Keeping Healthy: Understanding Diseases and Prevention
Keeping Healthy
Lifestyle Diseases
Types of Microorganisms That Can Cause Disease:
Virus:
- Flu (Gripe)
- Polio
- Common Cold (Resfriado Común)
- AIDS (SIDA)
- Measles (Sarampión)
- Meningitis
- Rabies
- Chicken Pox (Varicela)
- Papilloma
Microorganisms that can only live and reproduce inside living cells.
Bacterium:
- Tonsillitis (Anginas)
- Tuberculosis
- Plague (Plaga)
- Cystitis
- Tetanus
- Botulism (Enfermedad producida cuando te comes alimentos en malas condiciones)
- Cholera (Cólera, Gastroenteritis)
One type of single-celled microorganism. They do not have a nucleus. Some bacteria may cause disease.
Fungus:
- Athlete’s Foot
- Thrush (Candidiasis) (Candida albicans is a common fungus that causes thrush, it lives in warm, moist body surfaces)
- Ringworm (Tinea)
Group of living things including some microorganisms that cannot make their own food.
Protozoa:
- Malaria (Vector: Plasmodium)
- Sleeping Sickness (Trepanosoma) (Vector: Tse-tse Fly)
The parts of the body that fight infections are called the immune system (white blood cells are an important part).
Antibiotics are chemicals that kill bacteria and fungi.
Side Effects of Antibiotics:
For example, with the infection of thrush. When your skin is covered with bacteria, and most bacteria are harmless to you, the bacteria can prevent the invasion of other microorganisms. If you take antibiotics, they kill both (good and bad bacteria), but they don’t kill the fungus. With the protective bacteria gone, the fungus grows quickly, and the patient gets symptoms of thrush.
Vaccines
Vaccinations make use of the body’s own defense system; they make our white blood cells work and create antibodies so we become immune to a disease without having to catch it first.
Process:
Small amounts of disease microorganisms are put into your body. Dead or inactive forms are used so you don’t get the disease itself.
White blood cells recognize the foreign microorganisms and make the right antibodies.
Antibodies make the microorganisms clump together, and they are digested.
If you get the real disease microorganism, your body will produce the antibodies you need very quickly.
Flu Vaccine:
- – Small risk of reaction to the vaccine
- – Costs of providing the vaccine
- + Much smaller risk of suffering from the flu
- + If people don’t get the flu, the NHS saves money
Why are new flu vaccines made each year?
The virus reproduces very quickly and has a very high mutation rate.
New kinds of flu virus develop regularly, so a different vaccine is needed against each new flu virus.
Fighting AIDS:
It is caused by the HIV virus; it kills millions of people worldwide every year.
The problem is that the AIDS virus damages the immune system itself, and this makes it poor at fighting off other infections. (A person with AIDS can become very ill from an infection that a healthy person would quickly fight off.)
The other problem is that we don’t have a vaccine against HIV. It mutates very quickly, so a vaccine would probably be useless before it had been fully tested.
Smallpox (Viruela)
In the 1950s, there were 50 million cases of this devastating disease. In 1967, it came down to 10-15 million because of vaccination (the World Health Organization began a campaign to wipe out smallpox by vaccines). In 1977, the last case of smallpox was recorded in Somalia, Africa.
Now, it has a much lower mutation rate than the flu virus, for example, because the vaccine was really effective across the world.
Antibiotics
Mold is a fungus that makes penicillin. In the 1940s, scientists started to grow the fungus to make larger amounts of penicillin.
Antibiotics have developed with penicillin, but some resistant bacteria appeared soon. It’s the genes of a “superbug” that make it resistant. A tiny change in one gene, a mutation, can turn a bacterial cell into a superbug.
Using Radiation
Microwave Ovens:
- Different absorption of materials.
- Nutrients absorb microwaves (fats, water, sugar…).
- Vibration of particles makes them heat.
- Mugs or bowls must not be hot; they are transparent to microwave radiation.
- The metal walls reflect it.
- Microwave radiation is absorbed deeply, so a potato could be hot inside and cool near the skin (grill heater emits infrared radiation).
- The power setting (intensity) and the cooking time (exposure time).
Mobile Phones:
Phone masts send microwave radiation, and mobile phones send the radiation back.
The power of emission is very low from the mobile phone.
The brain and skull can absorb part of the radiation (hands-free kits).
What about the radiation emitted by the phone masts?
If you stand directly under a mast, the radiation you receive is scarce.
X-ray Safety
Discovered in the 19th century by Wilhelm Roentgen.
Ionizing radiation.
They go through skin, muscles, or fat.
Effects on cells in active division (embryos and small children).
Correlation between x-rays and cancer. (Alice Stewart)
ALARA principle: as low as reasonably achievable.
- Time: Time of exposure/radiation absorbed (digital detectors).
- Distance to the source.
- Shielding (lead screens).
To detect lung or breast cancer (mammography), kidney stones, cysts, or tumors.
CT or scanner combines X-rays + computer (computerized tomography).