms to prevent spread.
Or just don’t shag lol
What causes Chlamydia?
Chlamydia trachmatis (bacteria)
What is the effect of Chlamydia?
Causes infertility in adults, conjunctivitis and lung problems in babies.
What is the treatment for Chlamydia?
Antibiotics like tetracycline/erythomycin
How can Chlamydia be prevented from spreading?
Chlamydia is sexually transmitted - use condoms to prevent spread.
Or just stop with the ladies, Chad!
What causes Malaria?
Plasmodium (Protist)
What is the effect of Malaria?
Destroys red blood cells causing fever.
What is the treatment for Malaria?
Antimalarial drugs, paludrine or daraprim to kill the plasmodium.
How can Malaria be prevented from spreading?
Malaria is spread by female Anopheles mosquitos.
Prevention meausres include:
- Killing mosquitos with insecticide
- Releasing large numbers of infertile make mosquitos
- Biological control of mosquitos
- Use of mosquito nets and repellents.
Who discovered Penecillin?
Alexander Fleming
How was Penecillin made?
By a fungus.
What is the function of an Antibiotic?
Antibiotics like Penecillin destroy bacteria or stop their growth.
What are the limitations of Antibiotics?
- Antibiotics work only on bacteria and fungi. They do not kill viruses.
- Antibiotics are much less effective against antibiotic resistant bacteria such as MRSA.
What is MRSA?
MRSA is an antibiotic resistant bacteria that is causing problems in hospitals. This may have developed from over use of antibiotics.
How can MRSA spread be prevented?
MRSA spread can be prevented via good hygeine such as hand washing, alcohol gels, effective cleaning of hospital wards etc.
